WorldWideScience

Sample records for 120-to-200 ghz frequency

  1. Three MMIC Amplifiers for the 120-to-200 GHz Frequency Band

    Samoska, Lorene; Schmitz, Adele

    2009-01-01

    Closely following the development reported in the immediately preceding article, three new monolithic microwave integrated circuit (MMIC) amplifiers that would operate in the 120-to-200-GHz frequency band have been designed and are under construction at this writing. The active devices in these amplifiers are InP high-electron-mobility transistors (HEMTs). These amplifiers (see figure) are denoted the LSLNA150, the LSA200, and the LSA185, respectively. Like the amplifiers reported in the immediately preceding article, the LSLNA150 (1) is intended to be a prototype of low-noise amplifiers (LNAs) to be incorporated into spaceborne instruments for sensing cosmic microwave background radiation and (2) has potential for terrestrial use in electronic test equipment, passive millimeter-wave imaging systems, radar receivers, communication receivers, and systems for detecting hidden weapons. The HEMTs in this amplifier were fabricated according to 0.08- m design rules of a commercial product line of InP HEMT MMICs at HRL Laboratories, LLC, with a gate geometry of 2 fingers, each 15 m wide. On the basis of computational simulations, this amplifier is designed to afford at least 15 dB of gain, with a noise figure of no more than about 6 dB, at frequencies from 120 to 160 GHz. The measured results of the amplifier are shown next to the chip photo, with a gain of 16 dB at 150 GHz. Noise figure work is ongoing. The LSA200 and the LSA185 are intended to be prototypes of transmitting power amplifiers for use at frequencies between about 180 and about 200 GHz. These amplifiers have also been fabricated according to rules of the aforesaid commercial product line of InP HEMT MMICs, except that the HEMTs in these amplifiers are characterized by a gate geometry of 4 fingers, each 37 m wide. The measured peak performance of the LSA200 is characterized by a gain of about 1.4 dB at a frequency of 190 GHz; the measured peak performance of the LSA185 is characterized by a gain of about 2

  2. Experimental Study of a Frequency Doubling, 70 GHz Gyroklystron

    Walter, Mark; Nusinovich, Gregory; Lawson, Wes; Granatstein, Victor; Miller, Thomas; Levush, Baruch; Danly, Bruce

    2000-10-01

    Interest is on the rise for frequency doubling designs for production of high power mm-waves in advanced radar applications. Initial experimental results will be presented for our frequency doubling, second harmonic, 70 GHz gyroklystron. The circuit has been designed based on the electron gun, input coupler, and input cavity used in previous experiments at the Naval Research Laboratory (NRL) performed at 35 GHz. The input cavity is driven by a 35 GHz driver and operates in the TE011 mode at the fundamental cyclotron resonance, while the buncher, penultimate, and output cavity operate in the TE021 mode at twice the signal frequency at the second cyclotron harmonic. The suite of codes developed at NRL - MAGYKL, CASCADE, and QPB were used to design the circuit. These codes predict an output power of 130 kW, with an efficiency of 23

  3. Long term variability of radio sources in the frequencies of 22 GHz and 44 GHz

    Botti, L.C.L.; Abraham, Z.

    1987-05-01

    The radio sources 3C273, OV236, Cen A and Sgr A were observed during a period of six years (1980-1986), in the frequencies of 22 GHz and 44 GHz, with the Itapetinga radiotelescope (Brazil). The objective of this work was the detection of variability in the intensity and in the shape of the spectra of the sources. All of them presented some variability, specially the quasar 3C273, which after a period of intense activity (1981-1985), returned to its quiescent level at the end of 1985. The increase of the flux density in these frequencies is associated to the ejection of new components by the central source in the quasar, as observed in the maps obtained by VLBI techniques. 17 references, 4 figures.

  4. Design of tunable GHz-frequency optomechanical crystal resonators

    Pfeifer, Hannes; Zang, Leyun; Painter, Oskar

    2016-01-01

    We present a silicon optomechanical nanobeam design with a dynamically tunable acoustic mode at 10.2 GHz. The resonance frequency can be shifted by 90 kHz/V^2 with an on-chip capacitor that was optimized to exert forces up to 1 $\\mu$N at 10 V operation voltage. Optical resonance frequencies around 190 THz with Q factors up to $2.2 \\times 10^6$ place the structure in the well-resolved sideband regime with vacuum optomechanical coupling rates up to $g_0/2\\pi = 353$ kHz. Tuning can be used, for instance, to overcome variation in the device-to-device acoustic resonance frequency due to fabrication errors, paving the way for optomechanical circuits consisting of arrays of optomechanical cavities.

  5. Design and modeling of inductors, capacitors and coplanar waveguides at tens of GHz frequencies

    Aryan, Naser Pour

    2015-01-01

    This book describes the basic principles of designing and modelling inductors, MIM capacitors and coplanar waveguides at frequencies of several tens of GHz. The author explains the design and modelling of key, passive elements, such as capacitors, inductors and transmission lines that enable high frequency MEMS operating at frequencies in the orders of tens of GHz.

  6. Molecular Bremsstrahlung Radiation at GHz Frequencies in Air

    Samarai, I Al; Deligny, O; Letessier-Selvon, A; Montanet, F; Settimo, M; Stassi, P

    2016-01-01

    A detection technique for ultra-high energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular Bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons/neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be $2\\times10^{-21} $W cm$^{-2}$ GHz$^{-1}$ at 10 km from the shower core for a vertical shower induced by a proton of $10^{17.5}$ eV. In addition, a recent measurement of Bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.

  7. Molecular bremsstrahlung radiation at GHz frequencies in air

    Al Samarai, Imen; Bérat, Corinne; Deligny, Olivier; Letessier-Selvon, Antoine; Montanet, François; Settimo, Mariangela; Stassi, Patrick

    2016-03-01

    A detection technique for ultra-high-energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons and neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be 2 ×1 0-21 W cm-2 GHz-1 at 10 km from the shower core for a vertical shower induced by a proton of 1 017.5 eV . In addition, a recent measurement of bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.

  8. Intrinsic current gain cutoff frequency of 30 GHz with carbon nanotube transistors

    Le Louarn, A.; Kapche, F.; Bethoux, J.-M.; Happy, H.; Dambrine, G.; Derycke, V.; Chenevier, P.; Izard, N.; Goffman, M. F.; Bourgoin, J.-P.

    2007-06-01

    High frequency capabilities of carbon nanotube field-effect transistors (CNTFETs) are investigated. Structures with a large number of single-walled carbon nanotubes were fabricated using dielecrophoresis to increase the density of nanotubes in the device channel. The authors obtained an intrinsic current gain cutoff frequency of 30GHz establishing state-of-the-art high frequency (hf) potentialities of CNTFETs. The device also showed a maximum stable gain above 10dB at 20GHz. Finally, the parameters of an equivalent circuit model of multitube CNTFET at 20GHz are determined, which open the route to the modeling of nanotubes-based hf electronics.

  9. Dual frequency 230/690 GHz interferometry at the Submillimeter Array

    Hunter, T R; Blundell, R; Christensen, R D; Kimberk, R S; Leiker, S P; Marrone, D P; Paine, S N; Papa, D C; Patel, N; Riddle, P; Smith, M J; Sridharan, T K; Tong, C Y E; Young, K H; Zhao, J H; Hunter, Todd R.; Barrett, John W.; Blundell, Raymond; Christensen, Robert D.; Kimberk, Robert S.; Leiker, Steven P.; Marrone, Daniel P.; Paine, Scott N.; Patel, Nimesh; Riddle, Patricia; Smith, Michael J.; Young, Ken H.; Zhao, Jun-Hui

    2005-01-01

    The Submillimeter Array (SMA), a collaboration between the Smithsonian Astrophysical Observatory and the Academica Sinica Institute for Astronomy and Astrophysics of Taiwan, is an eight-element radio-interferometer designed to operate throughout the major atmospheric windows from about 180 to 900 GHz. In an effort to mitigate the effects of atmospheric instabilities which limit the phase coherence of the array especially in the higher frequency bands, the array was designed to allow simultaneous operation of a low frequency receiver (330 GHz). The overlap region of 330-350 GHz was included to facilitate dual polarization measurements in the frequency range considered to offer the highest sensitivity for continuum observations with the array. So far, the array is equipped with working SIS receivers covering the frequency ranges 176-256 GHz, 260-350 GHz, and 600-700 GHz, and single frequency operation has been routine in the lower two frequency bands for the past year. More recently, with the completion of IF h...

  10. A 20 GHz Bright Sample for Delta > 72 deg - II. Multi-frequency Follow-up

    Ricci, R; Verma, R; Prandoni, I; Carretti, E; Mack, K -H; Massardi, M; Procopio, P; Zanichelli, A; Gregorini, L; Mantovani, F; Gawronski, M P; Peel, M W

    2013-01-01

    We present follow-up observations at 5, 8 and 30 GHz of the K-band Northern Wide Survey (KNoWS) 20 GHz Bright Sample, performed with the 32-m Medicina Radio Telescope and the 32-m Torun Radio Telescope. The KNoWS sources were selected in the Northern Polar Cap (Delta > 72 deg) and have a flux density limit S(20GHz) = 115 mJy. We include NVSS 1.4 GHz measurements to derive the source radio spectra between 1.4 and 30 GHz. Based on optical identifications, 68 per cent of the sources are QSOs, and 27 per cent are radio galaxies. A redshift measurement is available for 58 per cent of the sources. The radio spectral properties of the different source populations are found to be in agreement with those of other high-frequency selected samples.

  11. 60 GHz Antenna Diagnostics from Planar Near Field Antenna Measurement Without External Frequency Conversion

    Popa, Paula Irina; Pivnenko, Sergey; Breinbjerg, Olav

    2015-01-01

    antenna diagnostics and perform a detailed systematic study of the extreme near-field of a standard gain horn at 60GHz from planar and spherical near-field measurement data. The magnitude and phase of all three rectangular components of the electric and the magnetic aperture fields are calculated, as is......We previously demonstrated that 60 GHz planarnear-field antenna measurements without external frequency conversion can provide far-field radiation patterns in good agreement with spherical near-field antenna measurements in spite of thecable flexing and thermal drift effects [P.I.Popa, S. Pivnenko......,J.M. Nielsen, O. Breinbjerg, 60 GHz Antenna Measurement Setup using a VNA without External Frequency Conversion,36th Annual Symposium of the Antenna Measurement Technique Association ,October 12-17,Tucson, Arizona, 2014]. In this work we extend the validation of this 60 GHz planar near-field (PNF) set-up to...

  12. Frequency notched wide slot antenna for UWB/2.4 GHz WLAN applications

    L(U) Wen-jun; ZHU Hong-bo

    2007-01-01

    A compact frequency notched microstrip slot antenna for ultra-wideband (UWB) /2.4 GHz-band wireless local area network (WLAN) applications is proposed. The antenna is similar to a conventional microstrip slot antenna; however, by introducing a cross wide slot and a meandered-slotted stub, both compact size and frequency notched function can be achieved. It has been studied both numerically and experi- mentally for its impedance bandwidth, surface current distribution, radiation patterns, and gain. As will be seen, an operation bandwidth of over 4.6:1 ranging from 2.39 to 11.25 GHz for return loss lower than having a frequency notched band ranging from 4.75 to 5.85 GHz has been achieved, and good radiation performance over the entire frequency range has also been achieved.

  13. Array of planar waveguide lasers with 50 GHz frequency spacing

    Guldberg-Kjær, Søren Andreas; Laurent-Lund, Christian; Sckerl, Mads W.

    1999-01-01

    Waveguide laser arrays are demonstrated using planar silica-on-silicon technology. Excellent control over frequency separation is obtained with a single phase mask.......Waveguide laser arrays are demonstrated using planar silica-on-silicon technology. Excellent control over frequency separation is obtained with a single phase mask....

  14. The widest-frequency radio relic spectra: observations from 150 MHz to 30 GHz

    Stroe, Andra; Rumsey, Clare; van Weeren, Reinout; Kierdorf, Maja; Donnert, Julius; Jones, Thomas W; Röttgering, Huub J A; Hoeft, Matthias; Rodriguez-Gonzalvez, Carmen; Harwood, Jeremy J; Saunders, Richard D E

    2015-01-01

    Radio relics are patches of diffuse synchrotron radio emission that trace shock waves. Relics are thought to form when intra-cluster medium electrons are accelerated by cluster merger induced shock waves through the diffusive shock acceleration mechanism. In this paper, we present observations spanning 150 MHz to 30 GHz of the `Sausage' and `Toothbrush' relics from the Giant Metrewave and Westerbork telescopes, the Karl G. Jansky Very Large Array, the Effelsberg telescope, the Arcminute Microkelvin Imager and Combined Array for Research in Millimeter-wave Astronomy. We detect both relics at 30 GHz, where the previous highest frequency detection was at 16 GHz. The integrated radio spectra of both sources clearly steepen above 2 GHz, at the >6$\\sigma$ significance level, supports the spectral steepening previously found in the `Sausage' and the Abell 2256 relic. Our results challenge the widely adopted simple formation mechanism of radio relics and suggest more complicated models have to be developed that, for ...

  15. Development of frequency step tunable 1 MW gyrotron at 131 to 146.5 GHz

    Samartsev, A.; Gantenbein, G.; Dammertz, G.; Illy, S.; Kern, S.; Leonhardt, W.; Schlaich, A.; Schmid, M.; Thumm, M., E-mail: andrey.samartsev@kit.edu [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2011-07-01

    Effective control of power absorption in tokamaks and stellarators could be achieved by the frequency tuning of ECH and CD power delivered by high-power gyrotrons. In this report some results of the development of a frequency tunable gyrotron with fused-silica Brewster window are presented. Excitation of several modes at 1 MW power level in the range of frequencies from 131 to 146.5 GHz is achieved. (author)

  16. Electro-mechanically induced GHz rate optical frequency modulation in silicon

    Tallur, Siddharth

    2012-01-01

    We present a monolithic silicon acousto-optic frequency modulator (AOFM) operating at 1.09GHz. Direct spectroscopy of the modulated laser power shows asymmetric sidebands which indicate coincident amplitude modulation and frequency modulation. Employing mechanical levers to enhance displacement of the optical resonator resulted in greater than 67X improvement in the opto-mechanical frequency modulation factor over earlier reported numbers for silicon nanobeams.

  17. 22.8 GHz Substrate Integrated Waveguide Analog Frequency Divide-by-3 Circuit

    Georgiadis, Apostolos; Collado, Ana; Niotaki, Kyriaki

    2015-01-01

    A 22.8 GHz analog frequency divide-by-3 circuit is presented based on an injection locked oscillator. Substrate integrated waveguide (SIW) technology is used to implement the input and output sections of the frequency divider circuit. The input SIW section at the gate of the active device permits the introduction of the injection signal at the third harmonic frequency of the oscillator, while the output section is designed to maximize the DC-RF conversion efficiency of the oscillator circuit....

  18. Frequency stability of InP HBT over 0.2 to 220 GHz

    Zhijiang, Zhou; Kun, Ren; Jun, Liu; Wei, Cheng; Haiyan, Lu; Lingling, Sun

    2015-02-01

    The frequency stabilities of InP DHBTs in a broadband over 1 to 220 GHz are investigated. A hybrid π-topology small-signal model is used to accurately capture the parasitics of devices. The model parameters are extracted from measurements analytically. The investigation results show that the excellent agreement between the measured and simulated data is obtained in the frequency range 200 MHz to 220 GHz. The dominant parameters of the π-topology model, bias conditions and emitter area have significant effects on the stability factor K. The HBT model can be unconditionally stable by reasonable selection of the proper bias condition and the physical layout of the device.

  19. A fully-differential phase-locked loop frequency synthesizer for 60-GHz wireless communication

    A 40-GHz phase-locked loop (PLL) frequency synthesizer for 60-GHz wireless communication applications is presented. The electrical characteristics of the passive components in the VCO and LO buffers are accurately extracted with an electromagnetic simulator HFSS. A differential tuning technique is utilized in the voltage controlled oscillator (VCO) to achieve higher common-mode noise rejection and better phase noise performance. The VCO and the divider chain are powered by a 1.0 V supply while the phase-frequency detector (PFD) and the charge pump (CP) are powered by a 2.5 V supply to improve the linearity. The measurement results show that the total frequency locking range of the frequency synthesizer is from 37 to 41 GHz, and the phase noise from a 40 GHz carrier is −97.2 dBc/Hz at 1 MHz offset. Implemented in 65 nm CMOS, the synthesizer consumes a DC power of 62 mW, including all the buffers. (semiconductor integrated circuits)

  20. Design of Miniature Patch Antenna Around the Frequency 3.5 GHz for WIMAX Technology

    Adnane Latif

    2012-01-01

    This work aims to study a miniature rectangular patch antenna and#955; / 8 fed by coaxial probe with the transmission line method (TLM). The design and simulation of this antenna is around the frequency of 3.5GHz, for WIMAX technology. The results obtained (input impedance, reflection coefficient, VSWR and bandwidth) are given by the program in the software MATLAB.

  1. 60 GHz antenna measurement setup using a VNA without external frequency conversion

    Popa, Paula Irina; Pivnenko, Sergey; Nielsen, Jeppe Majlund;

    2014-01-01

    alternative solution which makes use of a standard wideband VNA without external frequency conversion units. The operational capability of the Planar Near-Field (PNF) Antenna Measurement Facility at the Technical University of Denmark was recently extended to 60 GHz employing an Agilent E8361A VNA (up to 67...

  2. Design of Miniature Patch Antenna Around the Frequency 3.5 GHz for WIMAX Technology

    Adnane Latif

    2012-01-01

    Full Text Available This work aims to study a miniature rectangular patch antenna and#955; / 8 fed by coaxial probe with the transmission line method (TLM. The design and simulation of this antenna is around the frequency of 3.5GHz, for WIMAX technology. The results obtained (input impedance, reflection coefficient, VSWR and bandwidth are given by the program in the software MATLAB.

  3. Laser offset-frequency locking up to 20 GHz using a low-frequency electrical filter technique

    Schilt, Stephane; Matthey, Renaud; Kauffmann-Werner, Daniela; Affolderbach, Christoph; Mileti, Gaetano; Thévenaz, Luc

    2008-01-01

    A simple, easy-to-implement, and robust technique is reported to offset lock two semiconductor lasers with a frequency difference easily adjustable up to a couple of tens of gigahertz (10 and 19 GHz experimentally demonstrated). The proposed scheme essentially makes use of low-frequency control electronics and may be implemented with any type of single mode semiconductor laser, without any requirement for the laser linewidth. The technique is shown to be very similar to the wavelength modulat...

  4. Experimental Demonstration and Theoretical Analysis of Slow Light in a Semiconductor Waveguide at GHz Frequencies

    Mørk, Jesper; Kjær, Rasmus; Poel, Mike van der;

    2005-01-01

    Experimental demonstration and theoretical analysis of slow light in a semiconductor waveguide at GHz frequencies slow-down of light by a factor of two in a semiconductor waveguide at room temperature with a bandwidth of 16.7 GHz using the effect of coherent pulsations of the carrier density. The...... achievable delay is shown to be limited by the short lifetime. The maximum time delay observed reflects an approximately two-fold increase of the group refractive index, corresponding to a time delay of approximately 20 % of the carrier (population) lifetime. The experimental observations are well-explained...

  5. Wavelength-sized GaAs optomechanical resonators with GHz frequency

    Ding, Lu; Senellart, Pascale; Lemaitre, Aristide; Ducci, Sara; Leo, Giuseppe; Favero, Ivan

    2011-01-01

    We report on wavelength-sized GaAs optomechanical disk resonators showing ultra-strong optomechanical interaction. We observe optical transduction of a disk mechanical breathing mode with 1.4 GHz frequency and effective mass of ~ 2 pg. The measured vacuum optomechanical coupling rate reaches 0.8 MHz, with a related differential optomechanical coupling factor of 485 GHz/nm. The disk Brownian motion is optically resolved with a sensitivity of 10-17 m/{\\sqrt}Hz at room temperature and pressure.

  6. Sustaining GHz oscillation of carbon nanotube based oscillators via a MHz frequency excitation

    Motevalli, Benyamin; Taherifar, Neda; Zhe Liu, Jefferson

    2016-05-01

    There have been intensive studies to investigate the properties of gigahertz nano-oscillators based on multi-walled carbon nanotubes (MWCNTs). Many of these studies, however, revealed that the unique telescopic translational oscillations in such devices would damp quickly due to various energy dissipation mechanisms. This challenge remains the primary obstacle against its practical applications. Herein, we propose a design concept in which a GHz oscillation could be re-excited by a MHz mechanical motion. This design involves a triple-walled CNT, in which sliding of the longer inner tube at a MHz frequency can re-excite and sustain a GHz oscillation of the shorter middle tube. Our molecular dynamics (MD) simulations prove this design concept at ∼10 nm scale. A mathematical model is developed to explore the feasibility at a larger size scale. As an example, in an oscillatory system with the CNT’s length above 100 nm, the high oscillatory frequency range of 1.8–3.3 GHz could be excited by moving the inner tube at a much lower frequency of 53.4 MHz. This design concept together with the mechanical model could energize the development of GHz nano-oscillators in miniaturized electro-mechanical devices.

  7. Effects of microwave frequency of fine tuning on the performance of JYFL 14 GHz ECRIS

    Measurements have been carried out to study the effects of microwave frequency fine tuning on the performance of JYFL 14 GHz electron cyclotron resonance ion source. The frequency was varied within an 85 MHz band around the normal operation frequency of 14.085 GHz. The radial Bremsstrahlung emission was measured for plasma diagnostics purposes and mass separated ion beam currents extracted from the ion source were recorded at the same time. Also, beam quality studies were conducted by measuring the ion beam emittance and shape with and without enhanced space charge compensation achieved by increased neutral gas pressure in the beam line. The studies presented in this article show that microwave frequency fine tuning does produce clear variations to many of the measurable quantities connected to the performance of the JYFL 14 GHz ECRIS. However, the varying input power makes it difficult to separate which effects are caused by the frequency variations and not the power fluctuations. This is the case especially with the beam currents. The beam emittance and profile exhibited clear variations which were further strengthened with the ESCC. These effects on the beam quality were clearly reflected as significant variations in the transmission efficiency. The paper is followed by the associated poster

  8. The functional correlation between rainfall rate and extinction coefficient for frequencies from 3 to 10 GHz

    Jameson, A. R.

    1990-01-01

    The relationship between the rainfall rate (R) obtained from radiometric brightness temperatures and the extinction coefficient (k sub e) is investigated by computing the values of k sub e over a wide range of rainfall rates, for frequencies from 3 to 25 GHz. The results show that the strength of the relation between the R and the k sub e values exhibits considerable variation for frequencies at this range. Practical suggestions are made concerning the selection of particular frequencies for rain measurements to minimize the error in R determinations.

  9. Frequency stability of InP HBT over 0.2 to 220 GHz

    The frequency stabilities of InP DHBTs in a broadband over 1 to 220 GHz are investigated. A hybrid π-topology small-signal model is used to accurately capture the parasitics of devices. The model parameters are extracted from measurements analytically. The investigation results show that the excellent agreement between the measured and simulated data is obtained in the frequency range 200 MHz to 220 GHz. The dominant parameters of the π-topology model, bias conditions and emitter area have significant effects on the stability factor K. The HBT model can be unconditionally stable by reasonable selection of the proper bias condition and the physical layout of the device. (semiconductor devices)

  10. RF and GIS: Field Strength Prediction for Frequencies between 900 MHz and 28 GHz.

    Baldassaro, Paige Marie

    2001-01-01

    This thesis presents a model to predict signal strength for frequencies between 902 MHz and 28 GHz. The model approximates diffraction using the knife-edge concept and equations proposed by Lee (1985). LOS pathways are calculated using the Bresenham algorithm and the corresponding elevations are obtained from a 30m DEM base map. The base map was generated by the procedure outlined in Rose (2001) and includes building elevations. The effect of Fresnel zones on prediction accuracy is consid...

  11. The highest frequency detection of a radio relic: 16 GHz AMI observations of the `Sausage' cluster

    Stroe, Andra; Rumsey, Clare; Harwood, Jeremy J.; van Weeren, Reinout J.; Röttgering, Huub J. A.; Saunders, Richard D. E.; Sobral, David; Perrott, Yvette C.; Schammel, Michel P.

    2014-06-01

    We observed the cluster CIZA J2242.8+5301 with the Arcminute Microkelvin Imager at 16 GHz and present the first high radio-frequency detection of diffuse, non-thermal cluster emission. This cluster hosts a variety of bright, extended, steep-spectrum synchrotron-emitting radio sources, associated with the intracluster medium, called radio relics. Most notably, the northern, Mpc-wide, narrow relic provides strong evidence for diffusive shock acceleration in clusters. We detect a puzzling, flat-spectrum, diffuse extension of the southern relic, which is not visible in the lower radio-frequency maps. The northern radio relic is unequivocally detected and measures an integrated flux of 1.2 ± 0.3 mJy. While the low-frequency (<2 GHz) spectrum of the northern relic is well represented by a power law, it clearly steepens towards 16 GHz. This result is inconsistent with diffusive shock acceleration predictions of ageing plasma behind a uniform shock front. The steepening could be caused by an inhomogeneous medium with temperature/density gradients or by lower acceleration efficiencies of high energy electrons. Further modelling is necessary to explain the observed spectrum.

  12. Development of a dual frequency (110/138 GHz gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

    Kobayashia Takayuki

    2015-01-01

    Full Text Available A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH and current drive (ECCD in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both frequencies. Cooling water temperatures in the gyrotron and matching optics unit were saturated in the 198 s oscillation, and the observed maximum water temperature is sufficiently low. In addition to the above activity on the dual-frequency gyrotron development, an oscillation (0.3 MW for 20 ms at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron. A possibility of the use of fundamental harmonic wave at 82 GHz in JT-60SA has been shown.

  13. The widest frequency radio relic spectra: observations from 150 MHz to 30 GHz

    Stroe, Andra; Shimwell, Timothy; Rumsey, Clare; van Weeren, Reinout; Kierdorf, Maja; Donnert, Julius; Jones, Thomas W.; Röttgering, Huub J. A.; Hoeft, Matthias; Rodríguez-Gonzálvez, Carmen; Harwood, Jeremy J.; Saunders, Richard D. E.

    2016-01-01

    Radio relics are patches of diffuse synchrotron radio emission that trace shock waves. Relics are thought to form when intracluster medium electrons are accelerated by cluster merger-induced shock waves through the diffusive shock acceleration mechanism. In this paper, we present observations spanning 150 MHz to 30 GHz of the `Sausage' and `Toothbrush' relics from the Giant Metrewave and Westerbork telescopes, the Karl G. Jansky Very Large Array, the Effelsberg telescope, the Arcminute Microkelvin Imager and Combined Array for Research in Millimeter-wave Astronomy. We detect both relics at 30 GHz, where the previous highest frequency detection was at 16 GHz. The integrated radio spectra of both sources clearly steepen above 2 GHz, at the ≳6σ significance level, supporting the spectral steepening previously found in the `Sausage' and the Abell 2256 relic. Our results challenge the widely adopted simple formation mechanism of radio relics and suggest more complicated models have to be developed that, for example, involve re-acceleration of aged seed electrons.

  14. A 23.75-GHz frequency comb with two low-finesse filtering cavities in series for high resolution spectroscopy

    侯磊; 韩海年; 王薇; 张龙; 庞利辉; 李德华; 魏志义

    2015-01-01

    A laser frequency comb with several tens GHz level is demonstrated, based on an Yb-doped femtosecond fiber laser and two low-finesse Fabry–P´erot cavities (FPCs) in series. The original 250-MHz mode-line-spacing of the source comb is filtered to 4.75 GHz and 23.75 GHz, respectively. According to the multi-beam interferences theory of FPC, the side-mode suppression rate of FPC schemes is in good agreement with our own theoretical results from 27 dB of a single FPC to 43 dB of paired FPCs. To maintain long-term stable operation and determine the absolute frequency mode number in the 23.75-GHz comb, the Pound–Drever–Hall (PDH) locking technology is utilized. Such stable tens GHz frequency combs have important applications in calibrating astronomical spectrographs with high resolution.

  15. A 23.75-GHz frequency comb with two low-finesse filtering cavities in series for high resolution spectroscopy

    A laser frequency comb with several tens GHz level is demonstrated, based on a Yb-doped femtosecond fiber laser and two low-finesse Fabry–Pérot cavities (FPCs) in series. The original 250-MHz mode-line-spacing of the source comb is filtered to 4.75 GHz and 23.75 GHz, respectively. According to the multi-beam interferences theory of FPC, the side-mode suppression rate of FPC schemes is in good agreement with our own theoretical results from 27 dB of a single FPC to 43 dB of paired FPCs. To maintain long-term stable operation and determine the absolute frequency mode number in the 23.75-GHz comb, the Pound–Drever–Hall (PDH) locking technology is utilized. Such stable tens GHz frequency combs have important applications in calibrating astronomical spectrographs with high resolution. (paper)

  16. High-Frequency Wireless Communications System: 2.45-GHz Front-End Circuit and System Integration

    Chen, M.-H.; Huang, M.-C.; Ting, Y.-C.; Chen, H.-H.; Li, T.-L.

    2010-01-01

    In this article, a course on high-frequency wireless communications systems is presented. With the 145-MHz baseband subsystem available from a prerequisite course, the present course emphasizes the design and implementation of the 2.45-GHz front-end subsystem as well as system integration issues. In this curriculum, the 2.45-GHz front-end…

  17. Mechanically robust 39 GHz cut-off frequency graphene field effect transistors on flexible substrates.

    Wei, Wei; Pallecchi, Emiliano; Haque, Samiul; Borini, Stefano; Avramovic, Vanessa; Centeno, Alba; Amaia, Zurutuza; Happy, Henri

    2016-08-01

    Graphene has been regarded as a promising candidate channel material for flexible devices operating at radio-frequency (RF). In this work we fabricated and fully characterized double bottom-gate graphene field effect transistors on flexible polymer substrates for high frequency applications. We report a record high as-measured current gain cut-off frequency (ft) of 39 GHz. The corresponding maximum oscillation frequency (fmax) is 13.5 GHz. These state of the art high frequency performances are stable against bending, with a typical variation of around 10%, for a bending radius of up to 12 mm. To demonstrate the reliability of our devices, we performed a fatigue stress test for RF-GFETs which were dynamically bend tested 1000 times at 1 Hz. The devices are mechanically robust, and performances are stable with typical variations of 15%. Finally we investigate thermal dissipation, which is a critical parameter for flexible electronics. We show that at the optimum polarization the normalized power dissipated by the GFETs is about 0.35 mW μm(-2) and that the substrate temperature is around 200 degree centigrade. At a higher power, irreversible degradations of the performances are observed. Our study on state of the art flexible GFETs demonstrates mechanical robustness and stability upon heating, two important elements to assess the potential of GFETs for flexible electronics. PMID:27396243

  18. Underwater Wireless Sensor Communications in the 2.4 GHz ISM Frequency Band

    Joel J. P. C. Rodrigues

    2012-03-01

    Full Text Available One of the main problems in underwater communications is the low data rate available due to the use of low frequencies. Moreover, there are many problems inherent to the medium such as reflections, refraction, energy dispersion, etc., that greatly degrade communication between devices. In some cases, wireless sensors must be placed quite close to each other in order to take more accurate measurements from the water while having high communication bandwidth. In these cases, while most researchers focus their efforts on increasing the data rate for low frequencies, we propose the use of the 2.4 GHz ISM frequency band in these special cases. In this paper, we show our wireless sensor node deployment and its performance obtained from a real scenario and measures taken for different frequencies, modulations and data transfer rates. The performed tests show the maximum distance between sensors, the number of lost packets and the average round trip time. Based on our measurements, we provide some experimental models of underwater communication in fresh water using EM waves in the 2.4 GHz ISM frequency band. Finally, we compare our communication system proposal with the existing systems. Although our proposal provides short communication distances, it provides high data transfer rates. It can be used for precision monitoring in applications such as contaminated ecosystems or for device communicate at high depth.

  19. Underwater wireless sensor communications in the 2.4 GHz ISM frequency band.

    Lloret, Jaime; Sendra, Sandra; Ardid, Miguel; Rodrigues, Joel J P C

    2012-01-01

    One of the main problems in underwater communications is the low data rate available due to the use of low frequencies. Moreover, there are many problems inherent to the medium such as reflections, refraction, energy dispersion, etc., that greatly degrade communication between devices. In some cases, wireless sensors must be placed quite close to each other in order to take more accurate measurements from the water while having high communication bandwidth. In these cases, while most researchers focus their efforts on increasing the data rate for low frequencies, we propose the use of the 2.4 GHz ISM frequency band in these special cases. In this paper, we show our wireless sensor node deployment and its performance obtained from a real scenario and measures taken for different frequencies, modulations and data transfer rates. The performed tests show the maximum distance between sensors, the number of lost packets and the average round trip time. Based on our measurements, we provide some experimental models of underwater communication in fresh water using EM waves in the 2.4 GHz ISM frequency band. Finally, we compare our communication system proposal with the existing systems. Although our proposal provides short communication distances, it provides high data transfer rates. It can be used for precision monitoring in applications such as contaminated ecosystems or for device communicate at high depth. PMID:22666029

  20. Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

    Kobayashia Takayuki; Moriyama Shinichi; Isayama Akihiko; Sawahata Masayuki; Terakado Masayuki; Hiranai Shinichi; Wada Kenji; Sato Yoshikatsu; Hinata Jun; Yokokura Kenji; Hoshino Katsumichi; Sakamoto Keishi

    2015-01-01

    A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both fre...

  1. a New Broadband Cavity Enhanced Frequency Comb Spectroscopy Technique Using GHz Vernier Filtering.

    Morville, Jérôme; Rutkowski, Lucile; Dobrev, Georgi; Crozet, Patrick

    2015-06-01

    We present a new approach to Cavity Enhanced - Direct Frequency Comb Spectroscopy where the full emission bandwidth of a Titanium:Sapphire laser is exploited at GHz resolution. The technique is based on a low-resolution Vernier filtering obtained with an appreciable -actively stabilized- mismatch between the cavity Free Spectral Range and the laser repetition rate, using a diffraction grating and a split-photodiode. This particular approach provides an immunity to frequency-amplitude noise conversion, reaching an absorption baseline noise in the 10-9 cm-1 range with a cavity finesse of only 3000. Spectra covering 1800 cm-1 (˜ 55 THz) are acquired in recording times of about 1 second, providing an absorption figure of merit of a few 10-11 cm-1/√{Hz}. Initially tested with ambient air, we report progress in using the Vernier frequency comb method with a discharge source of small radicals. Rutkowski et al, Opt. Lett., 39(23)2014

  2. 64 Gbit/s Transmission over 850 m Fixed Wireless Link at 240 GHz Carrier Frequency

    Kallfass, Ingmar; Boes, Florian; Messinger, Tobias; Antes, Jochen; Inam, Anns; Lewark, Ulrich; Tessmann, Axel; Henneberger, Ralf

    2015-02-01

    A directive fixed wireless link operating at a center frequency of 240 GHz achieves a data rate of 64 Gbit/s over a transmission distance of 850 m using QPSK and 8PSK modulation, in a single-channel approach without the use of spatial diversity concepts. The analog transmit and receive frontend consists of active monolithic integrated circuits including broadband RF amplification and quadrature subharmonic mixer channels. The analog frontend is addressed by 64 GSa/s ADC and DAC boards, which are amenable to real-time data transmission. A link budget calculation allows for the estimation of the performance under adverse weather conditions.

  3. Electromagnetic interference shielding effectiveness of composite carbon nanotube macro-film at a high frequency range of 40 GHz to 60 GHz

    Zi Ping Wu

    2015-06-01

    Full Text Available The electromagnetic interference (EMI shielding effectiveness (SE of carbon nanotube (CNT macro-film that is adhered to common cloth to maintain the light weight, silk-like quality, and smooth surface of the material for EMI shielding is investigated. The results show that a high and stable EMI SE of 48 dB to 57 dB at 40 GHz to 60 GHz was obtained by the macro-film with a thickness of only ∼4 μm. The composite CNT macro-film is easily manipulated, and its EMI property is significantly different from that of traditional electromagnetic shielding materials that show a lower EMI SE with increasing frequency. For example, the EMI SE of Cu foils decrease from 75 dB to 35 dB as frequency increases from 25 GHz to 60 GHz. Considering their stable and outstanding EMI SE and easy manipulation, the composite CNT macro-films are expected to have potential applications in shielding against millimeter waves.

  4. Mechanically robust 39 GHz cut-off frequency graphene field effect transistors on flexible substrates

    Wei, Wei; Pallecchi, Emiliano; Haque, Samiul; Borini, Stefano; Avramovic, Vanessa; Centeno, Alba; Amaia, Zurutuza; Happy, Henri

    2016-07-01

    Graphene has been regarded as a promising candidate channel material for flexible devices operating at radio-frequency (RF). In this work we fabricated and fully characterized double bottom-gate graphene field effect transistors on flexible polymer substrates for high frequency applications. We report a record high as-measured current gain cut-off frequency (ft) of 39 GHz. The corresponding maximum oscillation frequency (fmax) is 13.5 GHz. These state of the art high frequency performances are stable against bending, with a typical variation of around 10%, for a bending radius of up to 12 mm. To demonstrate the reliability of our devices, we performed a fatigue stress test for RF-GFETs which were dynamically bend tested 1000 times at 1 Hz. The devices are mechanically robust, and performances are stable with typical variations of 15%. Finally we investigate thermal dissipation, which is a critical parameter for flexible electronics. We show that at the optimum polarization the normalized power dissipated by the GFETs is about 0.35 mW μm-2 and that the substrate temperature is around 200 degree centigrade. At a higher power, irreversible degradations of the performances are observed. Our study on state of the art flexible GFETs demonstrates mechanical robustness and stability upon heating, two important elements to assess the potential of GFETs for flexible electronics.Graphene has been regarded as a promising candidate channel material for flexible devices operating at radio-frequency (RF). In this work we fabricated and fully characterized double bottom-gate graphene field effect transistors on flexible polymer substrates for high frequency applications. We report a record high as-measured current gain cut-off frequency (ft) of 39 GHz. The corresponding maximum oscillation frequency (fmax) is 13.5 GHz. These state of the art high frequency performances are stable against bending, with a typical variation of around 10%, for a bending radius of up to 12 mm. To

  5. Design and Characterization of a 5.2 GHz/2.4 GHz ΣΔ Fractional- N Frequency Synthesizer for Low-Phase Noise Performance

    2006-01-01

    Full Text Available This paper presents a complete noise analysis of a ΣΔ -based fractional- N phase-locked loop (PLL based frequency synthesizer. Rigorous analytical and empirical formulas have been given to model various phase noise sources and spurious components and to predict their impact on the overall synthesizer noise performance. These formulas have been applied to an integrated multiband WLAN frequency synthesizer RFIC to demonstrate noise minimization through judicious choice of loop parameters. Finally, predicted and measured phase jitter showed good agreement. For an LO frequency of 4.3 GHz, predicted and measured phase noise was 0.50 ° rms and 0.535 ° rms, respectively.

  6. Performance Analysis of Multiple Access 60 GHz System Using Frequency-shifted Gaussian Pulse and Non-carrier PSWF Pulse

    Hao Zhang; Wei Shi; Tingting Lu; Jingjing Wang; Xinjie Wang

    2013-01-01

    In this paper, a kind of impulse radio (IR) 60 GHz pulse based on Prolate Spheroidal Wave Functions (PSWF) is proposed. The capacity and performance for multiple access 60 GHz communication system based on carrier pulse and impulse radio pulse are analyzed separately. Both frequency-shifted Gaussian pulse and Prolate Spheroidal Wave Functions (PSWF) pulse are considered and devised according to the federal communication commission (FCC) power constraints. Pulse position modulation (PPM) with ...

  7. Design of a 2.4-GHz CMOS monolithic fractional-N frequency synthesizer

    Shu, Keliu

    The wireless communication technology and market have been growing rapidly since a decade ago. The high demand market is a driving need for higher integration in the wireless transceivers. The trend is to achieve low-cost, small form factor and low power consumption. With the ever-reducing feature size, it is becoming feasible to integrate the RF front-end together with the baseband in the low-cost CMOS technology. The frequency synthesizer is a key building block in the RF front-end of the transceivers. It is used as a local oscillator for frequency translation and channel selection. The design of a 2.4-GHz low-power frequency synthesizer in 0.35mum CMOS is a challenging task mainly due to the high-speed prescaler. In this dissertation, a brief review of conventional PLL and frequency synthesizers is provided. Design techniques of a 2.4-GHz monolithic SigmaDelta fractional-N frequency synthesizer are investigated. Novel techniques are proposed to tackle the speed and integration bottlenecks of high-frequency PLL. A low-power and inherently glitch-free phase-switching prescaler and an on-chip loop filter with capacitance multiplier are developed. Compared with the existing and popular dual-path topology, the proposed loop filter reduces circuit complexity and its power consumption and noise are negligible. Furthermore, a third-order three-level digital SigmaDelta modulator topology is employed to reduce the phase noise generated by the modulator. Suitable PFD and charge-pump designs are employed to reduce their nonlinearity effects and thus minimize the folding of the SigmaDelta modulator-shaped phase noise. A prototype of the fractional-N synthesizer together with some standalone building blocks is designed and fabricated in TSMC 0.35mum CMOS through MOSIS. The prototype frequency synthesizer and standalone prescaler and loop filter are characterized. The feasibility and practicality of the proposed prescaler and loop filter are experimentally verified.

  8. Time-Resolved SQUID Sensor with a Nyquist Frequency up to 25 GHz

    Cui, Z.; Wang, Y. H.; Kratz, P.; Rosenberg, A. J.; Watson, C. A.; Sochnikov, I.; Fung, Y.-K.-K.; Gibson, G.; Kirtley, J. R.; Ketchen, M. B.; Moler, K. A.

    We demonstrate a time-resolved scanning Superconducting QUantum Interference Device (SQUID) sensor with an expected maximum sampling rate of 50 GHz. The time-resolved SQUID sampler is operated by a pump-probe pulse sequence and will be particularly useful in studying high-frequency magnetic devices and the transient behavior of magnetic materials. The high sampling rate is achieved through a Josephson-interferometry technique developed at IBM. We tested our sampler with flux signals of order 10 mΦ0 (where Φ0 is the magnetic flux quantum), which corresponds to 25 million Bohr magnetons located 1 micron directly below the pickup loop. Operating in this regime, our sampler will have much higher sensitivity than bulk sensors like conventional SQUIDs and much larger spatial scanning range than single-spin sensors like NV centers. The SQUID sampler will thus be well-suited to characterize individual mesoscopic samples as well as bulk samples with mesoscopic features.

  9. A 0.8–4.2 GHz monolithic all-digital PLL based frequency synthesizer for wireless communications

    A 0.8–4.2 GHz monolithic all-digital PLL based frequency synthesizer for wireless communications is successfully realized by the 130 nm CMOS process. A series of novel methods are proposed in this paper. Two band DCOs with high frequency resolution are utilized to cover the frequency band of interest, which is as wide as 2.5 to 5 GHz. An overflow counter is proposed to prevent the “pulse-swallowing” phenomenon so as to significantly reduce the locking time. A NTW-clamp digital module is also proposed to prevent the overflow of the loop control word. A modified programmable divider is presented to prevent the failure operation at the boundary. The measurement results show that the output frequency range of this frequency synthesizer is 0.8–4.2 GHz. The locking time achieves a reduction of 84% at 2.68 GHz. The best in-band and out-band phase noise performances have reached −100 dBc/Hz, and −125 dBc/Hz respectively. The lowest reference spur is −58 dBc. (semiconductor integrated circuits)

  10. Design, development, and verification of the Planck Low Frequency Instrument 70 GHz Front-End and Back-End Modules

    70 GHz radiometer front-end and back-end modules for the Low Frequency Instrument of the European Space Agency's Planck Mission were built and tested. The operating principles and the design details of the mechanical structures are described along with the key InP MMIC low noise amplifiers and phase switches of the units. The units were tested in specially designed cryogenic vacuum chambers capable of producing the operating conditions required for Planck radiometers, specifically, a physical temperature of 20 K for the front-end modules, 300 K for the back-end modules and 4 K for the reference signal sources. Test results of the low noise amplifiers and phase switches, the front and back-end modules, and the combined results of both modules are discussed. At 70 GHz frequency, the system noise temperature of the front and back end is 28 K; the effective bandwidth 16 GHz, and the 1/f spectrum knee frequency is 38 mHz.The test results indicate state-of-the-art performance at 70 GHz frequency and fulfil the Planck performance requirements.

  11. Design, development, and verification of the Planck Low Frequency Instrument 70 GHz Front-End and Back-End Modules

    Varis, J; Laaninen, M; Kilpia, V -H; Jukkala, P; Tuovinen, J; Ovaska, S; Sjoman, P; Kangaslahti, P; Gaier, T; Hoyland, R; Meinhold, P; Mennella, A; Bersanelli, M; Butler, R C; Cuttaia, F; Franceschi, E; Leonardi, R; Leutenegger, P; Malaspina, M; Mandolesi, N; Miccolis, M; Poutanen, T; Kurki-Suonio, H; Sandri, M; Stringhetti, L; Terenzi, L; Tomasi, M; Valenziano, L; 10.1088/1748-0221/4/12/T12001

    2010-01-01

    70 GHz radiometer front-end and back-end modules for the Low Frequency Instrument of the European Space Agencys Planck Mission were built and tested. The operating principles and the design details of the mechanical structures are described along with the key InP MMIC low noise amplifiers and phase switches of the units. The units were tested in specially designed cryogenic vacuum chambers capable of producing the operating conditions required for Planck radiometers, specifically, a physical temperature of 20 K for the front-end modules, 300 K for the back-end modules and 4 K for the reference signal sources. Test results of the low noise amplifiers and phase switches, the front and back-end modules, and the combined results of both modules are discussed. At 70 GHz frequency, the system noise temperature of the front and back end is 28 K; the effective bandwidth 16 GHz, and the 1/f spectrum knee frequency is 38 mHz. The test results indicate state-of-the-art performance at 70 GHz frequency and fulfil the Plan...

  12. Digital coherent detection of multi-gigabit 40 GHz carrier frequency radio-over-fibre signals using photonic downconversion

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    2010-01-01

    Detection of high-speed radio signals is a challenge for next generation radio-over-fibre links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, detection of high bit-rate 16-QAM signals, up to 4 Gbit/s, at a 40 GHz carrier frequency...

  13. Frequency and Path Length Scaling of Rain Attenuation from 38 GHz, 58 GHz and 93 GHz Data Obtained on Terrestrial Paths

    Kvičera, V.; Grábner, M.; Fišer, Ondřej

    New York: IEEE, 2009, s. 2546-2550. ISBN 978-1-4244-4753-4. [European Conference on Antennas and Propagation /3./. Berlin (DE), 22.03.2009-27.03.2009] Grant ostatní: GA Mšk(CZ) OC 093 Institutional research plan: CEZ:AV0Z30420517 Keywords : rain attenuation * frequency scaling * path scaling * HAPs Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  14. Fine resolution calculations of SAR in the human body for frequencies up to 3 GHz

    Dimbylow, P. J.

    2002-08-01

    Finite-difference time-domain (FDTD) calculations of whole-body averaged specific energy absorption rate (SAR) have been performed from 100 MHz to 3 GHz at the basic 2 mm resolution of the voxel (volume pixel) model NORMAN without any rescaling to larger cell sizes. The reduction in the voxel size from previous work allows SAR to be calculated at higher frequencies. Additionally, the calculations have been extended down to 10 MHz, covering the whole-body resonance regions at a resolution of 4 mm. As well as for the adult phantom, SAR values are calculated for scaled versions representing 10-, 5- and 1-year-old children for both grounded and isolated conditions. External electric field levels are derived from limits of whole-body averaged SAR and localized SAR in the ankle, and compared with NRPB investigation levels and ICNIRP reference levels. The ICNIRP field reference levels alone would not provide a conservative estimate of the localized SAR exposure in the leg for grounded conditions. It would be necessary to invoke the secondary reference level on limb current to provide compliance with basic restrictions on localized SAR averaged over 10 g.

  15. A 4 GHz 32 bit direct digital frequency synthesizer based on a novel architecture

    This paper presents a novel direct digital frequency synthesizer (DDFS) architecture based on nonlinear DAC coarse quantization and the ROM-based piecewise approximation method, which has the advantages of high speed, low power and low hardware resources. By subdividing the sinusoid into a collection of phase segments, the same initial value of each segment is realized by a nonlinear DAC. The ROM is decomposed with a coarse ROM and fine ROM using the piecewise approximation method. Then, the coarse ROM stores the offsets between the initial value of the common segment and the initial value of each line in the same segment. Meanwhile, the fine ROM stores the differences between the line values and the initial value of each line. A ROM compression ratio of 32 can be achieved in the case of 11 bit phase and 9 bit amplitude. Based on the above method, a prototype chip was fabricated using 1.4 μm GaAs HBT technology. The measurement shows an average spurious-free dynamic range (SFDR) of 45 dBc, with the worst SFDR only 40.07 dBc at a 4.0 GHz clock. The chip area is 4.6 × 3.7 mm2 and it consumes 7 W from a −4.9 V power supply. (semiconductor integrated circuits)

  16. A 4 GHz 32 bit direct digital frequency synthesizer based on a novel architecture

    Jin, Wu; Jianwu, Chen; Danyu, Wu; Lei, Zhou; Fan, Jiang; Zhi, Jin; Xinyu, Liu

    2013-11-01

    This paper presents a novel direct digital frequency synthesizer (DDFS) architecture based on nonlinear DAC coarse quantization and the ROM-based piecewise approximation method, which has the advantages of high speed, low power and low hardware resources. By subdividing the sinusoid into a collection of phase segments, the same initial value of each segment is realized by a nonlinear DAC. The ROM is decomposed with a coarse ROM and fine ROM using the piecewise approximation method. Then, the coarse ROM stores the offsets between the initial value of the common segment and the initial value of each line in the same segment. Meanwhile, the fine ROM stores the differences between the line values and the initial value of each line. A ROM compression ratio of 32 can be achieved in the case of 11 bit phase and 9 bit amplitude. Based on the above method, a prototype chip was fabricated using 1.4 μm GaAs HBT technology. The measurement shows an average spurious-free dynamic range (SFDR) of 45 dBc, with the worst SFDR only 40.07 dBc at a 4.0 GHz clock. The chip area is 4.6 × 3.7 mm2 and it consumes 7 W from a -4.9 V power supply.

  17. Coherent continuous-wave dual-frequency high-Q external-cavity semiconductor laser for GHz-THz applications.

    Paquet, Romain; Blin, Stéphane; Myara, Mikhaël; Gratiet, Luc Le; Sellahi, Mohamed; Chomet, Baptiste; Beaudoin, Grégoire; Sagnes, Isabelle; Garnache, Arnaud

    2016-08-15

    We report a continuous-wave highly-coherent and tunable dual-frequency laser emitting at two frequencies separated by 30 GHz to 3 THz, based on compact III-V diode-pumped quantum-well surface-emitting semiconductor laser technology. The concept is based on the stable simultaneous operation of two Laguerre-Gauss transverse modes in a single-axis short cavity, using an integrated sub-wavelength-thick metallic mask. Simultaneous operation is demonstrated theoretically and experimentally by recording intensity noises and beat frequency, and time-resolved optical spectra. We demonstrated a >80  mW output power, diffraction-limited beam, narrow linewidth of 45  dB), and low intensity noise class-A dynamics of <0.3% rms, thus opening the path to a compact low-cost coherent GHz to THz source development. PMID:27519080

  18. Experimental investigation of a novel microchip laser producing synchronized dual-frequency laser pulse with an 85 GHz interval

    A novel self-Q-switched microchip laser is introduced, which can produce synchronized dual-frequency laser pulse trains. By adopting a prepump mechanism, as well as shifting the gain curve and resonance wavelengths, the relative gains of π and σ polarization modes are adjusted, which offers an effective way to finely synchronize the laser pulses. By employing a 0.9 mm length monolithic cavity, a pair of synchronized pulse trains with a frequency separation of 85 GHz (0.32 nm) is achieved, which nearly approaches the gain bandwidth of the laser medium. Another separated cavity with a length of 2.8 mm operates in the same way for further investigation of microwave generation. A radiofrequency signal with frequency of 26.565 GHz is achieved by beat-noting of the synchronized laser pulse trains with 0.1 nm wavelength separation. (letter)

  19. The Power of Simultaneous Multi-Frequency Observations for mm-VLBI: Astrometry up to 130 GHz with the KVN

    Rioja, Maria J; Jung, Taehyun; Sohn, Bong Won

    2015-01-01

    Simultaneous observations at multiple frequencies have the potential to overcome the fundamental limitation imposed by the atmospheric propagation in mm-VLBI observations. The propagation effects place a severe limit in the sensitivity achievable in mm-VLBI, reducing the time over which the signals can be coherently combined, and preventing the use of phase referencing and astrometric measurements. We carried out simultaneous observations at 22, 43, 87 and 130\\,GHz of a group of five AGNs, the weakest of which is $\\sim$200\\,mJy at 130\\,GHz, with angular separations ranging from 3.6 to 11 degrees, with the KVN. We analysed this data using the Frequency Phase Transfer (FPT) and the Source Frequency Phase Referencing (SFPR) techniques, which use the observations at a lower frequency to correct those at a higher frequency. The results of the analysis provide an empirical demonstration of the increase in the coherence times at 130\\,GHz from a few tens of seconds to about twenty minutes, with FPT, and up to many ho...

  20. Forward and inverse dielectric modeling of oven-dried cement paste specimens in the frequency range of 1.02 GHz to 4.50 GHz

    Owusu Twumasi, Jones; Yu, Tzuyang

    2015-04-01

    The use of radar non-destructive evaluation (NDE) technique for condition assessment of deteriorated civil infrastructure systems is an effective approach for preserving the sustainability of these systems. Radar NDE utilizes the interaction between radar signals (electromagnetic waves) and construction materials for surface and subsurface sensing based on dielectric properties and geometry. In the success of radar inspection, it is imperative to develop models capable of predicting the dielectric properties of the materials under investigation. The dielectric properties (dielectric constant and loss factor) of oven-dried cement paste specimens with water-to-cement (w/c) ratios (0.35, 0.40, 0.45, 0.50, 0.55) in the frequency range of 1.02 GHz to 4.50 GHz were studied and modeled using modified Debye's models. An open-ended coaxial probe and a network analyzer were used to measure dielectric properties. Forward models are proposed and inversed for predicting the w/c ratio of a given oven-dried cement paste specimen. Modeling results agreed with the experimental data. The proposed models can be used for predicting the dielectric properties of oven-dried cement paste specimens. Also, the modeling approach can be applied to other cementitious materials (e.g., concrete) with additional modification.

  1. Atmospheric absorption model for dry air and water vapor at microwave frequencies below 100 GHz derived from spaceborne radiometer observations

    Wentz, Frank J.; Meissner, Thomas

    2016-05-01

    The Liebe and Rosenkranz atmospheric absorption models for dry air and water vapor below 100 GHz are refined based on an analysis of antenna temperature (TA) measurements taken by the Global Precipitation Measurement Microwave Imager (GMI) in the frequency range 10.7 to 89.0 GHz. The GMI TA measurements are compared to the TA predicted by a radiative transfer model (RTM), which incorporates both the atmospheric absorption model and a model for the emission and reflection from a rough-ocean surface. The inputs for the RTM are the geophysical retrievals of wind speed, columnar water vapor, and columnar cloud liquid water obtained from the satellite radiometer WindSat. The Liebe and Rosenkranz absorption models are adjusted to achieve consistency with the RTM. The vapor continuum is decreased by 3% to 10%, depending on vapor. To accomplish this, the foreign-broadening part is increased by 10%, and the self-broadening part is decreased by about 40% at the higher frequencies. In addition, the strength of the water vapor line is increased by 1%, and the shape of the line at low frequencies is modified. The dry air absorption is increased, with the increase being a maximum of 20% at the 89 GHz, the highest frequency considered here. The nonresonant oxygen absorption is increased by about 6%. In addition to the RTM comparisons, our results are supported by a comparison between columnar water vapor retrievals from 12 satellite microwave radiometers and GPS-retrieved water vapor values.

  2. Dielectric relaxation of binary polar liquid mixture measured in benzene at 10 GHz frequency

    S Sahoo; K Dutta; S Acharyya; S K Sit

    2008-03-01

    The dielectric relaxation times 's and dipole moments 's of the binary () polar liquid mixture of N,N-dimethyl acetamide (DMA) and acetone (Ac) dissolved in benzene (i) are estimated from the measured real ′ and imaginary ″ parts of complex high frequency conductivity * of the solution for different weight fractions 's of 0.0, 0.3, 0.5, 0.7 and 1.0 mole fractions of Ac and temperatures (25, 30, 35 and 40°C) respectively under 9.88 GHz electric field. 's are obtained from the ratio of slopes of ″ - and ′ - curves at → 0 as well as linear slope of ″ - ′ curves of the existing method (Murthy et al, 1989) in order to eliminate polar-polar interaction in the latter case. The calculated 's are in excellent agreement with the reported 's due to Gopalakrishna's method. 's are also estimated from slopes 's of total conductivity - curves at → 0 and the values agree well with the reported 's from G.K. method. The variation of 's and 's with of Ac reveals that solute-solute molecular association occurs within 0.0-0.3 of Ac beyond which solute-solvent molecular association is predicted. The theoretical dipole moments theo's are calculated from bond angles and bond moments to have exact 's only to show the presence of inductive, mesomeric and electromeric effects in the substituent polar groups. The thermodynamic energy parameters are estimated from ln () against 1/ linear curve from Eyring's rate theory to know the molecular dynamics of the system and to establish the fact that the mixture obeys the Debye-Smyth relaxation mechanism.

  3. Measures of maximum magnetic field in 3 GHz radio frequency superconducting cavities

    Theoretical models have shown that the maximum magnetic field in radio frequency superconducting cavities is the superheating field Hsh. For niobium, Hsh is 25 - 30% higher than the thermodynamical Hc field: Hsh within (240 - 274) mT. However, the maximum magnetic field observed so far is in the range Hc,max = 152 mT for the best 1.3 GHz Nb cavities. This field is lower than the critical field Hc1 above which the superconductor breaks up into divided normal and superconducting zones (Hc1≤Hc). Thermal instabilities are responsible for this low value. In order to reach Hsh before thermal breakdown, high power short pulses are used. The cavity needs then to be strongly over-coupled. The dedicated test bed has been built from the collaboration between Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Genoa, and the Service d'Etudes et Realisation d'Accelerateurs (SERA) of Laboratoire de l'Accelerateur Lineaire (LAL). The maximum magnetic field, Hrf,max, measurements on INFN cavities give lower results than the theoretical speculations and are in agreement with previous results. The superheating magnetic fields is linked to the magnetic penetration depth. This superconducting characteristic length can be used to determine the quality of niobium through the ratio between the resistivity measured at 300 K and 4.2 K in the normal conducting state (RRR). Results have been compared to previous ones and agree pretty well. They show that the RRR measured on cavities is superficial and lower than the RRR measured on samples which concerns the volume. (author)

  4. A 3 to 5 GHz low-phase-noise fractional-N frequency synthesizer with adaptive frequency calibration for GSM/PCS/DCS/WCDMA transceivers

    A low-phase-noise Σ—Δ fractional-N frequency synthesizer for GSM/PCS/DCS/WCDMA transceivers is presented. The voltage controlled oscillator is designed with a modified digital controlled capacitor array to extend the tuning range and minimize phase noise. A high-resolution adaptive frequency calibration technique is introduced to automatically choose frequency bands and increase phase-noise immunity. A prototype is implemented in 0.13 μm CMOS technology. The experimental results show that the designed 1.2 V wideband frequency synthesizer is locked from 3.05 to 5.17 GHz within 30 μs, which covers all five required frequency bands. The measured in-band phase noise are −89, −95.5 and −101 dBc/Hz for 3.8 GHz, 2 GHz and 948 MHz carriers, respectively, and accordingly the out-of-band phase noise are −121, −123 and −132 dBc/Hz at 1 MHz offset, which meet the phase-noise-mask requirements of the above-mentioned standards. (semiconductor integrated circuits)

  5. Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

    We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristics.

  6. Calibrated complex impedance of CHO cells and E. coli bacteria at GHz frequencies using scanning microwave microscopy

    Tuca, Silviu-Sorin; Badino, Giorgio; Gramse, Georg; Brinciotti, Enrico; Kasper, Manuel; Oh, Yoo Jin; Zhu, Rong; Rankl, Christian; Hinterdorfer, Peter; Kienberger, Ferry

    2016-04-01

    The application of scanning microwave microscopy (SMM) to extract calibrated electrical properties of cells and bacteria in air is presented. From the S 11 images, after calibration, complex impedance and admittance images of Chinese hamster ovary cells and E. coli bacteria deposited on a silicon substrate have been obtained. The broadband capabilities of SMM have been used to characterize the bio-samples between 2 GHz and 20 GHz. The resulting calibrated cell and bacteria admittance at 19 GHz were Y cell = 185 μS + j285 μS and Y bacteria = 3 μS + j20 μS, respectively. A combined circuitry-3D finite element method EMPro model has been developed and used to investigate the frequency response of the complex impedance and admittance of the SMM setup. Based on a proposed parallel resistance-capacitance model, the equivalent conductance and parallel capacitance of the cells and bacteria were obtained from the SMM images. The influence of humidity and frequency on the cell conductance was experimentally studied. To compare the cell conductance with bulk water properties, we measured the imaginary part of the bulk water loss with a dielectric probe kit in the same frequency range resulting in a high level of agreement.

  7. Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

    Davis, R. J.; Wilkinson, A.; Davies, R. D.; Winder, W. F.; Roddis, N.; Blackhurst, E. J.; Lawson, D.; Lowe, S. R.; Baines, C.; Butlin, M.; Galtress, A.; Shepherd, D.; Aja, B.; Artal, E.; Bersanelli, M.; Butler, R. C.; Castelli, C.; Cuttaia, F.; D'Arcangelo, O.; Gaier, T.; Hoyland, R.; Kettle, D.; Leonardi, R.; Mandolesi, N.; Mennella, A.; Meinhold, P.; Pospieszalski, M.; Stringhetti, L.; Tomasi, M.; Valenziano, L.; Zonca, A.

    2009-12-01

    We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristcs.

  8. Microwave soft x-ray microscopy for nanoscale magnetization dynamics in the 5-10 GHz frequency range

    Bonetti, Stefano; Kukreja, Roopali; Chen, Zhao; Spoddig, Detlef; Ollefs, Katharina; Schöppner, Christian; Meckenstock, Ralf; Ney, Andreas; Pinto, Jude; Houanche, Richard; Frisch, Josef; Stöhr, Joachim; Dürr, Hermann A.; Ohldag, Hendrik

    2015-09-01

    We present a scanning transmission x-ray microscopy setup combined with a novel microwave synchronization scheme for studying high frequency magnetization dynamics at synchrotron light sources. The sensitivity necessary to detect small changes in the magnetization on short time scales and nanometer spatial dimensions is achieved by combining the excitation mechanism with single photon counting electronics that is locked to the synchrotron operation frequency. Our instrument is capable of creating direct images of dynamical phenomena in the 5-10 GHz range, with high spatial resolution. When used together with circularly polarized x-rays, the above capabilities can be combined to study magnetic phenomena at microwave frequencies, such as ferromagnetic resonance (FMR) and spin waves. We demonstrate the capabilities of our technique by presenting phase resolved images of a ˜6 GHz nanoscale spin wave generated by a spin torque oscillator, as well as the uniform ferromagnetic precession with ˜0.1° amplitude at ˜9 GHz in a micrometer-sized cobalt strip.

  9. Microwave soft x-ray microscopy for nanoscale magnetization dynamics in the 5–10 GHz frequency range

    Bonetti, Stefano, E-mail: bonetti@slac.stanford.edu; Chen, Zhao [Department of Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Kukreja, Roopali [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Spoddig, Detlef; Schöppner, Christian; Meckenstock, Ralf [Institut für Experimentalphysik, Universität Duisburg-Essen, Duisburg (Germany); Ollefs, Katharina [Institut für Experimentalphysik, Universität Duisburg-Essen, Duisburg (Germany); European Synchrotron Radiation Facility, 38043 Grenoble Cedex (France); Ney, Andreas [Institut für Experimentalphysik, Universität Duisburg-Essen, Duisburg (Germany); Solid State Physics Division, Johannes Kepler University, 4040 Linz (Austria); Pinto, Jude; Houanche, Richard; Frisch, Josef [Linear Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stöhr, Joachim; Dürr, Hermann A. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Ohldag, Hendrik [Stanford Synchrotron Radiation Laboratory, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2015-09-15

    We present a scanning transmission x-ray microscopy setup combined with a novel microwave synchronization scheme for studying high frequency magnetization dynamics at synchrotron light sources. The sensitivity necessary to detect small changes in the magnetization on short time scales and nanometer spatial dimensions is achieved by combining the excitation mechanism with single photon counting electronics that is locked to the synchrotron operation frequency. Our instrument is capable of creating direct images of dynamical phenomena in the 5-10 GHz range, with high spatial resolution. When used together with circularly polarized x-rays, the above capabilities can be combined to study magnetic phenomena at microwave frequencies, such as ferromagnetic resonance (FMR) and spin waves. We demonstrate the capabilities of our technique by presenting phase resolved images of a ∼6 GHz nanoscale spin wave generated by a spin torque oscillator, as well as the uniform ferromagnetic precession with ∼0.1° amplitude at ∼9 GHz in a micrometer-sized cobalt strip.

  10. The highest-frequency detection of a radio relic: 16-GHz AMI observations of the `Sausage' cluster

    Stroe, Andra; Harwood, Jeremy J; van Weeren, Reinout; Röttgering, Huub J A; Saunders, Richard D E; Sobral, David; Perrott, Yvette C; Schammel, Michel P

    2014-01-01

    We observed the cluster CIZA J2242.8+5301 with the Arcminute Microkelvin Imager at $16$ GHz and present the first high radio-frequency detection of diffuse, non-thermal cluster emission. This cluster hosts a variety of bright, extended, steep-spectrum synchrotron-emitting radio sources, associated with the intra-cluster medium, called radio relics. Most notably, the northern, Mpc-wide, narrow relic provides strong evidence for diffusive shock acceleration in clusters. We detect a puzzling, flat-spectrum, diffuse extension of the southern relic, which is not visible in the lower radio-frequency maps. The northern radio relic is unequivocally detected and measures an integrated flux of $1.2\\pm0.3$ mJy. While the low-frequency ($<2$ GHz) spectrum of the northern relic is well represented by a power-law, it clearly steepens towards $16$ GHz. This result is inconsistent with diffusive shock acceleration predictions of ageing plasma behind a uniform shock front. The steepening could be caused by an inhomogeneous...

  11. Radio Frequency Transistors Using Aligned Semiconducting Carbon Nanotubes with Current-Gain Cutoff Frequency and Maximum Oscillation Frequency Simultaneously Greater than 70 GHz.

    Cao, Yu; Brady, Gerald J; Gui, Hui; Rutherglen, Chris; Arnold, Michael S; Zhou, Chongwu

    2016-07-26

    In this paper, we report record radio frequency (RF) performance of carbon nanotube transistors based on combined use of a self-aligned T-shape gate structure, and well-aligned, high-semiconducting-purity, high-density polyfluorene-sorted semiconducting carbon nanotubes, which were deposited using dose-controlled, floating evaporative self-assembly method. These transistors show outstanding direct current (DC) performance with on-current density of 350 μA/μm, transconductance as high as 310 μS/μm, and superior current saturation with normalized output resistance greater than 100 kΩ·μm. These transistors create a record as carbon nanotube RF transistors that demonstrate both the current-gain cutoff frequency (ft) and the maximum oscillation frequency (fmax) greater than 70 GHz. Furthermore, these transistors exhibit good linearity performance with 1 dB gain compression point (P1dB) of 14 dBm and input third-order intercept point (IIP3) of 22 dBm. Our study advances state-of-the-art of carbon nanotube RF electronics, which have the potential to be made flexible and may find broad applications for signal amplification, wireless communication, and wearable/flexible electronics. PMID:27327074

  12. A HBAR-oscillator-based 4.596~GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    Daugey, Thomas; Martin, Gilles; Boudot, Rodolphe

    2015-01-01

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596~GHz frequency source. A 2.298~GHz signal, generated by an oscillator constructed around a thermally-controlled two-port AlN-sapphire HBAR resonator with a Q-factor of 24000 at 68$^{\\circ}$C, is frequency multiplied by 2 to 4.596~GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency (TCF) of the HBAR is measured to be $-23$~ppm/$^{\\circ}$C at 2.298~GHz. The measured phase noise of the 4.596~GHz source is $-105$~dBrad$^2$/Hz at 1~kHz offset and $-150$~dBrad$^2$/Hz at 100~kHz offset. The 4.596~GHz output signal is used as a local oscillator (LO) in a laboratory-prototype Cs microcell-based coherent population trapping (CPT) atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter (VCPS) implemented in the 2.298~GHz HBAR-oscillator loop, preventing the need for a high-power-consuming...

  13. Surfatron plasma source working at frequency 2.45 GHz for technological applications

    Plasma as an active medium is widely exploited in technological applications processes. To the most important plasma application belongs plasma-aided surface processing of solid-state samples. Due to unique reactivity and chemical interaction with materials, plasma is capable to treat the surface i.e. to be used for material deposition, surface cleaning or surface activation, sterilisation etc. We attempted to develop microwave plasma source, based on surfatron that is potentially applicable for technological purposes. Plasma is generated by commercial (Sairem) surfatron working at frequency 2.45 GHz. The surfatron is fed by microwave power in the range from several watts up to 300 watts. A quartz tube is inserted into surfatron cavity. The outlet of the tube is situated in a cylindrical vacuum vessel pumped out by rotary vacuum pump. The microwave power interacts with the working gas (we used Ar or He as carrier gases with reactive admixtures of O2 or N2) which flows through quartz tube, and ionizes the gas/mixture. The azimuthally symmetric surface wave then sustains created plasma also further downstream of the quartz tube end to the reactor vessel volume. Substrate table movable in three dimensions by stepping motors and controlled via computer is located inside the vessel. This equipment allows uniform surface treatment of the samples. The generator can be operated in cw as well as in computer-controlled impulse regime. The impulse regime of plasma source is one of the ways how to prevent treated materials (especially thermal sensitive materials, e.g. plastics) against thermal damage. Plasma exiting the tube was studied with Langmuir probes and optical spectroscopy. These diagnostics were done at different experimental conditions. Single probe method was used for determination of basic plasma parameters (plasma potential Vpl, mean electron energy Em, electron density ne, EEDF) at low pressures. Double probe method was used at higher vessel pressures when ion

  14. The widest frequency radio relic spectra: observations from 150 MHz to 30 GHz

    Stroe, Andra; Shimwell, Timothy; Rumsey, Clare; Weeren, Reinout; Kierdorf, Maja; Donnert, Julius; Jones, Thomas W.; Röttgering, Huub J. A.; Hoeft, Matthias; Rodriguez-Gonzalvez, Carmen; Harwood, Jeremy J.; Saunders, Richard D. E.

    2015-01-01

    Radio relics are patches of diffuse synchrotron radio emission that trace shock waves. Relics are thought to form when intra-cluster medium electrons are accelerated by cluster merger induced shock waves through the diffusive shock acceleration mechanism. In this paper, we present observations spanning 150 MHz to 30 GHz of the `Sausage' and `Toothbrush' relics from the Giant Metrewave and Westerbork telescopes, the Karl G. Jansky Very Large Array, the Effelsberg telescope, the Arcminute Micro...

  15. Complex permeability and permittivity variation of carbonyl iron rubber in the frequency range of 2 to 18 GHz

    Adriana Medeiros Gama

    2010-04-01

    Full Text Available The complex dielectric permittivity (e and magnetic permeability (m of Radar Absorbing Materials (RAM based on metallic magnetic particles (carbonyl iron particles embedded in a dielectric matrix (silicon rubber have been studied in the frequency range of 2 to 18 GHz. The relative permeability and permittivity of carbonyl iron-silicon composites for various mass fractions are measured by the transmission/reflection method using a vector network analyzer. The concentration dependence of permittivity and permeability on the frequency is analyzed. In a general way, the results show that e´ parameter shows a more significant variation among the evaluated parameters (e”, m”, m’. The comparison of dielectric and magnetic loss tangents (e”/e” and m”/m’, respectively shows more clearly the variation of both parameters (e and m according to the frequency. It is also observed that higher carbonyl iron content fractions favor both dielectric and magnetic loss tangents.

  16. A 12.5 GHz-spaced optical frequency comb spanning >400 nm for near-infrared astronomical spectrograph calibration

    A 12.5 GHz-spaced optical frequency comb locked to a global positioning system disciplined oscillator for near-infrared (IR) spectrograph calibration is presented. The comb is generated via filtering a 250 MHz-spaced comb. Subsequent nonlinear broadening of the 12.5 GHz comb extends the wavelength range to cover 1380-1820 nm, providing complete coverage over the H-band transmission window of earth's atmosphere. Finite suppression of spurious sidemodes, optical linewidth, and instability of the comb has been examined to estimate potential wavelength biases in spectrograph calibration. Sidemode suppression varies between 20 and 45 dB, and the optical linewidth is ∼350 kHz at 1550 nm. The comb frequency uncertainty is bounded by ±30 kHz (corresponding to a radial velocity of ±5 cm/s), limited by the global positioning system disciplined oscillator reference. These results indicate that this comb can readily support radial velocity measurements below 1 m/s in the near IR.

  17. Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

    Davis, R J; Davies, R D; Winder, W F; Roddis, N; Blackhurst, E J; Lawson, D; Lowe, S R; Baines, C; Butlin, M; Galtress, A; Shepherd, D; Aja, B; Artal, E; Bersanelli, M; Butler, R C; Castelli, C; Cuttaia, F; D'Arcangelo, O; Gaier, T; Hoyland, R; Kettle, D; Leonardi, R; Mandolesi, N; Mennella, A; Meinhold, P; Pospieszalski, M; Stringhetti, L; Tomasi, M; Valenziano, L; Zonca, A; 10.1088/1748-0221/4/12/T12002

    2009-01-01

    We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is stil...

  18. A 5 GHz CMOS frequency synthesizer with novel phase-switching prescaler and high-Q LC-VCO

    A phase-locked loop (PLL) frequency synthesizer with a novel phase-switching prescaler and a high-Q LC voltage controlled oscillator (VCO) is presented. The phase-switching prescaler with a novel modulus control mechanism is much more robust on process variations. The Q factor of the inductor, I-MOS capacitors and varactors in the VCO are optimized. The proposed frequency synthesizer was fabricated by SMIC 0.13 μm 1P8M MMRF CMOS technology with a chip area of 1150 x 2500 μm2. When locking at 5 GHz, the current consumption is 15 mA from a supply voltage of 1.2 V and the measured phase noise at a 1 MHz offset is -122.45 dBc/Hz.

  19. The contribution of microbunching instability to solar flare emission in the GHz to THz range of frequencies

    Klopf, J Michael; Raulin, Jean-Pierre; Szpigel, Sérgio

    2014-01-01

    Recent solar flare observations in the sub-THz range have provided evidence of a new spectral component with fluxes increasing for larger frequencies, separated from the well-known microwave emission that maximizes in the GHz range. Suggested interpretations explain the THz spectral component, but do not account for the simultaneous microwave component. We present a mechanism for producing the observed double-spectra. Based on coherent enhancement of synchrotron emission at long wavelengths in laboratory accelerators, we consider how similar processes may occur within a solar flare. The instability known as microbunching arises from perturbations that produce electron beam density modulations, giving rise to broadband coherent synchrotron emission at wavelengths comparable to the characteristic size of the microbunch structure. The spectral intensity of this coherent synchrotron radiation (CSR) can far exceed that of the incoherent synchrotron radiation (ISR), which peaks at higher frequency, thus producing a...

  20. Continuous-Wave Operation of a Frequency-Tunable 460-GHz Second-Harmonic Gyrotron for Enhanced Nuclear Magnetic Resonance.

    Torrezan, Antonio C; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J; Barnes, Alexander B; Griffin, Robert G

    2010-06-01

    The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE(11,2) and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE(11,2,q). The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:21243088

  1. Remote sensing of soil moisture content over bare field at 1.4 GHz frequency

    Wang, J. R.; Choudhury, B. J.

    1981-01-01

    An algorithm for estimating moisture content of a bare soil from the observed brightness temperature at 1.4 GHz is discussed and applied to a limited data base. The method is based on a radiative transfer model calculation, which has been successfully used in the past to account for many observational results, with some modifications to take into account the effect of surface roughness. Besides the measured brightness temperatures, the three additional inputs required by the method are the effective soil thermodynamic temperature, the precise relation between moisture content and the smooth field brightness temperatures and a pair of parameters related to surface roughness. The procedures of estimating surface roughness parameters and of obtaining moisture content from observed brightness temperature are discussed. The algorithm is applied to observations from truck mounted and airborne radiometers. The estimated moisture contents compare favorably with the observations in the top 2 cm layer.

  2. A stabilized 18 GHz chip-scale optical frequency comb at 2.8x10-16 relative inaccuracy

    Huang, S -W; Yu, M; McGuyer, B H; Kwong, D -L; Zelevinsky, T; Wong, C W

    2015-01-01

    Optical frequency combs, coherent light sources that connect optical frequencies with microwave oscillations, have become the enabling tool for precision spectroscopy, optical clockwork and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but four-wave-mixing in high-Q resonators have emerged as alternative platforms. Here we report the generation and full stabilization of CMOS-compatible optical frequency combs. The spiral microcomb's two degrees-of-freedom, one of the comb line and the native 18 GHz comb spacing, are first simultaneously phase-locked to known optical and microwave references. Second, with pump power control, active comb spacing stabilization improves the long-term stability by six orders-of-magnitude, reaching an instrument-limited 3.6 mHz/sqrt(t) residual instability. Third, referencing thirty-three of the nitride frequency comb lines against a fiber comb, we demonstrate the comb tooth-to-tooth frequency relative inaccu...

  3. Power measurement for frequencies up to approx.1 GHz using a sampling oscilloscope and a low-frequency multiplier

    Accurate measurement of electrical power above approx.1 MHz is accomplished by reconstruction of the voltage and current waveforms at a lower frequency using a sampling oscilloscope. The low-frequency waveforms are then multiplied in a 4-quadrant tranconductance-type multiplier module

  4. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad2/Hz at 1 kHz offset and −150 dB rad2/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10−9 at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10−11 τ−1/2 up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance

  5. Electromagnetic interference shielding effectiveness of composite carbon nanotube macro-film at a high frequency range of 40 GHz to 60 GHz

    Zi Ping Wu; Ming Cheng; Wen Jing Ma; Jing Wei Hu; Yan Hong Yin; Ying Yan Hu; Ye Sheng Li; Jian Gao Yang; Qian Feng Xu

    2015-01-01

    The electromagnetic interference (EMI) shielding effectiveness (SE) of carbon nanotube (CNT) macro-film that is adhered to common cloth to maintain the light weight, silk-like quality, and smooth surface of the material for EMI shielding is investigated. The results show that a high and stable EMI SE of 48 dB to 57 dB at 40 GHz to 60 GHz was obtained by the macro-film with a thickness of only ∼4 μm. The composite CNT macro-film is easily manipulated, and its EMI property is significantly diff...

  6. Sensing glucose concentrations at GHz frequencies with a fully embedded Biomicro-electromechanical system (BioMEMS)

    Birkholz, M.; Ehwald, K.-E.; Basmer, T.; Kulse, P.; Reich, C.; Drews, J.; Genschow, D.; Haak, U.; Marschmeyer, S.; Matthus, E.; Schulz, K.; Wolansky, D.; Winkler, W.; Guschauski, T.; Ehwald, R.

    2013-06-01

    The progressive scaling in semiconductor technology allows for advanced miniaturization of intelligent systems like implantable biosensors for low-molecular weight analytes. A most relevant application would be the monitoring of glucose in diabetic patients, since no commercial solution is available yet for the continuous and drift-free monitoring of blood sugar levels. We report on a biosensor chip that operates via the binding competition of glucose and dextran to concanavalin A. The sensor is prepared as a fully embedded micro-electromechanical system and operates at GHz frequencies. Glucose concentrations derive from the assay viscosity as determined by the deflection of a 50 nm TiN actuator beam excited by quasi-electrostatic attraction. The GHz detection scheme does not rely on the resonant oscillation of the actuator and safely operates in fluidic environments. This property favorably combines with additional characteristics—(i) measurement times of less than a second, (ii) usage of biocompatible TiN for bio-milieu exposed parts, and (iii) small volume of less than 1 mm3—to qualify the sensor chip as key component in a continuous glucose monitor for the interstitial tissue.

  7. Design and simulation of circularly polarized pentagonal-shaped microstrip patch antenna at RFID frequency 2.4 GHz

    Bondili Kohitha Bai

    2012-01-01

    Full Text Available In wireless communication system antennas play an inherent role. In terms of geometrical shapes and implementations microstrip patch antennas are versatile in nature. Characteristics like low gain and smaller bandwidth make single microstrip more popular. Printed type of antenna which consists of a radiating patch on one side of a dielectric substrate and ground plane on the other side is a microstrip patch antenna. The intension of exploiting design is to implement a circularly polarized pentagonal-shaped microstrip patch antenna with a dielectric constant of 2.33, for a dielectric substrate. The antenna is designed and simulated using IE3D electromagnetic simulator. Circularly polarized pentagonal-shaped microstrip patch antenna has good CP axial ratio bandwidth and minimum reflection coefficient. The aimed antenna designed for WLAN applications at RFID frequency of 2.4 GHz in ISM band. The simulation outcomes shows that the designed CP pentagonal shaped microstrip patch antenna gives axial ratio of 0.6023 at 2.38 GHz and CP axial ratio bandwidth of 36MHz with 1.5%.

  8. An open-ended waveguide system for SAR system validation or probe calibration for frequencies above 3 GHz

    Compliance with safety guidelines prescribed in terms of maximum electromagnetic power absorption (specific absorption rate or SAR) for any 1- or 10-g of tissue is required for all newly introduced personal wireless devices such as wireless PCs. The prescribed SAR measuring system is a planar phantom with a relatively thin base of thickness 2.0 mm filled with a lossy fluid to simulate dielectric properties of the tissues. A well-characterized, broadband irradiator is required for SAR system validation or submerged E-field probe calibration for the Wi-Fi frequencies in the 5-6 GHz band. We describe an open-ended waveguide system that may be used for this purpose. Using a fourth-order polynomial least-squares fit to the experimental data gives SAR variations close to the bottom surface of the phantom that are in excellent agreement with those obtained using the finite-difference time-domain (FDTD) numerical method. The experimentally determined peak 1- and 10-g SARs are within 1 to 2% of those obtained using the FDTD both at 5.25 and 5.8 GHz

  9. The faint source population at 15.7 GHz - III. A high-frequency study of HERGs and LERGs

    Whittam, Imogen H; Green, David A; Jarvis, Matt J

    2016-01-01

    A complete sample of 96 faint ($S > 0.5$ mJy) radio galaxies is selected from the Tenth Cambridge (10C) survey at 15.7~GHz. Optical spectra are used to classify 17 of the sources as high-excitation or low-excitation radio galaxies (HERGs and LERGs respectively), for the remaining sources three other methods are used; these are optical compactness, X-ray observations and mid-infrared colour--colour diagrams. 32 sources are HERGs and 35 are LERGs while the remaining 29 sources could not be classified. We find that the 10C HERGs tend to have higher 15.7-GHz flux densities, flatter spectra, smaller linear sizes and be found at higher redshifts than the LERGs. This suggests that the 10C HERGs are more core dominated than the LERGs. Lower-frequency radio images, linear sizes and spectral indices are used to classify the sources according to their radio morphology; 18 are Fanaroff and Riley type I or II sources, a further 13 show some extended emission, and the remaining 65 sources are compact and are referred to as...

  10. Dual-frequency comb generation with differing GHz repetition rates by parallel Fabry–Perot cavity filtering of a single broadband frequency comb source

    Mildner, Jutta; Meiners-Hagen, Karl; Pollinger, Florian

    2016-07-01

    We present a dual-comb-generator based on a coupled Fabry–Perot filtering cavity doublet and a single seed laser source. By filtering a commercial erbium-doped fiber-based optical frequency comb with CEO-stabilisation and 250 MHz repetition rate, two broadband coherent combs of different repetition rates in the GHz range are generated. The filtering doublet consists of two Fabry–Perot cavities with a tunable spacing and Pound–Drever–Hall stabilisation scheme. As a prerequisite for the development of such a filtering unit, we present a method to determine the actual free spectral range and transmission bandwidth of a Fabry–Perot cavity in situ. The transmitted beat signal of two diode lasers is measured as a function of their tunable frequency difference. Finally, the filtering performance and resulting beat signals of the heterodyned combs are discussed as well as the optimisation measures of the whole system.

  11. Precision waveguide system for measurement of complex permittivity of liquids at frequencies from 60 to 90 GHz.

    Hunger, J; Cerjak, I; Schoenmaker, H; Bonn, M; Bakker, H J

    2011-10-01

    We describe a variable path length waveguide setup developed to accurately measure the complex dielectric permittivity of liquids. This is achieved by measuring the complex scattering parameter of the liquid in a waveguide section with a vector network analyzer in combination with an E-band frequency converter. The automated measurement procedure allows fast acquisition at closely spaced intervals over the entire measurement bandwidth: 60-90 GHz. The presented technique is an absolute method and as such is not prone to calibration errors. The technique is suited to investigate low-loss as well as high-loss liquids in contrast to similar setups described previously. We present measurements for a high-loss liquid (water), an intermediate-loss sample (ethanol), and for nearly loss-less n-octane. Due to the available phase information, the present data have an improved accuracy in comparison with literature data. PMID:22047313

  12. Precision waveguide system for measurement of complex permittivity of liquids at frequencies from 60 to 90Â GHz

    Hunger, J.; Cerjak, I.; Schoenmaker, H.; Bonn, M.; Bakker, H. J.

    2011-10-01

    We describe a variable path length waveguide setup developed to accurately measure the complex dielectric permittivity of liquids. This is achieved by measuring the complex scattering parameter of the liquid in a waveguide section with a vector network analyzer in combination with an E-band frequency converter. The automated measurement procedure allows fast acquisition at closely spaced intervals over the entire measurement bandwidth: 60-90 GHz. The presented technique is an absolute method and as such is not prone to calibration errors. The technique is suited to investigate low-loss as well as high-loss liquids in contrast to similar setups described previously. We present measurements for a high-loss liquid (water), an intermediate-loss sample (ethanol), and for nearly loss-less n-octane. Due to the available phase information, the present data have an improved accuracy in comparison with literature data.

  13. Digital coherent detection of multi-gigabit 40 GHz carrier frequency radio-over-fiber signals using photonic downconversion

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    Detection of high speed radio signals is a challenge for next generation radio-over-fiber links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, it is possible to detect signals exceeding the electrical bandwidth of the receiver, by...... performing the mixing of the radio signal with a free-running local oscillator in the optical domain. In this paper we present the experimental emonstration of high bitrate 16-QAM signal detection, up to 4 Gb/s, at 40 GHz carrier frequency, using low bandwidth electronics.......Detection of high speed radio signals is a challenge for next generation radio-over-fiber links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, it is possible to detect signals exceeding the electrical bandwidth of the receiver, by...

  14. Remote sensing of soil moisture content over bare fields at 1.4 GHz frequency

    Wang, J. R.; Choudhury, B. J.

    1980-01-01

    A simple method of estimating moisture content (W) of a bare soil from the observed brightness temperature (T sub B) at 1.4 GHz is discussed. The method is based on a radiative transfer model calculation, which has been successfully used in the past to account for many observational results, with some modifications to take into account the effect of surface roughness. Besides the measured T sub B's, the three additional inputs required by the method are the effective soil thermodynamic temperature, the precise relation between W and the smooth field brightness temperature T sub B and a parameter specifying the surface roughness characteristics. The soil effective temperature can be readily measured and the procedures of estimating surface roughness parameter and obtaining the relation between W and smooth field brightness temperature are discussed in detail. Dual polarized radiometric measurements at an off-nadir incident angle are sufficient to estimate both surface roughness parameter and W, provided that the relation between W and smooth field brightness temperature at the same angle is known. The method of W estimate is demonstrated with two sets of experimental data, one from a controlled field experiment by a mobile tower and the other, from aircraft overflight. The results from both data sets are encouraging when the estimated W's are compared with the acquired ground truth of W's in the top 2 cm layer. An offset between the estimated and the measured W's exists in the results of the analyses, but that can be accounted for by the presently poor knowledge of the relationship between W and smooth field brightness temperature for various types of soils. An approach to quantify this relationship for different soils and thus improve the method of W estimate is suggested.

  15. Laser frequency locking with 46 GHz offset using an electro-optic modulator for magneto-optical trapping of francium atoms

    Harada, K; Ezure, S; Kato, K; Hayamizu, T; Kawamura, H; Inoue, T; Arikawa, H; Ishikawa, T; Aoki, T; Uchiyama, A; Sakamoto, K; Ito, S; Itoh, M; Ando, S; Hatakeyama, A; Hatanaka, K; Imai, K; Murakami, T; Nataraj, H S; Shimizu, Y; Sato, T; Wakasa, T; Yoshida, H P; Sakemi, Y

    2016-01-01

    We demonstrated a frequency offset locking between two laser sources using a waveguide-type electro-optic modulator (EOM) with 10th-order sidebands for magneto-optical trapping of Fr atoms. The frequency locking error signal was successfully obtained by performing delayed self-homodyne detection of the beat signal between the repumping frequency and the 10th-order sideband component of the trapping light. Sweeping the trapping-light and repumping-light frequencies with keeping its frequency difference of 46 GHz was confirmed over 1 GHz by monitoring the Doppler absorption profile of I2. This technique enables us to search for a resonance frequency of magneto-optical trapping of Fr.

  16. Second-order fractional Talbot effect induced frequency-doubling optical pulse injection for 40 GHz rational-harmonic mode-locking of an SOA fiber laser

    A second-order fractional Talbot effect induced frequency-doubling of a 10 GHz optical pulse-train is demonstrated to backward injection mode-lock a semiconductor optical amplifier fiber laser (SOAFL) for 40 GHz rational-harmonic mode-locking (RHML). That is, a real all-optical gain-modulation of the SOAFL can be created by injecting such a time-multiplexed but pseudo-frequency-doubled pulse-train into the cavity. The time-multiplexing pulse-train can thus be transformed into a frequency-multiplied pulse-train via cross-gain modulation (XGM). The optical pulse-train at 10 GHz is generated by nonlinearly driving an electro-absorption modulator (EAM), which experiences the second-order fractional Talbot effect after propagating through a 4 km long dispersion compensation fiber (DCF). The DCF not only plays the role of frequency-doubler but also compensates the frequency chirp of the 10 GHz optical pulse-train. The pulsewidth broadening from 22 to 60 ps for initiating the time-domain Talbot effect is simulated by the nonlinear Schrödinger equation. With careful detuning of the RF modulation power of the EAM at 5 dBm, the generated 20 GHz optical pulse-train exhibits a positive frequency chirp with minimum peak-to-peak value of 2 GHz, and the peak-amplitude fluctuation between adjacent pulses is below 1.4%. In comparison with the SOAFL pulse-train repeated at 40 GHz generated by the fourth-order purely RHML process, the optimized second-order fractional Talbot effect in combination with the second-order RHML mechanism significantly enhances the modulation-depth of RHML, thus improving the on/off extinction ratio of the 40 GHz SOAFL pulse-train from 1.8 to 5.6 dB. Such a new scheme also provides a more stable 40 GHz RHML pulse-train from the SOAFL with its timing jitter reducing from 0.51 to 0.23 ps. (paper)

  17. Radio Frequency Mapping using an Autonomous Robot: Application to the 2.4 GHz Band

    Lebreton, J. M.; Murad, N. M.; Lorion, R.

    2016-03-01

    Radio signal strength measurement systems are essential to build a Radio Frequency (RF) mapping in indoor and outdoor environments for different application scenarios. This paper presents an autonomous robot making the construction of a radio signal mapping, by collecting and forwarding different useful information related to all access point devices and inherent to the robot towards the base station. A real case scenario is considered by measuring the RF field from our department network. The RF signal mapping consistency is shown by fitting the measurements with the radio signal strength model in two-dimensional area, and a path-loss exponent of 2.3 is estimated for the open corridor environment.

  18. Design of a LNA in the frequency band 1.8-2.2GHz in 0.13μm CMOS Technology

    E. Di Gioia

    2005-01-01

    Full Text Available The subject of this work is a low noise amplifier (LNA, operating in the frequency range 1.8-2.1GHz. The CMOS 0.13μm technology is used in respect to the low cost of the final device. Among the specifications, a variable gain and an adjustable working frequency are required. In particular, four different working modes are provided: 1.8, 1.9 and 2.1GHz high gain and 2.1GHz low gain. The amplifier is designed to be used as first stage of a receiver for mobile telephony. For this reason low power consumption is taken into consideration (low supply voltage and low drain currents. A simple digital circuit, integrated on-chip, is used to select the operating mode of the LNA by means of two input pins. A Noise figure of 1dB is obtained with a supply voltage of 0.8V.

  19. Effects of low intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies and antibiotics on energy-dependent proton and potassium ion transport by E. coli.

    Torgomyan, H

    2012-12-01

    The effects of low intensity (flux capacity 0.06 mW/cm2) coherent electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies and their combined effects with antibiotics--ceftriaxone or kanamycin (0.4 or 15 microM, correspondingly) on E. coli K12 growth and survival have been reported previously. To further study the effects of EMI and antibiotics and mechanisms, decrease in overall energy (glucose)-dependent H+ and K+ fluxes across the cell membrane was investigated in E. coli. The depression of H+ and K+ fluxes rate was maximally achieved with the 73 GHz frequency. The EMI strengthened the effect of N,N'-dicyclohexycarbodiimide (DCCD, an inhibitor of the F0F1-ATPase). The 73 GHz EMI had more influence on H+ efflux inhibition, whereas 70.6 GHz on K+ influx. Also, EMI strengthened the depressive effects of ceftriaxone and kanamycin on the overall and DCCD-inhibited H+ and K+ fluxes. The 73 GHz EMI strengthened the effect of ceftriaxone on both ions fluxes. Kanamycin depressed H+ efflux more as compared to ceftriaxone, which was also strengthened with EMI. The results of E. coli H+ and K+ transport systems activities depression by irradiation and the irradiation effect on DCCD and antibiotics action indicated the EMI and antibiotics causing primary changes in the bacterial membrane. PMID:23350277

  20. Numerical investigation of In{sub 0.23}Ga{sub 0.77}As-based planar Gunn diodes with fundamental frequency up to 116 GHz

    Li, B.; Wen, C. [Southwest University of Science and Technology, School of Science, Mianyang (China); Liu, H.X. [Xidian University, School of Microelectronics, Xi' an (China)

    2015-09-15

    The current capability and frequency of In{sub 0.23}Ga{sub 0.77}As-based planar Gunn diode have been studied using numerical simulation. Our simulated results are well in agreement with the experimental observation with fundamental frequency operating up to 116 GHz. Through the Fast Fourier transform algorithm, it has been revealed that oscillating frequency tunes downward slightly with increased applied voltage above threshold voltage, and a second-harmonic frequency is observed at 233 GHz for 1.45-μm channel length. This structure provides feasibility of generating a tunable millimeter wave or terahertz wave source and has an overwhelming advantage over equivalent traditional vertical structure because of increased facilitated integration and flexibility. (orig.)

  1. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    Biri, S., E-mail: biri@atomki.hu [National Institute of Radiological Science (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Kitagawa, A.; Muramatsu, M.; Drentje, A. G. [National Institute of Radiological Science (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Rácz, R. [Institute for Nuclear Research (ATOMKI), H-4026 Debrecen, Bem tér 18/c (Hungary); Yano, K.; Kato, Y. [Graduated School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Sasaki, N.; Takasugi, W. [Accelerator Engineering Corporation (AEC), Inage, Chiba 263-0043 (Japan)

    2014-02-15

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1–18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1–18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

  2. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences.

    Biri, S; Kitagawa, A; Muramatsu, M; Drentje, A G; Rácz, R; Yano, K; Kato, Y; Sasaki, N; Takasugi, W

    2014-02-01

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode. PMID:24593510

  3. Impedance Modeling for a Unit Cell of the Square Loop Frequency Selective Surface at 2.4 GHz

    M.Z.A. Abd. Aziz

    2013-10-01

    Full Text Available Equivalent Circuit (EC method gives a simple alternative method in Frequency Selective Surface (FSS analyses which are useful for quickly predicting the characteristic of FSS. An impedance modeling of the Equivalent Circuit (EC for a unit cell of the square loop FSS structure is presented in this paper. The unit cell of the square loop FSS is designed and simulated using the CST Microwave Studio software at 2.4 GHz based on industrial, scientific and medical bands (ISM standard. The square loop FSS is simulated without FSS, with square FSS and square FSS with slot. The investigation has been done on the length of substrate (s, width of substrate (w, length of square FSS (a and length of square FSS with slot (b. Real (Re and Imaginary (Im component of EC or known as resistance and reactancehas been modeled based on physical parameters of the design structure of the FSS. The resistance and reactance of the impedance are depending on the geometry of the unit cell of FSS. This impedancemodelling can be used to design the advance FSS for the similar ISM band. EC gives a simple alternative method in FSS analyses which are useful for quickly predicting the performance of FSS.

  4. A More Precise Empirical Formula for Estimating Normalized Fog Attenuation in the Millimeter-Wave Frequency Range 30 ~ 100 GHz

    Mao, Xia; Liu, Yun-Long; Chen, Li-Jiang; Xue, Yu-Li

    2013-04-01

    At millimeter wavelengths, normalized fog attenuation (NFA) in units of (dB/km)/ (g/m3) is generally calculated by the Rayleigh approximation when working wavelengths are much larger than the average diameter of fog droplets. The calculations of the Rayleigh approximation are much less than those of Mie scattering theory, but still complex and heavy. To solve the above problem and facilitate the engineering applications of the Rayleigh approximation, a new empirical formula is discussed to estimate NFA in the frequency range 30 ~ 100 GHz and the fog common temperature range -8 ~ 20 °C. The simulation results of the new formula are compared with those got by other three empirical formulae: the Altshuler empirical formula, the Liebe empirical formula and the Zhao empirical formula. Maximal absolute value of the relative errors (MAVRE) and Pearson correlation coefficient (PCC) indicate the largest deviation of estimated results and the fitting performance of an empirical formula, respectively. Comparisons show that the MAVRE of the new formula is only 4.482 %, which is much smaller than those of the other three formulae. The mean value of the Pearson correlation coefficients (PCCs) of the proposed formula is 0.999943, larger than those of other methods. Additionally, relative error (RE) curves of the four empirical formulae are given at four certain temperatures -8 °C, 0 °C, 10 °C and 20 °C.

  5. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Cavity design and linear analysis of 225 GHz frequency-quadrupling gyroklystron

    Liu, Di-Wei; Yuan, Xue-Song; Yan, Yang; Liu, Sheng-Gang

    2009-07-01

    This paper considers the frequency-quadrupling three-cavity gyroklystrons with successive frequency-doubling in each cavity. The cavities of 225 GHz frequency-quadrupling gyroklystron are designed with the scattering matrices method and the possible operating mode are discussed. With the point-gap theory, the starting currents of the possible operating modes and the potential parasitic modes in the output cavity are calculated. The optimal operating mode is proposed under consideration of the mode competition and the power capacity of the cavity.

  6. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    Biri, S; Muramatsu, M; Drentje, A G; Rácz, R; Yano, K; Kato, Y; Sasaki, N; Takasugi, W

    2015-01-01

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide bandwidth (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effec...

  7. Enhanced Microwave Absorption of SiO2-Coated Fe0.65Co0.35 Flakes at a Wide Frequency Band (1-18 GHz)

    Luo, Hui; Gong, Rongzhou; Wang, Xian; Song, Kai; Chen, Yajie; Harris, Vincent G.

    2016-07-01

    Fe0.65Co0.35 (Fe-35Co) flakes were coated with SiO2 by the Stober process. The complex permittivity and permeability of both Fe-35Co and Fe-35Co/SiO2 composites were investigated over the frequency range of 1-18 GHz. Two dielectric resonance peaks were found in the Fe-35Co/SiO2 composite. Magnetic loss was verified to arise predominately from the natural resonance. Of particular importance is the natural resonance frequency increases with the SiO2 cladding. The experiments indicated that a reflection loss (RL) less than -20 dB for the Fe-35Co/SiO2 composites can be measured over the frequency range of 5.16-10.6 GHz with an absorbing thickness of 2-3.5 mm. Furthermore, an optimal RL of -60.23 dB was observed at 6.27 GHz with a thickness of 2.93 mm. The results provide a valuable path towards realizing microwave absorption over a wide frequency range.

  8. High Current Multi-finger InGaAs/InP Double Heterojunction Bipolar Transistor with the Maximum Oscillation Frequency 253 GHz

    A four-finger InGaAs/InP double heterojunction bipolar transistor is designed and fabricated successfully by using planarization technology. The emitter area of each finger is 1 × 15μm2. The breakdown voltage is more than 7 V, the maximum collector current could be more than 100 mA. The current gain cutoff frequency is as high as 155 GHz and the maximum oscillation frequency reaches 253 GHz. The heterostructure bipolar transistor can offer more than 70mW class-A maximum output power at W band and the maximum power density can be as high as 1.2W/mm. (cross-disciplinary physics and related areas of science and technology)

  9. UWB and 60-GHz RF generation and transmission over WDM-PON based on bidirectional asymmetric polarization modulation and frequency multiplication

    Liu, Weilin; Yao, Jianping

    2013-10-01

    A novel scheme to simultaneously provide UWB, 60-GHz millimeter-wave (mmW), and baseband services over a wavelength division multiplexing (WDM) passive optical network (PON) is proposed and demonstrated. In the proposed system, an OOK Gaussian pulse signal is modulated on the optical carrier and then converted to an OOK UWB impulse signal at an edge filter, a baseband signal and a 30-GHz signal are then modulated on the same optical carrier. By employing polarization multiplex technique, the UWB and baseband signal will have orthogonal polarization directions and the spectrum interference between the two signals is avoided. By suppressing the optical carrier, a frequencydoubled mmW signal at 60 GHz is generated by beating the two 1st order sidebands at a photodetector (PD). Error-free transmission of a UWB signal at 2.5 Gbps and a wired baseband signal at 2.5 and 5 Gbps over a 25-km single-mode fiber (SMF) is achieved. A frequency-doubled mmW signal at 60 GHz is also obtained.

  10. Up to 427 GHz All Optical Frequency Down-Conversion Clock Recovery Based on Quantum-Dash Fabry―Perot Mode-Locked Laser

    Costa E Silva, Marcia; Lagrost, Alexandra; Bramerie, Laurent; Gay, Mathilde; Besnard, Pascal; Joindot, Michel; Simon, Jean-Claude; Shen, Alexandre; Duan, Guang-Hua

    2011-01-01

    International audience This paper reports on all optical frequency down conversion clock recovery based on Quantum-Dash Fabry-Perot mode-locked laser diode (QD-MLLD). A first section is dedicated to the generation of a tunable repetition rate pulse source based on a first QD-MLLD. The principle is to select three lines in the QD-MLLD spectrum with a filtering technique; the lines spacing are properly chosen to generate the desired repetition rate. In this paper, a frequency of 427 GHz was ...

  11. THE EFFECT INDUCED BY MILLIMETER WAVES WITH THE FREQUENCY 53.33 GHZ ON SACCHAROMYCES CEREVISIAE CNMN-Y-18 YEAST STRAIN

    Agafia Usatîi; Elena Molodoi; Nadejda Efromova; Ludmila Fulga

    2015-01-01

    The effect of extremely high frequency electromagnetic waves on the biosynthetic activity of Saccharomyces cerevisiae CNMN-Y-18 yeast strain in dependence on the duration of irradiation was studied. The maximum amount of biomass, protein, carbohydrates, mannoproteins and catalase has been showed to accumulate when the yeast cells were irradiated with a frequency f = 53.33 GHz for 10 minutes. High degree of dependence between the content of cellular components (a correlation coefficient betwee...

  12. 11.8GHz低相噪频率源的设计%Design of 11.8 GHz low phase noise frequency synthesizer

    綦超; 姜兴

    2012-01-01

    Low phase noise frequency synthesizer plays an important role in radar system. A 11. 8 GHz low phase noise frequency synthesizer is designed for automotive anti-collision radar. Based on the study of phase locked-loop CPLL) , the possibility for the implement of low phase noise is analysed, the design of the phase frequency detector, the VCO and the loop-filter is also introduced. The test result of the 11. 8 GHz frequency synthesizer shows low phase noise is below —90 dBc/Hz at 1 kHz. The other results also reach intended targets. The 11. 8 GHz low phase noise frequency synthesizer enhances the performance of the automotive anti-collision radar.%针对汽车防撞雷达系统,设计了11.8 GHz低相噪频率源.在对锁相环技术研究的基础上,分析相位噪声达到要求指标的可行性,并介绍鉴相器电路、压控振荡器电路以及环路滤波器电路的设计.测试结果表明该输出频率为11.8 GHz的频率源获得很好的相位噪声性能,实现1 kHz处相位噪声指标优于-90 dBc/Hz,并且其他指标均达到要求.11.8 GHz低相噪频率源能提高汽车防撞雷达系统的性能.

  13. Hybrid bidirectional radio-over-fiber-based orthogonal frequency division multiple access-passive optical network supporting 60/120 GHz using offset quadrate phase shift keying

    Zhang, Chongfu; Chen, Chen; Qiu, Kun

    2015-09-01

    A hybrid bidirectional orthogonal frequency division multiple access-passive optical network (OFDMA-PON) based on offset quadrate phase shift keying (OQPSK) to support 60- and 120-GHz radio-over-fiber system is proposed. The system can support wired/wireless applications and enable the dynamic bandwidth allocation according to a subscriber's application. It is successfully achieved by using the millimeter waves (MMWs) generation and the carrier-reuse technique. In the proposed scheme, the MMW bands used for downlink (DL) and uplink transmissions are generated at the optical line terminal by the dual-arm Mach-Zehnder modulators. Both 60- and 120-GHz MMWs are obtained for the transmission of the high bit-rate services in source-free optical network units (ONUs), only using a single 15-GHz sinusoidal wave source. The Rayleigh backscattering effect is considered in the proposed OQPSK-based OFDMA-PON. For DL transmission over a 30-km single-mode fiber, the power penalties are less than 0.8 and 1 dB for the OQPSK-OFDM wired data at 10 Gb/s and the OQPSK-OFDM wireless data at 5 Gb/s, respectively.

  14. THE EFFECT INDUCED BY MILLIMETER WAVES WITH THE FREQUENCY 53.33 GHZ ON SACCHAROMYCES CEREVISIAE CNMN-Y-18 YEAST STRAIN

    Agafia Usatîi

    2015-04-01

    Full Text Available The effect of extremely high frequency electromagnetic waves on the biosynthetic activity of Saccharomyces cerevisiae CNMN-Y-18 yeast strain in dependence on the duration of irradiation was studied. The maximum amount of biomass, protein, carbohydrates, mannoproteins and catalase has been showed to accumulate when the yeast cells were irradiated with a frequency f = 53.33 GHz for 10 minutes. High degree of dependence between the content of cellular components (a correlation coefficient between R2 = 0.875 and 0.926 it has been shown which demonstrates that biosynthetic processes were influenced by the same phenomenon - millimeter waves. A procedure for increasing of mannoprotein content in yeasts with the utilization of extremely high frequency waves has been proposed in this study.

  15. Relationship between peak spatial-averaged specific absorption rate and peak temperature elevation in human head in frequency range of 1–30 GHz

    Morimoto, Ryota; Laakso, Ilkka; De Santis, Valerio; Hirata, Akimasa

    2016-07-01

    This study investigates the relationship between the peak temperature elevation and the peak specific absorption rate (SAR) averaged over 10 g of tissue in human head models in the frequency range of 1–30 GHz. As a wave source, a half-wave dipole antenna resonant at the respective frequencies is located in the proximity of the pinna. The bioheat equation is used to evaluate the temperature elevation by employing the SAR, which is computed by electromagnetic analysis, as a heat source. The computed SAR is post-processed by calculating the peak spatial-averaged SAR with six averaging algorithms that consider different descriptions provided in international guidelines and standards, e.g. the number of tissues allowed in the averaging volume, different averaging shapes, and the consideration of the pinna. The computational results show that the SAR averaging algorithms excluding the pinna are essential when correlating the peak temperature elevation in the head excluding the pinna. In the averaging scheme considering an arbitrary shape, for better correlation, multiple tissues should be included in the averaging volume rather than a single tissue. For frequencies higher than 3–4 GHz, the correlation for peak temperature elevation in the head excluding the pinna is modest for the different algorithms. The 95th percentile value of the heating factor as well as the mean and median values derived here would be helpful for estimating the possible temperature elevation in the head.

  16. Photonic filtering of microwave signals in the frequency range of 0.01-20 GHz using a Fabry-Perot filter

    We demonstrate experimentally the efficiency of tuning of a photonic filter in the frequency range of 0.01 to 20 GHz. The presented work combines the use of a multimode optical source associated with a dispersive optical fiber to obtain the filtering effect. Tunability effect is achieved by the use of a Fabry-Perot filter that allows altering the spectral characteristics of the optical source. Experimental results are validated by means of numerical simulations. The scheme here proposed has a potential application in the field of optical telecommunications.

  17. Planck intermediate results: VII. Statistical properties of infrared and radio extragalactic sources from the Planck Early Release Compact Source Catalogue at frequencies between 100 and 857 GHz

    Delabrouille, J.; Ganga, K.; Giraud-Héraud, Y.;

    2013-01-01

    We make use of the Planck all-sky survey to derive number counts and spectral indices of extragalactic sources-infrared and radio sources-from the Planck Early Release Compact Source Catalogue (ERCSC) at 100 to 857 GHz (3 mm to 350 μm). Three zones (deep, medium and shallow) of approximately...... Planck High Frequency Instrument, all the sources have been classified as either dust-dominated (infrared galaxies) or synchrotron-dominated (radio galaxies) on the basis of their spectral energy distributions (SED). Our sample is thus complete, flux-limited and color-selected to differentiate between...

  18. Continuous-Wave Operation of a Frequency-Tunable 460-GHz Second-Harmonic Gyrotron for Enhanced Nuclear Magnetic Resonance

    Torrezan, Antonio C.; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Griffin, Robert G.; Barnes, Alexander B.

    2010-01-01

    The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE11,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnet...

  19. Astrometrically Registered Simultaneous Observations of the 22 GHz H$_2$O and the 43GHz SiO masers towards R Leonis Minoris using KVN and Source/Frequency Phase Referencing

    Dodson, Richard; Jung, Tae-Hyun; Sohn, Bong-Won; Byun, Do-Young; Cho, Se-Hyung; Lee, Sang-Sung; Kim, Jongsoo; Kim, Kee-Tae; Oh, Chung-Sik; Han, Seog-Tae; Je, Do-Heung; Chung, Moon-Hee; Wi, Seog-Oh; Kang, Jiman; Lee, Jung-Won; Chung, Hyunsoo; Kim, Hyo-Ryoung; Kim, Hyun-Goo; Lee, Chang-Hoon; Roh, Duk-Gyoo; Oh, Se-Jin; Yeom, Jae-Hwan; Song, Min-Gyu; Kang, Yong-Woo

    2014-01-01

    Oxygen-rich Asymptotic Giant Branch (AGB) stars can be intense emitters of SiO ($v$=1 and 2, J=1$\\rightarrow$0) and H$_2$O maser lines at 43 and 22 GHz, respectively. VLBI observations of the maser emission provide a unique tool to probe the innermost layers of the circumstellar envelopes in AGB stars. Nevertheless, the difficulties in achieving astrometrically aligned \\water\\ and $v$=1 and $v$=2 SiO maser maps have traditionally limited the physical constraints that can be placed on the SiO maser pumping mechanism. We present phase referenced simultaneous spectral-line VLBI images for the SiO $v$=1 and $v$=2, J=1$\\rightarrow$0, and H$_2$O maser emission around the AGB star R\\,LMi, obtained from the Korean VLBI Network (KVN). The simultaneous multi-channel receivers of the KVN offer great possibilities for astrometry in the frequency domain. With this facility we have produced images with bona-fide absolute astrometric registration between high frequency maser transitions of different species to provide the p...

  20. Flexible electromagnetic wave sensor operating at GHz frequencies for instantaneous concentration measurements of NaCl, KCl, MnCl2 and CuCl solutions

    A novel electromagnetic wave sensor operating at GHz frequencies for real-time chlorides concentration analysis is reported. The sensor response to deionized water, NaCl, KCl, MnCl2 and CuCl solutions at various concentrations was tested. The sensing element, in the form of a silver pattern antenna that emits an electromagnetic field, was printed on a polyimide flexible laminate substrate to form a sensor to suit a broad range of applications, where a sensor could be placed in water reservoirs or fluid-carrying pipes for continuous analysis. The developed system confirmed the viability of using microwaves for real-time chloride solutions monitoring as the reflected signals represented by S11 parameters were unique with clearly observed shifts in the resonant frequencies and amplitude changes when placed in direct contact with 20 µl of each solution. (paper)

  1. A stabilized 18 GHz chip-scale optical frequency comb at 2.8x10-16 relative inaccuracy

    Huang, S.-W.; Yang, J.; Yu, M.; McGuyer, B. H.; Kwong, D. -L.; Zelevinsky, T.; Wong, C. W.

    2015-01-01

    Optical frequency combs, coherent light sources that connect optical frequencies with microwave oscillations, have become the enabling tool for precision spectroscopy, optical clockwork and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but four-wave-mixing in high-Q resonators have emerged as alternative platforms. Here we report the generation and full stabilization of CMOS-compatible optical frequency combs. The spira...

  2. Theoretical and experimental study of two-frequency solid-state lasers in the GHz to THz ranges. Opto-microwave applications waves

    We explored some new features of single- and dual-frequency solid-state lasers oscillating in continuous-wave or pulsed regimes. First, we have developed some techniques to optimise the characteristics of pulsed lasers. A weak modulation of the pump power made it possible to obtain a stable repetition rate with a relative stability of 10-6. The pulse duration was continuously controlled from ten nanoseconds to a few hundreds nanoseconds by three different methods: adjustment of the laser beam diameter in the absorber, adjustment of the pump beam diameter in the active medium, and, in particular, the use of forked eigenstates in a two-axis laser. Moreover, the forked eigenstates allows to increase the pulse energy by coherent addition of the pulses. A compact two-frequency Nd:YAG-Cr:YAG laser with a beat note frequency continuously adjustable up to 2,7 GHz was demonstrated. The two-frequency pulses are ideal sources to meet various needs of applications such as the Doppler lidar-radar. Moreover, we show that two-frequency pulses at 1,55 μm can be obtained by using a new c-cut Co:ASL saturable absorber in an Er-Yb:glass laser. These pulses are perfectly adapted to free-space detection systems requiring eye safety. The coherence time of the beat note in these lasers was also studied: it is limited by the pulse duration. A new technique of modulating the pump power of a solid-state laser at frequencies close to its relaxation oscillation frequency was studied and made it possible to generate a beat note coherence from pulse to pulse. Frequency conversion techniques using the nonlinear optical effects make it possible to obtain tunable two-frequency sources in the visible spectrum. Green and red two-frequency pulses were obtained by using different conversion techniques, intra-cavity or extra-cavity. A two-frequency THz source in the red spectrum was also obtained by doubling the frequencies of a two-frequency THz Er-Yb:glass laser using a mixed fan-out PPLN crystal

  3. Direct generation of 12.5-GHz-spaced optical frequency comb with ultrabroad coverage in near-infrared region by cascaded fiber configuration.

    Kashiwagi, Ken; Kurokawa, Takashi; Okuyama, Yasushi; Mori, Takahiro; Tanaka, Yosuke; Yamamoto, Yoshinori; Hirano, Masaaki

    2016-04-18

    We generated a 12.5-GHz-spacing optical frequency comb that can be resolved over 100 THz, from 1040 to 1750 nm, without spectral mode filtering. To cover such a broad spectrum, we used electro-optic modulation of single frequency light and line-by-line pulse synthesis to produce a clear pulse train and subsequent spectral broadening in highly nonlinear fibers (HNLFs). We numerically and experimentally investigated a configuration of the HNLFs and find that a two-stage broadening through different HNLFs is required when using limited pulse energy at a high repetition rate. We designed and fabricated solid silica-based HNLFs with small zero-dispersion wavelengths to obtain strong spectral broadening, especially at the shorter wavelengths. The individual lines of the proposed frequency comb are resolvable with high contrast over the entire spectral range. The results described in this paper should lead to the development of multicarrier sources for wavelength-division-multiplexing communication and super-multi-point frequency calibration for spectrometers, especially in astrophysics. PMID:27137251

  4. Electromagnetic energy absorption potential and microwave heating capacity of SiC thin films in the 1-16 GHz frequency range

    We report on the electromagnetic (EM) absorption potential and microwave heating capacity of amorphous hydrogenated silicon carbide thin films (a-SiC:H) in the 1-16 GHz frequency domain. a-SiC:H thin films with typical thickness of 1 μm were deposited by plasma enhanced chemical vapor deposition on [1 0 0] undoped silicon substrates, and exhibit a deep EM absorption - up to 96% of the total EM energy irradiation - which is systematically converted into heat. Two-wavelength pyrometer tests show that temperatures exceeding 2000 K can be reached in a very short time, less than 100 s exposure to microwaves, showing a promising potential for specific microwave heating applications.

  5. Dosimetry of a set-up for the exposure of newborn mice to 2.45-GHz WiFi frequencies

    This work describes the dosimetry of a two waveguide cell system designed to expose newborn mice to electromagnetic fields associated with wireless fidelity signals in the frequency band of 2.45 GHz. The dosimetric characterisation of the exposure system was performed both numerically and experimentally. Specific measures were adopted with regard to the increase in both weight and size of the biological target during the exposure period. The specific absorption rate (SAR, W kg-1) for 1 W of input power vs. weight curve was assessed. The curve evidenced an SAR pattern varying from -1 to > 6 W kg-1 during the first 5 weeks of the life of mice, with a peak resonance phenomenon at a weight around 5 g. This curve was used to set the appropriate level of input power during experimental sessions to expose the growing mice to a defined and constant dose. (authors)

  6. Research and Development of 2-frequency (110/138 GHz FADIS for JT-60SA ECHCD system

    Idei H.

    2015-01-01

    Full Text Available A FAst DIrectional Switch (FADIS of 2-frequency (2-ƒ gyrotron system for the JT-60SA project is being developed under collaboration between Japan Atomic Energy Agency (JAEA and Kyushu University. At first, the frequency drift and dip in the gyrotron operation were measured to consider which kind of FADIS is preferred for application in the Electron Cyclotron Heating and Current Drive (ECHCD system for the JT- 60SA. Various types of the FADIS have been considered. A square corrugated waveguide diplexer system with double resonant rings was considered as one of the most attractive FADIS systems for stable high-power and long-pulse operations in the 2-ƒ JT-60SA ECHCD system.

  7. A 2-to-2.4-GHz differentially-tuned fractional-N frequency synthesizer for DVB tuner applications

    This paper describes the design of a fractional-N frequency synthesizer for digital video broadcasting-terrestrial (DVB-T) receivers. Transfer functions in differentially-tuned PLL are derived and loop parameters are designed. In addition, a fully-differential charge pump is presented. An 8/9 high speed prescaler is analyzed and the design considerations for the CML logic are also presented. Test results show that the RMS phase error is less than 0.70 in integer-N mode and less than 10 in fractional-N mode. The implemented frequency synthesizer draws 10 mA from a 1.8-V supply while occupying a die area of about 1-mm2 in a 0.18-μm CMOS process.

  8. A 2-to-2.4-GHz differentially-tuned fractional-N frequency synthesizer for DVB tuner applications

    Meng Lingbu; Lu Lei; Zhao Wei; Tang Zhangwen, E-mail: zwtang@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2010-07-15

    This paper describes the design of a fractional-N frequency synthesizer for digital video broadcasting-terrestrial (DVB-T) receivers. Transfer functions in differentially-tuned PLL are derived and loop parameters are designed. In addition, a fully-differential charge pump is presented. An 8/9 high speed prescaler is analyzed and the design considerations for the CML logic are also presented. Test results show that the RMS phase error is less than 0.7{sup 0} in integer-N mode and less than 1{sup 0} in fractional-N mode. The implemented frequency synthesizer draws 10 mA from a 1.8-V supply while occupying a die area of about 1-mm{sup 2} in a 0.18-{mu}m CMOS process.

  9. A 2-to-2.4-GHz differentially-tuned fractional-N frequency synthesizer for DVB tuner applications

    Lingbu, Meng; Lei, Lu; Wei, Zhao; Zhangwen, Tang

    2010-07-01

    This paper describes the design of a fractional-N frequency synthesizer for digital video broadcasting-terrestrial (DVB-T) receivers. Transfer functions in differentially-tuned PLL are derived and loop parameters are designed. In addition, a fully-differential charge pump is presented. An 8/9 high speed prescaler is analyzed and the design considerations for the CML logic are also presented. Test results show that the RMS phase error is less than 0.7° in integer-N mode and less than 1° in fractional-N mode. The implemented frequency synthesizer draws 10 mA from a 1.8-V supply while occupying a die area of about 1-mm2 in a 0.18-μm CMOS process.

  10. Escherichia coli membrane-associated energy-dependent processes and sensitivity toward antibiotics changes as responses to low-intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies.

    Torgomyan, Heghine; Trchounian, Armen

    2012-04-01

    Escherichia coli K-12(λ) was sensitive toward low-intensity (non-thermal, flux capacity 0.06 mW cm(-2)) electromagnetic irradiation (EMI) of extremely high frequency-70.6 and 73 GHz. 1 h exposure to EMI markedly depressed growth and cell viability of bacteria. Membrane-associated processes-total H(+) efflux and H(2) evaluation by whole cells during glucose fermentation were shown to be lowered as well. At the same time, the F(0)F(1)-ATPase activity of membrane vesicles was little depressed with 70.6 GHz irradiation only. This finding was in conformity with non-changed N,N'-dicyclohexylcarbodiimide-sensitive H(+) efflux. Furthermore, for understanding the different frequencies action mechanisms, the effects of antibiotics (chloramphenicol, ceftriaxone, kanamycin, and tetracycline) on irradiated cells growth and survival were determined. EMI with the frequencies of 70.6 and 73 GHz as with 51.8 and 53.0 GHz enhanced the sensitivity of bacteria toward antibiotics, but comparison revealed that each frequency had a different portion. Probably, EMI of specific frequency triggered changes in biological processes and afterward in growth and viability of bacteria, creating conditions when the action of antibiotics became facilitated. PMID:22101511

  11. 10–25 GHz frequency reconfigurable MEMS 5-bit phase shifter using push–pull actuator based toggle mechanism

    This paper presents a frequency tunable 5-bit true-time-delay digital phase shifter using radio frequency microelectromechanical system (RF MEMS) technology. The phase shifter is based on the distributed MEMS transmission line (DMTL) concept utilizing a MEMS varactor. The main source of frequency tuning in this work is a bridge actuation mechanism followed by capacitance variation. Two stages of actuation mechanisms (push and pull) are used to achieve a 2:1 tuning ratio. Accurate control of the actuation voltage between the pull to push stages contributes differential phase shift over the band of interest. The functional behavior of the push–pull actuation over the phase shifter application is theoretically established, experimentally investigated and validated with simulation. The phase shifter is fabricated monolithically using a gold based surface micromachining process on an alumina substrate. The individual primary phase-bits (11.25°/22.5°/45°/90°/180°) that are the fundamental building blocks of the complete 5-bit phase shifter are designed, fabricated and experimentally characterized from 10–25 GHz for specific applications. Finally, the complete 5-bit phase shifter demonstrates an average phase error of 4.32°, 2.8°, 1° and 1.58°, an average insertion loss of 3.76, 4.1, 4.2 and 4.84 dB and an average return loss of 11.7, 12, 14 and 11.8 dB at 10, 12, 17.2 and 25 GHz, respectively. To the best of the authors’ knowledge, this is the first reported band tunable stand alone 5-bit phase shifter in the literature which can work over the large spectrum for different applications. The total area of the 5-bit phase shifter is 15.6 mm2. Furthermore, the cold-switched reliability of the unit cell and the complete 5-bit MEMS phase shifter are extensively investigated and presented. (paper)

  12. 10-25 GHz frequency reconfigurable MEMS 5-bit phase shifter using push-pull actuator based toggle mechanism

    Dey, Sukomal; Koul, Shiban K.

    2015-06-01

    This paper presents a frequency tunable 5-bit true-time-delay digital phase shifter using radio frequency microelectromechanical system (RF MEMS) technology. The phase shifter is based on the distributed MEMS transmission line (DMTL) concept utilizing a MEMS varactor. The main source of frequency tuning in this work is a bridge actuation mechanism followed by capacitance variation. Two stages of actuation mechanisms (push and pull) are used to achieve a 2:1 tuning ratio. Accurate control of the actuation voltage between the pull to push stages contributes differential phase shift over the band of interest. The functional behavior of the push-pull actuation over the phase shifter application is theoretically established, experimentally investigated and validated with simulation. The phase shifter is fabricated monolithically using a gold based surface micromachining process on an alumina substrate. The individual primary phase-bits (11.25°/22.5°/45°/90°/180°) that are the fundamental building blocks of the complete 5-bit phase shifter are designed, fabricated and experimentally characterized from 10-25 GHz for specific applications. Finally, the complete 5-bit phase shifter demonstrates an average phase error of 4.32°, 2.8°, 1° and 1.58°, an average insertion loss of 3.76, 4.1, 4.2 and 4.84 dB and an average return loss of 11.7, 12, 14 and 11.8 dB at 10, 12, 17.2 and 25 GHz, respectively. To the best of the authors’ knowledge, this is the first reported band tunable stand alone 5-bit phase shifter in the literature which can work over the large spectrum for different applications. The total area of the 5-bit phase shifter is 15.6 mm2. Furthermore, the cold-switched reliability of the unit cell and the complete 5-bit MEMS phase shifter are extensively investigated and presented.

  13. Analysing limits for human exposure to electromagnetic fields in accordance with ITU- k.52 standard for frequencies between 10 khz and 3 GHz in urban areas of Bucaramanga

    José de Jesús Rugeles Uribe

    2010-04-01

    Full Text Available This article presents an overview of the results obtained from testing the limits of human exposure to 10KHz to 3GHZ frequencies in the city of Bucaramanga (Colombia, taking into account decree 195-2005 approved by the Colombian Ministry of Communications, based on International Telecommunication Union (ITU recommendation K.52. Measuring levels of exposure to electromagnetic radiation at three chosen locations in the city considered to be sensitive did not reveal that exposure limits were being exceeded. Mobile phone, modulated amplitude emission, frequency modulation and television bands installed at the sites several years ago were also measured. Levels ob-tained from electric field strength exceeded 100 dBuV / m in all cases, maximum value being 139 dBuV / m. Levels were well below exposure limits established by the K-52 rule. The highest levels for the general public’s exposure were 1.74964% in the AM band and 0.006408% for the cellular band between 869 and 894 MHz. This article also contains a description of the modules, exposure limits, acquisition and geo-positioning using the EspecVIEW tool designed for performing several types of measurements by Ministry officials and used in this study.

  14. FDTD calculation of whole-body average SAR in adult and child models for frequencies from 30 MHz to 3 GHz

    Due to the difficulty of the specific absorption rate (SAR) measurement in an actual human body for electromagnetic radio-frequency (RF) exposure, in various compliance assessment procedures the incident electric field or power density is being used as a reference level, which should never yield a larger whole-body average SAR than the basic safety limit. The relationship between the reference level and the whole-body average SAR, however, was established mainly based on numerical calculations for highly simplified human modelling dozens of years ago. Its validity is being questioned by the latest calculation results. In verifying the validity of the reference level with respect to the basic SAR limit for RF exposure, it is essential to have a high accuracy of human modelling and numerical code. In this study, we made a detailed error analysis in the whole-body average SAR calculation for the finite-difference time-domain (FDTD) method in conjunction with the perfectly matched layer (PML) absorbing boundaries. We derived a basic rule for the PML employment based on a dielectric sphere and the Mie theory solution. We then attempted to clarify to what extent the whole-body average SAR may reach using an anatomically based Japanese adult model and a scaled child model. The results show that the whole-body average SAR under the ICNIRP reference level exceeds the basic safety limit nearly 30% for the child model both in the resonance frequency and 2 GHz band

  15. A 3.1-4.8 GHz transmitter with a high frequency divider in 0.18 μm CMOS for OFDM-UWB

    Zheng Renliang; Ren Junyan; Li Wei; Li Ning

    2009-01-01

    A fully integrated low power RF transmitter for a WiMedia 3.1-4.8 GHz multiband orthogonal frequency division multiplexing ultra-wideband system is presented. With a separate transconductance stage, the quadrature up-conversion modulator achieves high linearity with low supply voltage. The co-design of different resonant frequencies of the modulator and the differential to single (D2S) converter ensures in-band gain flatness. By means of a series inductor peaking technique, the D2S converter obtains 9 dB more gain without extra power consumption. A divided-by-2 divider is used for carrier signal generation. The measurement results show an output power between -10.7 and -3.1 dBm with 7.6 dB control range, an OIP3 up to 12 dBm, a sideband rejection of 35 dBc and a carrier rejection of 30 dBc. The ESD protected chip is fabricated in the Jazz 0.18/zm RF CMOS process with an area of 1.74 mm~2 and only consumes 32 mA current (at 1.8 V) including the test associated parts.

  16. The contribution of microbunching instability to solar flare emission in the GHz to THz range of frequencies

    Michael Klopf, J. [Department of Applied Science, College of William and Mary, McGlothlin-Street Hall, Williamsburg, VA 23187 (United States); Kaufmann, Pierre; Raulin, Jean-Pierre; Szpigel, Sérgio [Centro de Rádio-Astronomia e Astrofísica Mackenzie, Escola de Engenharia, Universidade Presbiteriana Mackenzie, Rua Consolação 896, São Paulo, SP 01302-907 (Brazil)

    2014-08-10

    Recent solar flare observations in the sub-terahertz range have provided evidence of a new spectral component with fluxes increasing for larger frequencies, separated from the well-known microwave emission that maximizes in the gigahertz range. Suggested interpretations explain the terahertz spectral component but do not account for the simultaneous microwave component. We present a mechanism for producing the observed 'double spectra'. Based on coherent enhancement of synchrotron emission at long wavelengths in laboratory accelerators, we consider how similar processes may occur within a solar flare. The instability known as microbunching arises from perturbations that produce electron beam density modulations, giving rise to broadband coherent synchrotron emission at wavelengths comparable to the characteristic size of the microbunch structure. The spectral intensity of this coherent synchrotron radiation (CSR) can far exceed that of the incoherent synchrotron radiation (ISR), which peaks at a higher frequency, thus producing a double-peaked spectrum. Successful CSR simulations are shown to fit actual burst spectral observations, using typical flaring physical parameters and power-law energy distributions for the accelerated electrons. The simulations consider an energy threshold below which microbunching is not possible because of Coulomb repulsion. Only a small fraction of the radiating charges accelerated to energies above the threshold is required to produce the microwave component observed for several events. The ISR/CSR mechanism can occur together with other emission processes producing the microwave component. It may bring an important contribution to microwaves, at least for certain events where physical conditions for the occurrence of the ISR/CSR microbunching mechanism are possible.

  17. Compact MIMO Microstrip Antennas for USB Dongle Operating in 2.5–2.7 GHz Frequency Band

    Vladimir Ssorin

    2012-01-01

    Full Text Available This paper considers design of microstrip MIMO antennas for an LTE/WiMAX USB dongle operating in the 2.5–2.7 GHz frequency band. The MIMO system includes two antenna elements with an additional requirement of high isolation between them that is especially difficult to realize due to size limitations of a USB dongle. Three approaches to achieve the needed system characteristics using microstrip PCB antennas are proposed. For the first design, high port-to-port isolation is achieved by using a decoupling techniques based on a direct connection of the antenna elements. For the second approach, high port-to-port isolation of the MIMO antenna system is realized by a lumped decorrelation capacitance between antenna elements feeding points. The third proposed antenna system does not use any special techniques, and high port-to-port isolation is achieved by using only the properties of a developed printed inverted-F antenna element. The designed MIMO antenna systems have the return loss S11 and the insertion loss S21 bandwidths of more than 200 MHz at the −8 dB level with the correlation coefficient lower than 0.1 and exhibit pattern diversity when different antenna elements are excited. Experimental measurements of the fabricated antenna systems proved the characteristics obtained from electromagnetic simulation.

  18. Performance Analysis of OFDM 60GHz System and SC-FDE 60GHz System

    Han Xueyan

    2016-01-01

    Full Text Available In this paper, the performance of 60GHz wireless communication system with SC and OFDM is studied, the models of OFDM 60GHz system and SC 60GHz frequency domain equalization (SC-FDE system are established, and the bit error rate (BER performance of OFDM 60GHz system and SC-FDE 60GHz system in 802.15.3c channels is compared. The simulation results show that SC-FDE 60GHz system has a slight advantage over OFDM system in line-of-sight (LOS channels, while OFDM 60GHz system has a slight advantage over SC-FDE system in non-line-of-sight (NLOS channels. For 60GHz system, OFDM 60GHz system has a slight advantage over SC-FDE system in overcoming multipath fading, but the performance of both is close whether in the LOS or NLOS case.

  19. Low-intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies enhances the effects of disulfide bonds reducer on Escherichia coli growth and affects the bacterial surface oxidation-reduction state

    Torgomyan, Heghine [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia); Trchounian, Armen, E-mail: Trchounian@ysu.am [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia)

    2011-10-14

    Highlights: {yields} Low intensity 70.6 and 73 GHz electromagnetic irradiation (EMI) strongly suppressed Escherichia coli growth at 73 GHz and pH 7.3. {yields} Reducer DL-dithiothreitol had bactericidal effect and disturbed the SH-groups number. {yields} EMI enhanced E. coli sensitivity toward dithiothreitol. {yields} EMI decreased the SH-groups number of membrane disturbed by ATP and N,N'-dicyclohexycarbodiimide. {yields} The changed membrane oxidation-reduction state could be the primary mechanisms in EMI effects. -- Abstract: Low-intensity electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies (flux capacity - 0.06 mW cm{sup -2}) had bactericidal effects on Escherichia coli. This EMI (1 h) exposure suppressed the growth of E. coli K-12({lambda}). The pH value (6.0-8.0) did not significantly affect the growth. The lag-phase duration was prolonged, and the growth specific rate was inhibited, and these effects were more noticeable after 73 GHz irradiation. These effects were enhanced by the addition of DL-dithiothreitol (DTT), a strong reducer of disulfide bonds in surface membrane proteins, which in its turn also has bactericidal effect. Further, the number of accessible SH-groups in membrane vesicles was markedly decreased by EMI that was augmented by N,N'-dicyclohexycarbodiimide and DTT. These results indicate a change in the oxidation-reduction state of bacterial cell membrane proteins that could be the primary membranous mechanism in the bactericidal effects of low-intensity EMI of the 70.6 and 73 GHz frequencies.

  20. Low-intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies enhances the effects of disulfide bonds reducer on Escherichia coli growth and affects the bacterial surface oxidation-reduction state

    Highlights: → Low intensity 70.6 and 73 GHz electromagnetic irradiation (EMI) strongly suppressed Escherichia coli growth at 73 GHz and pH 7.3. → Reducer DL-dithiothreitol had bactericidal effect and disturbed the SH-groups number. → EMI enhanced E. coli sensitivity toward dithiothreitol. → EMI decreased the SH-groups number of membrane disturbed by ATP and N,N'-dicyclohexycarbodiimide. → The changed membrane oxidation-reduction state could be the primary mechanisms in EMI effects. -- Abstract: Low-intensity electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies (flux capacity - 0.06 mW cm-2) had bactericidal effects on Escherichia coli. This EMI (1 h) exposure suppressed the growth of E. coli K-12(λ). The pH value (6.0-8.0) did not significantly affect the growth. The lag-phase duration was prolonged, and the growth specific rate was inhibited, and these effects were more noticeable after 73 GHz irradiation. These effects were enhanced by the addition of DL-dithiothreitol (DTT), a strong reducer of disulfide bonds in surface membrane proteins, which in its turn also has bactericidal effect. Further, the number of accessible SH-groups in membrane vesicles was markedly decreased by EMI that was augmented by N,N'-dicyclohexycarbodiimide and DTT. These results indicate a change in the oxidation-reduction state of bacterial cell membrane proteins that could be the primary membranous mechanism in the bactericidal effects of low-intensity EMI of the 70.6 and 73 GHz frequencies.

  1. Rain and cloud effects on a satellite dual-frequency radar altimeter system operating at 13.5 and 35 GHz

    Walsh, E. J.; Monaldo, F. M.; Goldhirsh, J.

    1984-01-01

    The influence of clouds and rain on the return waveform signatures from satellite borne radar altimeters operating at 13.5 and 35 GHz are examined. It is specifically demonstrated that spatial nonuniformity in the cloud liquid water content or variations of the rain rate may result in significant distortions of the altimeter signature. The distorted signal is produced as a result of nonuniform attenuation occurring at the different range bins associated with the reflected signal. Determination of the mean sea height by employing tracking algorithms on these distorted echoes may result in gross errors. Although the influence of clouds on the altimeter signature and hence tracking precision is minimal at 13.5 GHz (e.g., less than 4 cm for a 1-s average), it may produce unacceptable mean sea level uncertainties at 35 GHz (e.g., 20 cm for a 1-s average) assuming a significant waveheight of 4 m. On the other hand, the signatures at both 13.5 GHz and 35 GHz become grossly distorted for rain rates of 10 mm/h and higher resulting in mean sea height errors of 46 and 65 cm, respectively, for significant wave heights of 2 m.

  2. Conducted noise suppression up to GHz range by spin-sprayed Ni0.2ZnxFe2.8-xO4 (x=0.3, 0.6) films having different natural resonance frequencies

    In order to apply to a novel, flexible type of GHz noise suppressors, we prepared Ni0.2ZnxFe2.8-xO4 films with x=0.3 and 0.6 and thicknesses of 2 and 5μm, by spin spray ferrite plating from an aqueous solution on polyimide sheets at 90 deg. C. Placing the films onto a microstrip line, we measured transmission loss ΔPloss and reflection parameter S11 at 10MHz-10GHz. As x increased from 0.3 to 0.6, fr (natural resonance frequency) decreased from 350 to 50MHz, which resulted in decreasing fc (a frequency from which ΔPloss begins rising) from 400 to 100MHz. This means we can tune fc of the films by changing the Zn concentration x. At 8GHz, ΔPloss obtained by the ferrite films increased from 40% to 70% when their thickness increased from 2 to 5μm. We obtained S11loss=40%, which was as strong as that obtained by a commercially available composite sheet type noise suppressor of 25μm thickness that are made of ferromagnetic metal flakes embedded in a flexible polymer matrix. Moreover, ΔPloss by the ferrite film increased to 70% when the thickness was increased to 5μm. Therefore, our NiZn ferrite films are promising to be actually used as GHz noise suppressors with tunable working frequencies that exhibit stronger noise suppression than the commercialized composite type of noise suppressors

  3. The effects of low-intensity electromagnetic irradiation at the frequencies of 51.8 and 53 GHz and antibiotic ceftazidime on Lactobacillus acidophilus F0F1 ATP-ase activity

    The effects of low intensity electromagnetic irradiation (EMI) at the frequencies 51.8 and 53 GHz and antibiotic ceftazidime on N,N'-dicyclohexylcarbodiimide (DCCD), inhibited ATP-ase activity of Lactobacillus acidophilus membrane vesicles were investigated. It was shown that both frequencies decreased the ATP-ase activity, moreover, ceftazidime increase the sensitivity of cells to DCCD, inhibitor of the F0F1-ATP-ase. EMI combined with ceftazidime and DCCD markedly decreased the ATPase activity. The F0F1-ATP-ase is suggested can be a target for the effects observed

  4. 34 GHz pulsed magnicon project

    A high efficiency, high power magnicon amplifier at 34.272 GHz has been designed as a radiation source to drive a multi-TeV electron-positron linear collider. Simulations predict a peak output power of 45 MW in a 1.5 microsecond pulse with an efficiency of 45% and a gain of 55 dB. The amplifier is a frequency tripler, or third harmonic amplifier, in that the output frequency of 34.272 GHz is three times the input drive frequency of 11.424 GHz. Thus the rotating TM110 modes in the drive cavity, 3 gain cavities and 2 penultimate cavities are resonant near 11.424 GHz; and the rotating TM310 mode in the output cavity is resonant at 34.272 GHz. A 500 kV, 215 A high area compression electron gun will provide an electron beam with a diameter less then 1 mm. A superconducting solenoid magnet will provide a magnetic field of 13 kG in the deflection system and 23 kG in the output cavity. Simulation results for the operation of the entire magnicon amplifier (gun, magnetic system, RF system and collector) will be given, and the status described of critical hardware components

  5. Highly-efficient 1-GHz-repetition-frequency femtosecond Yb3+:KY(WO42 laser for super-continuum generation

    Leburn C.G.

    2013-03-01

    Full Text Available We present a 1.024-GHz-repetition-rate femtosecond Yb3+:KY(WO42 laser with 61% optical-to-optical efficiency and 69% slope efficiency, generating a supercontinuum of bandwidth 400 nm in silica photonic-crystal fibre. RIN measurements of the laser yielded values <0.1%.

  6. Contribution to the analysis and design of reflectarray antennas for reconfigurable beam applications at frequencies above 100 GHz using liquid crystal technology

    Pérez Palomino, Gerardo

    2015-01-01

    El trabajo contenido en esta tesis doctoral está encuadrado en el desarrollo de antenas reconfigurables electrónicamente capaces de proporcionar prestaciones competitivas a las aplicaciones cada vez más comunes que operan a frecuencias superiores a 60 GHz. En concreto, esta tesis se centra en el estudio, diseño, e implementación de las antenas reflectarray, a las que se introduce la tecnología de cristal líquido como elemento característico con el que se consigue reconfigurabilidad de haz de ...

  7. VALIDATION STUDY OF PATH LOSS MODELS ON WIMAX AT 2.6 GHZ FREQUENCY BAND IN SUBURBAN ENVIRONMENT FOR CELL SIZE PLANNING

    Pratibha Maina; Gopal Chandra Manna; Namrata Sahayam

    2014-01-01

    The radio wave propagation in form of path loss model plays very significant role in planning of anywireless communication network. Measurement of signal strength of OFDM driven WiMAX technology at 2.6 GHz band is taken in Suburban Town of India. The results are analyzed and compared with Empirical path loss models such as Hata-Okumura, Modified Hata and COST-231Hata. COST-231 model shows highest path loss for suburban environment. These analyzed results establish that COST-231 model is suita...

  8. Impact of High Power Interference Sources in Planning and Deployment of Wireless Sensor Networks and Devices in the 2.4 GHz Frequency Band in Heterogeneous Environments

    Francisco Falcone

    2012-11-01

    Full Text Available In this work, the impact of radiofrequency radiation leakage from microwave ovens and its effect on 802.15.4 ZigBee-compliant wireless sensor networks operating in the 2.4 GHz Industrial Scientific Medical (ISM band is analyzed. By means of a novel radioplanning approach, based on electromagnetic field simulation of a microwave oven and determination of equivalent radiation sources applied to an in-house developed 3D ray launching algorithm, estimation of the microwave oven’s power leakage is obtained for the complete volume of an indoor scenario. The magnitude and the variable nature of the interference is analyzed and the impact in the radio link quality in operating wireless sensors is estimated and compared with radio channel measurements as well as packet measurements. The measurement results reveal the importance of selecting an adequate 802.15.4 channel, as well as the Wireless Sensor Network deployment strategy within this type of environment, in order to optimize energy consumption and increase the overall network performance. The proposed method enables one to estimate potential interference effects in devices operating within the 2.4 GHz band in the complete scenario, prior to wireless sensor network deployment, which can aid in achieving the most optimal network topology.

  9. 105 GHz Notch Filter Design for Collective Thomson Scattering

    Furtula, Vedran; Michelsen, Poul; Leipold, Frank; Johansen, T.; Korsholm, Søren Bang; Meo, Fernando; Moseev, Dmitry; Nielsen, Stefan Kragh; Salewski, Mirko; Stejner Pedersen, Morten

    2011-01-01

    A millimeter-wave notch filter with 105-GHz center frequency, >20-GHz passband coverage, and 1-GHz rejection bandwidth has been constructed. The design is based on a fundamental rectangular waveguide with cylindrical cavities coupled by narrow iris gaps, i.e., small elongated holes of negligible...

  10. Vela X at 31 GHz

    Hales, A S; Alvarez, H; May, J; Bronfman, L; Readhead, A C; Pearson, T J; Mason, B S; Dodson, R

    2004-01-01

    We present observations of the Vela X region at 31 GHz using the Cosmic Background Imager (CBI). We find a strong compact radio source (5.9'x4.1', FWHM) about the Vela pulsar, which we associate with the Vela pulsar wind nebula (PWN) recently discovered at lower radio-frequencies. The CBI's 4' resolution for a 45' field of view allows the PWN to be studied in the large-scale context of Vela X. Filamentary structure in Vela X, which stands out in lower frequency maps, is very low-level at 31 GHz. By combining the 10 CBI channels, which cover 26-36 GHz, and 8.4 GHz archive data, we study the spectral energy distribution (SED) of the PWN and the brightest filaments. Our results show that the spectral index alpha (F_{nu} propto nu^alpha) of the PWN is flat, or even marginally positive, with a value of alpha_{8.4}^{31}=0.10+-0.06, while the Vela X filamentary structure has a negative spectral index of alpha_{8.4}^{31}=-0.28+-0.09. The SED inhomogeneity observed in Vela X suggests different excitation processes bet...

  11. Synchrotron Spectral Curvature from 22 MHZ to 23 GHZ

    Kogut, Alan J.

    2012-01-01

    We combine surveys of the radio sky at frequencies 22 MHz to 1.4 GHz with data from the ARCADE-2 instrument at frequencies 3 GHz to 10 GHz to characterize the frequency spectrum of diffuse synchrotron emission in the Galaxy. The radio spectrum steepens with frequency from 22 MHz to 10 GHz. The projected spectral index at 23 GHz derived from the low-frequency data agrees well with independent measurements using only data at frequencies 23 GHz and above. Comparing the spectral index at 23 GHz to the value from previously published analyses allows extension of the model to higher frequencies. The combined data are consistent with a power-law index beta = -2.64 +/-= 0.03 at 0.31 GHz, steepening by an amount of Delta-beta = 0.07 every octave in frequency. Comparison of the radio data to models including the cosmic-ray energy spectrum suggests that any break in the synchrotron spectrum must occur at frequencies above 23 GHz.

  12. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    Biri, S.; Kitagawa, A.; Muramatsu, M; Drentje, A. G.; Rácz, R.; Yano, K.; Kato, Y; Sasaki, N; Takasugi, W.

    2015-01-01

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide bandwidth...

  13. Recent Tests on 117.5 GHz and 170 GHz Gyrotrons

    Felch K.

    2015-01-01

    Full Text Available Two megawatt-class gyrotrons at frequencies of 117.5 GHz and 170 GHz have recently been fabricated and tested at CPI. The 117.5 GHz gyrotron was designed to produce up to 1.8 MW for 10-second pulses, and will be used for electron cyclotron heating and current drive on the DIII-D tokamak at General Atomics. The 170 GHz gyrotron is specified as a 500 kW CW system, but has been designed with the goal of generating up to 1 MW CW. Oak Ridge National Laboratory will use the gyrotron in ITER ECH transmission line testing.

  14. Recommended safety procedures for the installation and use of radiofrequency and microwave devices in the frequency range 10 MHz-300 GHz

    Studies of possible hazards to human health from exposure to radio frequency and microwave radiation show that there is a need for controls. Exposure to high levels of radio frequency and microwave radiation over prolonged periods can cause adverse health effects. The type and extent of injury depend not only on the intensity (strength) of the field and the exposure duration but also on various other factors such as the frequency of the radiation, type of modulation, polarization, and distance from the source. (auth)

  15. Delivering Microwave Spectroscopy to the Masses: a Design of a Low-Cost Microwave Spectrometer Operating in the 18-26 GHZ Frequency Range

    Steber, Amanda; Pate, Brooks

    2014-06-01

    Advances in chip-level microwave technology in the communications field have led to the possibilities of low cost alternatives for current Fourier transform microwave (FTMW) spectrometers. Many of the large, expensive microwave components in a traditional design can now be replaced by robust, mass market monolithic microwave integrated circuits (MMICs). "Spectrometer on a board" designs are now feasible that offer dramatic cost reduction for microwave spectroscopy. These chip-level components can be paired with miniature computers to produce compact instruments that are operable through USB. A FTMW spectrometer design using the key MMIC components that drive cost reduction will be presented. Two dual channel synthesizers (Valon Technology Model 5008), a digital pattern generator (Byte Paradigm Wav Gen Xpress), and a high-speed digitizer/arbitrary waveform generator combination unit (Tie Pie HS-5 530 XM) form the key components of the spectrometer for operation in the 18-26.5 GHz range. The design performance is illustrated using a spectrometer that is being incorporated into a museum display for astrochemistry. For this instrument a user interface, developed in Python, has been developed and will be shown.

  16. Electronic transport in boron carbides: temperature (4K-300K), frequency (0-1 GHz) and composition (B13C2-B4C) effects

    Boron carbide is a light ceramics of industrial interest. The equilibrium diagram reveals a large compositional range (B9C to B4C). The compositions close to the boundary B4C are obtained by pressing directly in graphite dies while the other compositions were obtained by using boron nitride lined graphite dies and boron additions to the commercial powders. The starting point of the present study was the idea to use the electrical transport properties as possible ways of characterising the industrial materials. We were thus led to measure at low temperatures dc and ac conductivity, dielectric constant and thermopower. The successful study of a measurement method for ac measurements between 10 KHz and 1 GHz and between 4 K and 300 K was one of the main experimental points of the present work. ac measurements have permitted a clear separation between bulk and grain boundary effects on the transport. The bulk results were analysed in terms of the usual conduction models in disordered solids (hopping, polarons...)

  17. Contactless Investigations of Yeast Cell Cultivation in the 7 GHz and 240 GHz Ranges

    Using a microfluidic system based on PTFE tubes, experimental results of contactless and label-free characterization techniques of yeast cell cultivation are presented. The PTFE tube has an inner diameter of 0.5 mm resulting in a sample volume of 2 μ1 for 1 cm sample length. Two approaches (at frequencies around 7 GHz and 240 GHz) are presented and compared in terms of sensitivity and applicability. These frequency bands are particularly interesting to gain information on the permittivity of yeast cells in Glucose solution. Measurements from 240 GHz to 300 GHz were conducted with a continuous wave spectrometer from Toptica. At 7 GHz band, measurements have been performed using a rat-race based characterizing system realized on a printed circuit board. The conducted experiments demonstrate that by selecting the phase as characterization parameter, the presented contactless and label-free techniques are suitable for cell cultivation monitoring in a PTFE pipe based microfluidic system.

  18. Transient DNA damage induced by high-frequency electromagnetic fields (GSM 1.8 GHz) in the human trophoblast HTR-8/SVneo cell line evaluated with the alkaline comet assay

    One of the most controversial issue regarding high-frequency electromagnetic fields (HF-EMF) is their putative capacity to affect DNA integrity. This is of particular concern due to the increasing use of HF-EMF in communication technologies, including mobile phones. Although epidemiological studies report no detrimental effects on human health, the possible disturbance generated by HF-EMF on cell physiology remains controversial. In addition, the question remains as to whether cells are able to compensate their potential effects. We have previously reported that a 1-h exposure to amplitude-modulated 1.8 GHz sinusoidal waves (GSM-217 Hz, SAR = 2 W/kg) largely used in mobile telephony did not cause increased levels of primary DNA damage in human trophoblast HTR-8/SVneo cells. Nevertheless, further investigations on trophoblast cell responses after exposure to GSM signals of different types and durations were considered of interest. In the present work, HTR-8/SVneo cells were exposed for 4, 16 or 24 h to 1.8 GHz continuous wave (CW) and different GSM signals, namely GSM-217 Hz and GSM-Talk (intermittent exposure: 5 min field on, 10 min field off). The alkaline comet assay was used to evaluate primary DNA damages and/or strand breaks due to uncompleted repair processes in HF-EMF exposed samples. The amplitude-modulated signals GSM-217 Hz and GSM-Talk induced a significant increase in comet parameters in trophoblast cells after 16 and 24 h of exposure, while the un-modulated CW was ineffective. However, alterations were rapidly recovered and the DNA integrity of HF-EMF exposed cells was similar to that of sham-exposed cells within 2 h of recovery in the absence irradiation. Our data suggest that HF-EMF with a carrier frequency and modulation scheme typical of the GSM signal may affect the DNA integrity.

  19. Radio frequency electromagnetic radiation (RF-EMR from GSM (0.9/1.8GHz mobile phones induces oxidative stress and reduces sperm motility in rats

    Maneesh Mailankot

    2009-06-01

    Full Text Available INTRODUCTION: Mobile phones have become indispensable in the daily lives of men and women around the globe. As cell phone use has become more widespread, concerns have mounted regarding the potentially harmful effects of RF-EMR from these devices. OBJECTIVE: The present study was designed to evaluate the effects of RF-EMR from mobile phones on free radical metabolism and sperm quality. MATERIALS AND METHODS: Male albino Wistar rats (10-12 weeks old were exposed to RF-EMR from an active GSM (0.9/1.8 GHz mobile phone for 1 hour continuously per day for 28 days. Controls were exposed to a mobile phone without a battery for the same period. The phone was kept in a cage with a wooden bottom in order to address concerns that the effects of exposure to the phone could be due to heat emitted by the phone rather than to RF-EMR alone. Animals were sacrificed 24 hours after the last exposure and tissues of interest were harvested. RESULTS: One hour of exposure to the phone did not significantly change facial temperature in either group of rats. No significant difference was observed in total sperm count between controls and RF-EMR exposed groups. However, rats exposed to RF-EMR exhibited a significantly reduced percentage of motile sperm. Moreover, RF-EMR exposure resulted in a significant increase in lipid peroxidation and low GSH content in the testis and epididymis. CONCLUSION: Given the results of the present study, we speculate that RF-EMR from mobile phones negatively affects semen quality and may impair male fertility.

  20. Measurements of the dielectric constant and dielectric loss at MHz and GHz frequencies for ionic exchange resin embedded in concrete and bitumen

    Dielectric measurements have been carried out on concrete and bitumen containing ion exchange resin. The results indicate that absorption of radio waves would not prohibit measurements being made on full size waste forms, except in the case of concrete at high frequencies. The results also indicate that dielectric measurements on wastes may provide information related to the water content of concrete and bitumen, and possibly also to the curing time of concrete. (Auth.)

  1. Measurement of the circular polarization of radio sources at frequencies of 0.63, 1.4, 5.0 and 8.9 GHz

    Circular polarization measurements were made with the Parkes 64 m telescope on 66 mainly extragalactic sources, 33 of which were studied at two or more frequencies. Circular polarization was definitely found in the eight quasistellar sources PKS0237-23, 0537-441, 1127-14, 1226+02 (3C273), 1253-05 (3C279), 2134+004, 2145+06 and 2345-16, as it was measured at the 4sigma level or higher in at least two observing sessions. For all eight sources the total power spectrum shows the effects of self-absorption. For none of the eight is there evidence of a reversal of the sense of polarization with frequency. For several of the sources of the degree of circular polarization changed by a factor >2 between observing sessions, while any accompanying change in total flux density was <20%. Instrumental effects are discussed in some detail. Fluctuations due to system noise provide the main limitation, but for strong sources uncertainties in the determination of the zero of polarization are important. (author)

  2. Gyrotrons for magnetic fusion applications at 110 GHz and 170 GHz

    Cahalan P.

    2012-09-01

    Full Text Available Two megawatt-class gyrotrons at frequencies of 110 GHz and 170 GHz have recently been fabricated at CPI. The 110 GHz gyrotron is designed to produce 1.2 MW of output power for 10-second pulses, and will be used for electron cyclotron heating and current drive on the DIII-D tokamak at General Atomics. This gyrotron has completed factory testing and has been delivered to General Atomics for installation and additional testing. The 170 GHz gyrotron, though specified as a 500 kW CW system, has been designed with the goal of generating up to 1 MW CW. Oak Ridge National Laboratory will use this gyrotron in ITER ECH transmission line testing. This gyrotron has been fabricated and is awaiting factory testing, Design features of each gyrotron are described, and test data for the 110 GHz gyrotron are presented.

  3. Millimeter wave transmission studies of YBa2Cu3O7-delta thin films in the 26.5 to 40.0 GHz frequency range

    Miranda, F. A.; Gordon, W. L.; Bhasin, K. B.; Heinen, V. O.; Warner, J. D.; Valco, G. J.

    1989-01-01

    Millimeter wave transmission measurements through YBa2Cu3O(7-delta) thin films on MgO, ZrO2 and LaAlO3 substrates, are reported. The films (approx. 1 micron) were deposited by sequential evaporation and laser ablation techniques. Transition temperatures T sub c, ranging from 89.7 K for the Laser Ablated film on LaAlO3 to approximately 72 K for the sequentially evaporated film on MgO, were obtained. The values of the real and imaginary parts of the complex conductivity, sigma 1 and sigma 2, are obtained from the transmission data, assuming a two fluid model. The BCS approach is used to calculate values for an effective energy gap from the obtained values of sigma sub 1. A range of gap values from 2 DELTA o/K sub B T sub c = 4.19 to 4.35 was obtained. The magnetic penetration depth is evaluated from the deduced values of sigma 2. These results are discussed together with the frequency dependence of the normalized transmission amplitude, P/P sub c, below and above T sub c.

  4. A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization

    Barnes, Alexander B.; Nanni, Emilio A.; Herzfeld, Judith; Griffin, Robert G.; Temkin, Richard J.

    2012-01-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementin...

  5. 38 GHz Antennas on Micromachined Silicon Substrates.

    Marcelli, Romolo; Dragoman, M.; Neculoiu, Dan; Giacomozzi, Flavio; Muller, Alexandru; Nitescu, N.

    2001-01-01

    A new configuration of a double folded double slot CPW feed micromachined antenna array was realized on a 1.5 µm thin three-layer dielectric membrane fabricated on a silicon substrate. The antenna was designed for an operating frequency of 38 GHz, and the double folded configuration was used for minimizing the membrane extension.

  6. Traveling-Wave Maser for 32 GHz

    Shell, James; Clauss, Robert

    2009-01-01

    The figure depicts a traveling-wave ruby maser that has been designed (though not yet implemented in hardware) to serve as a low-noise amplifier for reception of weak radio signals in the frequency band of 31.8 to 32.3 GHz. The design offers significant improvements over previous designs of 32-GHz traveling-wave masers. In addition, relative to prior designs of 32-GHz amplifiers based on high-electron-mobility transistors, this design affords higher immunity to radio-frequency interference and lower equivalent input noise temperature. In addition to the basic frequency-band and low-noise requirements, the initial design problem included a requirement for capability of operation in a closed-cycle helium refrigerator at a temperature .4 K and a requirement that the design be mechanically simplified, relative to prior designs, in order to minimize the cost of fabrication and assembly. Previous attempts to build 32- GHz traveling-wave masers involved the use of metallic slow-wave structures comprising coupled transverse electromagnetic (TEM)-mode resonators that were subject to very tight tolerances and, hence, were expensive to fabricate and assemble. Impedance matching for coupling signals into and out of these earlier masers was very difficult. A key feature of the design is a slow-wave structure, the metallic portions of which would be mechanically relatively simple in that, unlike in prior slow-wave structures, there would be no internal metal steps, irises, or posts. The metallic portions of the slow-wave structure would consist only of two rectangular metal waveguide arms. The arms would contain sections filled with the active material (ruby) alternating with evanescent-wave sections. This structure would be transparent in both the signal-frequency band (the aforementioned range of 31.8 to 32.3 GHz) and the pump-frequency band (65.75 to 66.75 GHz), and would impose large slowing factors in both frequency bands. Resonant ferrite isolators would be placed in the

  7. Low Cost Automated Module Assembly for 180 GHz Devices Project

    National Aeronautics and Space Administration — Emergence of Indium Phosphide IC's has made possible devices operating at frequencies up to 200GHZ and beyond. Building modules using these devices opens a goldmine...

  8. VLBI difference astrometry at 43GHz

    Guirado, J C; Pérez-Torres, M A; Ros, E

    2000-01-01

    From 43GHz VLBA observations of the pair of radio sources 1928+738 and2007+777 we have demonstrated the feasibility of precision phase-delaydifferential astrometric techniques at millimeter wavelengths. For a pair ofsources with 5 degrees separation and high antenna elevations, we have shownthat present astrometric models and millimeter arrays are advanced enough tomodel the differential phase-delay to within 2 picoseconds, less than one tenthof a phase-cycle at 43GHz. The root-mean-square of the differential phase-delayresiduals is dominated by the fluctuations of the atmospheric water vapor. Wehave determined the relative position of the observed sources with a precisiontwofold better than previous determinations at lower frequencies and, moreimportantly, largely free from ambiguous definitions of the reference point onthe structure of the radio sources. Our result makes 43GHz VLBI phase-delaydifferential astrometry an ideal tool to study the absolute kinematics of thehighly variable structures of regions n...

  9. A 75-116-Ghz LNA with 23-K Noise Temperature at 108 Ghz

    Varonen, Mikko; Reeves, Rodrigo; Kangaslahti, Pekka; Samoska, Lorene; Cleary, Kieran; Gawande, Rohit; Fung, Andy; Gaier, Todd; Weinreb, Sander; Readhead, Anthony C. S.; Sarkozy, Stephen; Lai, Richard

    2013-01-01

    In this paper we present the design and measurement results, both on-wafer and in package, of an ultra-low-noise and wideband monolithic microwave integrated circuit (MMIC) amplifier in the frequency range of 75 to 116 GHz. The three-stage amplifier packaged in a WR10 waveguide housing and fabricated using a 35-nm InP HEMT technology achieves a record noise temperature of 23 K at 108 GHz when cryogenically cooled to 27 K. The measured gain is 22 to 27 dB for frequency range of 75 to 116 GHz. Furthermore, the amplifier utilizes four finger devices with total gate width of 60 um resulting for improved linearity.

  10. Oscillations up to 712 GHz in InAs/AlSb resonant-tunneling diodes

    Brown, E. R.; Parker, C. D.; Mahoney, L. J.; Molvar, K. M.; Soderstrom, J. R.

    1991-01-01

    Oscillations have been obtained at frequencies from 100 to 712 GHz in InAs/AlSb double-barrier resonant-tunneling diodes at room temperature. The measured power density at 360 GHz was 90 W/sq cm, which is 50 times that generated by GaAs/AlAs diodes at essentially the same frequency. The oscillation at 712 GHz represents the highest frequency reported to date from a solid-state electronic oscillator at room temperature.

  11. Turn-over in pulsar spectra above 1 GHz

    Kijak, J.; Gupta, Y; Krzeszowski, K.

    2007-01-01

    We present the first direct evidence for turn-over in pulsar radio spectra at high frequencies. Two pulsars are now shown to have a turn-over frequency > 1GHz. We also find some evidence that the peak frequency of turn-over in pulsar spectra appears to depend on dispersion measure and pulsar age.

  12. SEVENTH HARMONIC 20 GHz CO-GENERATOR

    Hirshfield, Jay L

    2014-04-08

    To satisfy the need for multi-MW rf sources in frequency ranges where commercial sources do not exist, a study was undertaken on a class of devices based on gyro-harmonic frequency multiplication. This mechanism relies upon adding energy in gyrating motion to a linear electron beam that traverses a rotating-mode TE111-mode drive cavity in a dc magnetic field. The beam then drifts along the magnetic field into a second cavity, operating in the TEn11-mode tuned to the nth harmonic of the drive cavity. Studies of this configuration have been carried out for 2 < n < 7. Results are given for multi-MW, efficient operation of a 7th harmonic device operating at 20 GHz, and a 2nd harmonic device operating at 22.4 GHz.

  13. Design and Development of Low Pass Filter at 60 GHz

    Sanjeev Kumar Shah

    2013-07-01

    Full Text Available This paper describes the design and development of low pass filter (LPF at 60 GHz. The present design uses stepped impedance method in suspended strip line. The design is modeled and optimized using CST (Computer Simulation Technology microwave studio. The design of a filter types that Tchebysheve 0.1 dB ripple in the passband with the standard bandwidth of 2% and 30 dB attenuation at 94 GHz. The 60 GHz low pass filter exhibits an insertion loss of 1 dB with 3 dB relative bandwidth at a cut-off frequency of 60 GHz and the return loss is better than -18 dB at a cut-off frequency. The designed and fabricated low pass filter shows the good performance for planar integrated millimeter-wave circuits

  14. 60 Gbit/s 400 GHz Wireless Transmission

    Yu, Xianbin; Asif, Rameez; Piels, Molly;

    2015-01-01

    We experimentally demonstrate a 400 GHz carrier wireless transmission system with real-time capable detection and demonstrate transmission of a 60 Gbit/s signal derived from optical Nyquist channels in a 12.5 GHz ultra-dense wavelength division multiplexing (UD-WDM) grid and carrying QPSK...... modulation. This is the highest data rate demonstrated for carrier frequencies above 300 GHz and also validates the feasibility of bridging between next generation 100 GbE wired data streams and indoor wireless applications....

  15. A Low-jitter 2.5-to-10 GHz Clock Multiplier Unit in CMOS

    Beek, van, P.; Vaucher, C.S.; Leenaerts, D. M. W.; Klumperink, E.A.M.; Nauta, B.

    2003-01-01

    This paper demonstrates a low-jitter clock multiplier unit [1] that generates a 10 GHz output clock from a 2.5 GHz reference clock. An integrated 10 GHz LCoscillator is locked to the input clock, using a simple and fast phase detector circuit. This phase detector overcomes the speed limitation of a conventional tri-state Phase Frequency Detector, by eliminating an internal feedback loop. A frequency detector guarantees PLL locking without degenerating jitter performance. The clock multiplier ...

  16. A 94-GHz Millimeter-Wave Sensor for Speech Signal Acquisition

    Jianqi Wang; Hua Zhang; Huijun Xue; Hao Lv; Xiao Yu; Yang Zhang; Guohua Lu; Ying Tian; Sheng Li; Xijing Jing

    2013-01-01

    High frequency millimeter-wave (MMW) radar-like sensors enable the detection of speech signals. This novel non-acoustic speech detection method has some special advantages not offered by traditional microphones, such as preventing strong-acoustic interference, high directional sensitivity with penetration, and long detection distance. A 94-GHz MMW radar sensor was employed in this study to test its speech acquisition ability. A 34-GHz zero intermediate frequency radar, a 34-GHz superheterodyn...

  17. 60 GHz SIW Steerable Antenna Array in LTCC

    Bahram Sanadgol; Sybille Holzwarth; Peter Uhlig; Alberto Milano; Raft Popovich

    2012-01-01

    In this paper, we present a 60 GHz substrate-integrated waveguide fed-steerable low-temperature cofired ceramics array. The antenna is suitable for transmitting and receiving on the 60 GHz wireless personal area network frequency band. The wireless system can be used for HDTV, high-data-rate networking up to 4.5 GBit/s, security and surveillance, and similar applications.

  18. 60 GHz MAC Standardization: Progress and Way Forward

    2015-01-01

    Communication at mmWave frequencies has been the focus in the recent years. In this paper, we discuss standardization efforts in 60 GHz short range communication and the progress therein. We compare the available standards in terms of network architecture, medium access control mechanisms, physical layer techniques and several other features. Comparative analysis indicates that IEEE 802.11ad is likely to lead the short-range indoor communication at 60 GHz. We bring to the fore resolved and un...

  19. Above 8GHz Static T-Flip-Flop Operation using FT=22.9GHz GaAs MESFETs

    Riishøj, J; Danielsen, Per Lander

    1992-01-01

    A static SCFL Toggle Flip-Flop GaAs IC having maximum operating frequency of Fdiv=8.25GHz has been designed using a commercially available GaAs MESFET foundry service. The average Ft for the present wafer is Ft=22.9GHz giving a very high Fdiv/Ft-ratio of Fdiv/Ft=0.36. In addition output voltage...

  20. High performance 33.2 GHz gyroklystron

    The design for a high performance, 33.2 GHz three-cavity gyroklystron has been completed. The design modifies Varian's pioneering 28 GHz gyroklystron in order to suppress oscillation and yield higher gain and efficiency. Modifications include an additional buncher cavity, lower beam α, and a slight increase in frequency. Self-consistent simulation for an axial velocity spread of 7% and α = 1.5 predicts an output power of 250 kW with a saturated gain of 52 dB and an efficiency of 39%. An investigation of penultimate cavity detuning showed no improvement in efficiency for the above velocity spread. A synchronously tuned gyroklystron is currently being constructed

  1. 28 GHz Gyrotron ECRH Upgrade for LDX

    Michael, P. C.; Woskov, P. P.; Ellsworth, J. L.; Kesner, J.; Garnier, D. T.; Mauel, M. E.; Ellis, R. F.

    2009-11-01

    A 10 kW, CW, 28 GHz gyrotron is being implemented on LDX to increase the plasma density and to more fully explore the potential of high beta plasma stability in a dipole magnetic configuration. Higher density increases the heating of ions by thermal equilibration and allows for improved wave propagation in planned ICRF experiments. This represents over a 50% increase in the 17 kW ECRH from sources at 2.45, 6.4, and 10.5 GHz. The higher frequency will also make possible access to plasma densities of up to 10^13 cm-3. The 1 Tesla resonances are located above and below the floating coil near the dipole axial region. The gyrotron beam will be transmitted in TE01 mode in 32.5 mm diameter guide using one 90 bend and a short Tesla resonance region. A layout of the planned system will be presented.

  2. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    2010-10-01

    ... fundamental frequency following the provisions of § 15.31(m). (3) For systems operating in the 23.12-29.0 GHz... are used only for back-up assistance and that operate only when the vehicle is engaged in reverse. (1... emission appear shall be greater than 24.075 GHz. (4) These devices shall operate only when the vehicle...

  3. Imaging, Doppler, and spectroscopic radars from 95 to 700 GHz

    Cooper, Ken B.

    2016-05-01

    Imaging, Doppler, and spectroscopic radars from 95 to 700 GHz, all using the frequency-modulated continuous-wave technique, are in various stages of development for both defense and science applications at the Jet Propulsion Laboratory. For standoff security screening, a 340 GHz imaging radar now achieves an 8.3 Hz frame, and it has been tested using power-efficient MMIC-based active multiplier sources into its front end. That system evolved from a 680 GHz security radar platform, which has also been modified to operate in a Doppler mode for probing the dynamics of blowing sand and sensing small-amplitude target vibrations. Meanwhile, 95 and 183 GHz radars based on similar RF architectures are currently being developed to probe cometary jets in space and, using a differential absorption technique, humidity inside upper-tropospheric clouds.

  4. Low Noise Amplifier for 2.45 GHz Frequency Band at 0.18 μm CMOS Technology for IEEE Standard 802.11 b/g WLAN

    Viranjay M. Srivastava

    2012-08-01

    Full Text Available This paper presents the design of low noise amplifier (LNA at 2.45 GHz and integrated at 0.18 µm RF CMOS process technology. This type of LNA at 2.45 GHz is use in the Bluetooth receiver. The proposed method is useful to optimize noise performance and power gain while maintaining good input and output matching. The amplifier is designed to be used as first stage of a receiver for wireless communication. The main aim of designer is to achieve low noise figure with improved gain with the help of CMOS technology by using single stage n-MOS amplifier. The simulation results show a forward gain of 14.0 dB, a noise-figure of 0.5 dB and stability factor is approximate unity, in which the circuit operates at 14.2 mA drain current with supply voltage of 3.5 V and biasing voltage of 1.5 V.

  5. Microwave Radiometer - high frequency

    Oak Ridge National Laboratory — The Microwave Radiometer-High Frequency (MWRHF) provides time-series measurements of brightness temperatures from two channels centered at 90 and 150 GHz. These two...

  6. Gaussian entanglement distribution with GHz bandwidth

    Ast, Stefan; Mehmet, Moritz; Schnabel, Roman

    2016-01-01

    The distribution of Gaussian entanglement can be used to generate a mathematically-proven secure key for quantum cryptography. The distributed secret key rate is limited by the bandwidth of the nonlinear resonators used for entanglement generation, which is less than 100 MHz for current state-of-the-art setups. The development of an entanglement source with a higher bandwidth promises an increased measurement speed and a linear boost in the secure data rate. Here, we present the experimental realization of a continuous-variable entanglement source with a bandwidth of more than 1.25 GHz. The measured entanglement spectrum was quantified via the inseparability criterion introduced by Duan and coworkers with a critical value of 4 below which entanglement is certified. The measurements yielded an inseparability value of about 1.8 at a frequency of 300 MHz to about 2.8 at 1.2 GHz extending further to about 3.1 at 1.48 GHz. In the experiment we used two 2.6 mm long monolithic PPKTP crystal resonators to generate tw...

  7. High-purity 60GHz band millimeter-wave generation based on optically injected semiconductor laser under subharmonic microwave modulation.

    Fan, Li; Xia, Guangqiong; Chen, Jianjun; Tang, Xi; Liang, Qing; Wu, Zhengmao

    2016-08-01

    Based on an optically injected semiconductor laser (OISL) operating at period-one (P1) nonlinear dynamical state, high-purity millimeter-wave generation at 60 GHz band is experimentally demonstrated via 1/4 and 1/9 subharmonic microwave modulation (the order of subharmonic is with respect to the frequency fc of the acquired 60 GHz band millimeter-wave but not the fundamental frequency f0 of P1 oscillation). Optical injection is firstly used to drive a semiconductor laser into P1 state. For the OISL operates at P1 state with a fundamental frequency f0 = 49.43 GHz, by introducing 1/4 subharmonic modulation with a modulation frequency of fm = 15.32 GHz, a 60 GHz band millimeter-wave with central frequency fc = 61.28 GHz ( = 4fm) is experimentally generated, whose linewidth is below 1.6 kHz and SSB phase noise at offset frequency 10 kHz is about -96 dBc/Hz. For fm is varied between 13.58 GHz and 16.49 GHz, fc can be tuned from 54.32 GHz to 65.96 GHz under matched modulation power Pm. Moreover, for the OISL operates at P1 state with f0 = 45.02 GHz, a higher order subharmonic modulation (1/9) is introduced into the OISL for obtaining high-purity 60 GHz band microwave signal. With (fm, Pm) = (7.23 GHz, 13.00 dBm), a microwave signal at 65.07 GHz ( = 9fm) with a linewidth below 1.6 kHz and a SSB phase noise less than -98 dBc/Hz is experimentally generated. Also, the central frequency fc can be tuned in a certain range through adjusting fm and selecting matched Pm. PMID:27505789

  8. Phase Closure at 691 GHz using the Submillimeter Array

    Hunter, T R; Peck, A B; Christensen, R D; Blundell, R; Camacho, A; Patt, F; Sakamoto, K; Young, K H

    2007-01-01

    Phase closure at 682 GHz and 691 GHz was first achieved using three antennas of the Submillimeter Array (SMA) interferometer located on Mauna Kea, Hawaii. Initially, phase closure was demonstrated at 682.5 GHz on Sept. 19, 2002 using an artificial ground-based "beacon" signal. Subsequently, astronomical detections of both Saturn and Uranus were made at the frequency of the CO(6-5) transition (691.473 GHz) on all three baselines on Sept. 22, 2002. While the larger planets such as Saturn are heavily resolved even on these short baselines (25.2m, 25.2m and 16.4m), phase closure was achieved on Uranus and Callisto. This was the first successful experiment to obtain phase closure in this frequency band. The CO(6-5) line was also detected towards Orion BN/KL and other Galactic sources, as was the vibrationally-excited 658 GHz water maser line toward evolved stars. We present these historic detections, as well as the first arcsecond-scale images obtained in this frequency band.

  9. Rain rate and modeled fade distributions at 20 GHz and 30 GHz derived from five years of network rain gauge measurements

    Goldhirsh, Julius; Krichevsky, Vladimir; Gebo, Norman

    1992-08-01

    Five years of rain rate and modeled slant path attenuation distributions at 20 GHz and 30 GHz derived from a network of 10 tipping bucket rain gages was examined. The rain gage network is located within a grid 70 km north-south and 47 km east-west in the Mid-Atlantic coast of the United States in the vicinity of Wallops Island, Virginia. Distributions were derived from the variable integration time data and from one minute averages. It was demonstrated that for realistic fade margins, the variable integration time results are adequate to estimate slant path attenuations at frequencies above 20 GHz using models which require one minute averages. An accurate empirical formula was developed to convert the variable integration time rain rates to one minute averages. Fade distributions at 20 GHz and 30 GHz were derived employing Crane's Global model because it was demonstrated to exhibit excellent accuracy with measured COMSTAR fades at 28.56 GHz.

  10. 90 GHz AND 150 GHz OBSERVATIONS OF THE ORION M42 REGION. A SUBMILLIMETER TO RADIO ANALYSIS

    We have used the new 90 GHz MUSTANG camera on the Robert C. Byrd Green Bank Telescope (GBT) to map the bright Huygens region of the star-forming region M42 with a resolution of 9'' and a sensitivity of 2.8 mJy beam-1. Ninety GHz is an interesting transition frequency, as MUSTANG detects both the free-free emission characteristic of the H II region created by the Trapezium stars, normally seen at lower frequencies, and thermal dust emission from the background OMC1 molecular cloud, normally mapped at higher frequencies. We also present similar data from the 150 GHz GISMO camera taken on the IRAM 30 m telescope. This map has 15'' resolution. By combining the MUSTANG data with 1.4, 8, and 21 GHz radio data from the VLA and GBT, we derive a new estimate of the emission measure averaged electron temperature of Te = 11376 ± 1050 K by an original method relating free-free emission intensities at optically thin and optically thick frequencies. Combining Infrared Space Observatory-long wavelength spectrometer (ISO-LWS) data with our data, we derive a new estimate of the dust temperature and spectral emissivity index within the 80'' ISO-LWS beam toward Orion KL/BN, Td = 42 ± 3 K and β d = 1.3 ± 0.1. We show that both Td and β d decrease when going from the H II region and excited OMC1 interface to the denser UV shielded part of OMC1 (Orion KL/BN, Orion S). With a model consisting of only free-free and thermal dust emission, we are able to fit data taken at frequencies from 1.5 GHz to 854 GHz (350 μm).

  11. 50 MHz – 26,5 GHz Aralığında Çalışan Toplam Güç Radyometrenin Gerçekleştirilmesi ve Test Edilmesi - Realization and Test of The Total Power Radiometer Working Between 50MHz and 26.5 GHz Frequency Range

    Celep, Murat; Yaran, Şenel; Hayırlı, Cem; Dolma, Arif

    2013-01-01

    Bu çalışmada, yarı iletken bir gürültü kaynağının “excess noise source” (ENR) değerini izlenebilir şekilde ölçmek için bir toplam güç radyometre kurulmuştur. Oldukça geniş olarak kabul edilen 50 MHz – 26,5 GHz frekans aralığında, gürültü kaynağını tek seferde ölçebilen bu sistemin testi, nominal 15 dB ENR değerine sahip standart gürültü kaynakları kullanılarak yapılmıştır. Geliştirilen toplam güç radyometre kullanılarak, değeri bilinen bir gürültü kaynağının hesaplanan ENR değerleri ile gerçe...

  12. Cold test of cylindrical open resonator for 42 GHz, 200 kW gyrotron

    Vivek Yadav; Sudeep Sharan; Hasina Khatun; Nitin Kumar; M K Alaria; B Jha; S C Deorani; A K Sinha; P K Jain

    2013-12-01

    This paper presents experimental results for cold testing of a gyrotron open resonator. Experiments were carried out to measure resonant frequency and their particular quality factor for TE mode at the frequency 42 GHz. The perturbation technique was used to determine the axial, radial and azimuthal electric field profile for identification of TE031 mode at operating frequency 42 GHz. The good agreement between experimental results and theoretical studies was found. The results verify the design and fabrication of the specific gyrotron cavity.

  13. A 250 GHz gyrotron with a 3 GHz tuning bandwidth for dynamic nuclear polarization.

    Barnes, Alexander B; Nanni, Emilio A; Herzfeld, Judith; Griffin, Robert G; Temkin, Richard J

    2012-08-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementing a long (23 mm) interaction cavity that can excite higher order axial modes by changing either the magnetic field of the gyrotron or the cathode potential. This interaction cavity excites the rotating TE(₅,₂,q) mode, and an internal mode converter outputs a high-quality microwave beam with >94% Gaussian content. The gyrotron was integrated into a DNP spectrometer, resulting in a measured DNP enhancement of 54 on the membrane protein bacteriorhodopsin. PMID:22743211

  14. A 250 GHz gyrotron with a 3 GHz tuning bandwidth for dynamic nuclear polarization

    Barnes, Alexander B.; Nanni, Emilio A.; Herzfeld, Judith; Griffin, Robert G.; Temkin, Richard J.

    2012-08-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementing a long (23 mm) interaction cavity that can excite higher order axial modes by changing either the magnetic field of the gyrotron or the cathode potential. This interaction cavity excites the rotating TE5,2,q mode, and an internal mode converter outputs a high-quality microwave beam with >94% Gaussian content. The gyrotron was integrated into a DNP spectrometer, resulting in a measured DNP enhancement of 54 on the membrane protein bacteriorhodopsin.

  15. Noise in waveguide between 18 GHz and 26.5 GHz

    Allal, D.

    2016-01-01

    This report summarises the results of the Key Comparison CCEM.RF-K22.W on noise temperature, performed between October 2007 and February 2011. In this comparison, the available noise temperature of three noise sources was determined by six National Metrology Institutes (NMIs) in the frequency range from 18 GHz to 26.5 GHz. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  16. A quasioptical resonant-tunneling-diode oscillator operating above 200 GHz

    Brown, E.R.; Parker, C.D.; Calawa, A.R.; Manfra, M.J.; Molvar, K.M. (Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.)

    1993-08-01

    A quasioptical resonant-tunneling-diode oscillator is demonstrated at frequencies above 200 GHz. The oscillator is stabilized by a semiconfocal open cavity. The maximum output power and the linewidth are approximately 50 [mu]W and 20 kHz, respectively, at a fundamental frequency of 210 GHz. By varying the cavity length, the oscillator frequency can be adjusted over a 0.4 GHz range in a repetitive manner. This behavior is explained by analogy with laser oscillators. The quasioptical RTD oscillator is well suited as a local oscillator for low-power radiometric mixers.

  17. Solid-State Power Amplifier For 61.5 GHz

    Powers, Michael K.; Mcclymonds, James; Vye, David; Arthur, Thomas

    1992-01-01

    Power amplifiers based on impact-avalanche-transit-time (IMPATT) diodes developed for operation in communication systems at frequencies near 60 GHz. Built in seven modular stages, power transferred through sections of waveguide and isolator/circulator assemblies. Intended as replacements for bulkier and heavier traveling-wave-tube amplifiers.

  18. First harmonic injection locking of 24-GHz-oscillators

    M. R. Kühn

    2003-01-01

    Full Text Available An increasing number of applications is proposed for the 24 GHz ISM-band, like automotive radar systems and short-range communication links. These applications demand for oscillators providing moderate output power of a few mW and moderate frequency stability of about 0.5%. The maximum oscillation frequency of low-cost off-theshelf transistors is too low for stable operation of a fundamental 24GHz oscillator. Thus, we designed a 24 GHz first harmonic oscillator, where the power generated at the fundamental frequency (12 GHz is reflected resulting in effective generation of output power at the first harmonic. We measured a radiated power from an integrated planar antenna of more than 1mW. Though this oscillator provides superior frequency stability compared to fundamental oscillators, for some applications additional stabilization is required. As a low-cost measure, injection locking can be used to phase lock oscillators that provide sufficient stability in free running mode. Due to our harmonic oscillator concept injection locking has to be achieved at the first harmonic, since only the antenna is accessible for signal injection. We designed, fabricated and characterized a harmonic oscillator using the antenna as a port for injection locking. The locking range was measured versus various parameters. In addition, phase-noise improvement was investigated. A theoretical approach for the mechanism of first harmonic injection locking is presented.

  19. A high efficiency, high power 100 GHz gyrotron

    Gyrotrons, operating at 28 GHz, 35 GHz and 60 GHz are currently producing 100-200 KW, pulsed and CW, for electron cyclotron heating experiments in magnetically-confined gaseous fusion machines. Recently, considerable interest has been expressed towards the development of a 100 GHz, 1.0 MW CW gyrotron for increasing the electron temperature above that achieved with the lower frequency, lower power devices listed above. Toward this goal, Hughes Aircraft Company has developed a 100 GHz, 0.5 MW gyrotron operating at low duty at 30 msec pulse widths. This device employs a single anode magnetron injection gun operating at a cathode voltage of 90 kV at 14A cathode current. Control of the electron beam is by cathode pulsing or CW. RF control is accomplished by low-level cathode magnetic field modulation. Computations show that velocity spread, both perpendicular and parallel, is considerable lower, rotational energy is higher and voltage gradients are significantly lower than for a comparable double anode magnetron injection gun, typically employed on lower frequency gyrotrons

  20. Highly linear and transparent 3-18 GHz optical microwave link

    Nielsen, Torben Nørskov; Gliese, Ulrik Bo; Christensen, T.;

    1994-01-01

    A highly linear optical microwave link transmitter based on heterodyne phase-locked DFB lasers is presented. The transmitter is transparent for FM and PM input signals with carrier frequencies ranging from 3-18 GHz. Distortion-free transmission of a 7.6 GHz FM PAL video signal over 25 km of optical...

  1. High sensitivity broadband 360GHz passive receiver for TeraSCREEN

    Wang, Hui; Oldfield, Matthew; Maestrojuán, Itziar; Platt, Duncan; Brewster, Nick; Viegas, Colin; Alderman, Byron; Ellison, Brian N.

    2016-05-01

    TeraSCREEN is an EU FP7 Security project aimed at developing a combined active, with frequency channel centered at 360 GHz, and passive, with frequency channels centered at 94, 220 and 360 GHz, imaging system for border controls in airport and commercial ferry ports. The system will include automatic threat detection and classification and has been designed with a strong focus on the ethical, legal and practical aspects of operating in these environments and with the potential threats in mind. Furthermore, both the passive and active systems are based on array receivers with the active system consisting of a 16 element MIMO FMCW radar centered at 360 GHz with a bandwidth of 30 GHz utilizing a custom made direct digital synthesizer. The 16 element passive receiver system at 360 GHz uses commercial Gunn diode oscillators at 90 GHz followed by custom made 90 to 180 GHz frequency doublers supplying the local oscillator for 360 GHz sub-harmonic mixers. This paper describes the development of the passive antenna module, local oscillator chain, frequency mixers and detectors used in the passive receiver array of this system. The complete passive receiver chain is characterized in this paper.

  2. Single dish performance of KVN 21-m radio telescopes:Simultaneous observations at 22 and 43 GHz

    Lee, Sang-Sung; Oh, Chung Sik; Han, Seog-Tae; Je, Do-Heung; Kim, Kee-Tae; Wi, Seog-Oh; Cho, Se-Hyung; Sohn, Bong Won; Kim, Jaeheon; Lee, Jeewon; Oh, Se-Jin; Song, Min-Gyu; Kang, Jiman; Jung, Moon-Hee; Lee, Jeong Ae; Oh, Junghwan; Bae, Jae-Han; Yun, So-Young; Lee, Jung-Won; Kim, Bong Gyu; Chung, Hyunsoo; Roh, Duk-Gyoo; Lee, Chang Hoon; Kim, Hyun Goo; Kim, Hyo Ryoung; Yeom, Jae-Hwan; Kurayama, Tomoharu; Jung, Taehyun; Park, Pulun; Kim, Min Joong; Yoon, Dong-Hwan; Kim, Won-Ju

    2011-01-01

    We report simultaneous multi-frequency observing performance at 22 and 43 GHz of the 21-m shaped-Cassegrain radio telescopes of the Korean VLBI Network (KVN). KVN is the first millimeter-dedicated VLBI network in Korea having a maximum baseline length of 480 km. It currently operates at 22 and 43 GHz and planed to operate in four frequency bands, 22, 43, 86, and 129 GHz. The unique quasioptics of KVN enable simultaneous multi-frequency observations based on efficient beam filtering and accuarate antenna-beam alignment at 22 and 43 GHz. We found that the offset of the beams is within 20 degrees.

  3. Flaring Activity of Sgr A* at 43 and 22 GHz: Evidence for Expanding Hot Plasma

    Yusef-Zadeh, F; Heinke, C O; Roberts, D; Wardle, M

    2006-01-01

    We have carried out Very Large Array (VLA) continuum observations to study the variability of Sgr A* at 43 GHz ($\\lambda$=7mm) and 22 GHz ($\\lambda$=13mm). A low level of flare activity has been detected with a duration of $\\sim$ 2 hours at these frequencies, showing the peak flare emission at 43 GHz leading the 22 GHz peak flare by $\\sim20$ to 40 minutes. The overall characteristics of the flare emission are interpreted in terms of the van der Laan model by considering the ejection and adiabatically expansion of a uniform, spherical plasma blob due to flare activity. The observed peak of the flare emission with a spectral index $\

  4. Ultra-wideband and 60 GHz communications for biomedical applications

    Yuce, Mehmet R

    2013-01-01

    This book investigates the design of devices, systems, and circuits for medical applications using the two recently established frequency bands: ultra-wideband (3.1-10.6 GHz) and 60 GHz ISM band. These two bands provide the largest bandwidths available for communication technologies and present many attractive opportunities for medical applications. The applications of these bands in healthcare are wireless body area network (WBAN), medical imaging, biomedical sensing, wearable and implantable devices, fast medical device connectivity, video data transmission, and vital signs monitoring. The r

  5. First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

    Asaji, T.; Nakamura, T.; Furuse, M.; Hitobo, T.; Uchida, T.; Muramatsu, M.; Kato, Y.

    2016-02-01

    A new electron cyclotron resonance ion source has been constructed at Oshima College with a 2.45 GHz magnetron microwave source and permanent magnets employed as the main components. In addition, a solid-state power amplifier with a frequency range of 2.5-6.0 GHz was installed to study two-frequency plasma heating. Three solenoid coils were set up for adjusting the axial magnetic fields. Argon plasma generation and ion beam production have been conducted during the first year of operation. Ion current densities in the ECR plasma were measured using a biased disk. For 2.45 and 4.65 GHz two-frequency plasma heating, the ion density was approximately 1.5 times higher than that of 2.45 GHz single-frequency heating.

  6. First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

    Asaji, T., E-mail: asaji@nc-toyama.ac.jp [National Institute of Technology, Toyama College, 13 Hongo, Toyama 939-8630 (Japan); Nakamura, T.; Furuse, M. [National Institute of Technology, Oshima College, 1091-1 Komatsu, Suouoshima, Oshima, Yamaguchi 742-2193 (Japan); Hitobo, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama 930-1305 (Japan); Uchida, T. [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Muramatsu, M. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2016-02-15

    A new electron cyclotron resonance ion source has been constructed at Oshima College with a 2.45 GHz magnetron microwave source and permanent magnets employed as the main components. In addition, a solid-state power amplifier with a frequency range of 2.5–6.0 GHz was installed to study two-frequency plasma heating. Three solenoid coils were set up for adjusting the axial magnetic fields. Argon plasma generation and ion beam production have been conducted during the first year of operation. Ion current densities in the ECR plasma were measured using a biased disk. For 2.45 and 4.65 GHz two-frequency plasma heating, the ion density was approximately 1.5 times higher than that of 2.45 GHz single-frequency heating.

  7. First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

    A new electron cyclotron resonance ion source has been constructed at Oshima College with a 2.45 GHz magnetron microwave source and permanent magnets employed as the main components. In addition, a solid-state power amplifier with a frequency range of 2.5–6.0 GHz was installed to study two-frequency plasma heating. Three solenoid coils were set up for adjusting the axial magnetic fields. Argon plasma generation and ion beam production have been conducted during the first year of operation. Ion current densities in the ECR plasma were measured using a biased disk. For 2.45 and 4.65 GHz two-frequency plasma heating, the ion density was approximately 1.5 times higher than that of 2.45 GHz single-frequency heating

  8. LFI 30 and 44 GHz receivers Back-End Modules

    Artal, E; de la Fuente, M L; Pascual, J P; Mediavilla, A; Martinez-Gonzalez, E; Pradell, L; de Paco, P; Bara, M; Blanco, E; Garcia, E; Davis, R; Kettle, D; Roddis, N; Wilkinson, A; Bersanelli, M; Mennella, A; Tomasi, M; Butler, R C; Cuttaia, F; Mandolesi, N; Stringhetti, L; 10.1088/1748-0221/4/12/T12003

    2010-01-01

    The 30 and 44 GHz Back End Modules (BEM) for the Planck Low Frequency Instrument are broadband receivers (20% relative bandwidth) working at room temperature. The signals coming from the Front End Module are amplified, band pass filtered and finally converted to DC by a detector diode. Each receiver has two identical branches following the differential scheme of the Planck radiometers. The BEM design is based on MMIC Low Noise Amplifiers using GaAs P-HEMT devices, microstrip filters and Schottky diode detectors. Their manufacturing development has included elegant breadboard prototypes and finally qualification and flight model units. Electrical, mechanical and environmental tests were carried out for the characterization and verification of the manufactured BEMs. A description of the 30 and 44 GHz Back End Modules of Planck-LFI radiometers is given, with details of the tests done to determine their electrical and environmental performances. The electrical performances of the 30 and 44 GHz Back End Modules: f...

  9. Development of a 30 GHz Gyroklystron

    DOE requires sources for testing of high gradient accelerator structures. A power of 50 MW is required at K and Ka band. The pulse length must be ∼ 1 microsecond and the pulse repetition frequency at least 100 Hz. At least some applications may require phase stability not offered by a free running oscillator. CCR proposed to build a 50 MW 30 GHz gyrklystron amplifier. This approach would give the required phase stability. The frequency was at the second harmonic of the cycltron frequency and used the TE02 mode. This makes it possible to design a device without an inner conductor, and with a conventional (non-inverted) MIG. This minimizes cost and the risk due to mechanical alignment issues. A detailed design of the gyroklystron was produced. The design was based on simulations of the cavity(ies), electron gun, output coupler and output window. Two designs were produced. One was at the fundamental of the cyclotron frequency. Simulations predicted an output power of 72 MW with an efficiency of 48%. The other was at the second harmonic, producing 37 MW with an efficiency of 37%.

  10. 100 GHz, 1 MW, CW gyrotron study program. Final report

    The results of a study program to investigate the feasibility of various approaches in designing a 100 GHz, 1 MW CW gyrotron are presented. A summary is given of the possible configurations for a high average power, high frequency gyrotron, including an historical survey of experimental results which are relevant to the various approaches. A set of basic scaling considerations which enable qualitative comparisons between particular gyrotron interaction circuits is presented. These calculations are important in understanding the role of various electron beam and circuit parameters in achieving a viable gyrotron design. Following these scaling exercises, a series of design calculations is presented for a possible approach in achieving 100 GHz, 1 MW CW. These calculations include analyses of the electron gun and interaction circuit parts of the gyrotron, and a general analysis of other aspects of a high average power, high frequency gyrotron. Scalability of important aspects of the design to other frequencies is also discussed, as well as key technology issues

  11. The properties of extragalactic radio sources selected at 20 GHz

    Sadler, E M; Ekers, R D; Ekers, J A; Hancock, P J; Jackson, C A; Kesteven, M J; Murphy, T; Phillips, C; Reinfrank, R F; Staveley-Smith, L; Subramanian, R; Walker, M A; Wilson, W E; De Zotti, G; Sadler, Elaine M.; Ricci, Roberto; Ekers, Ronald D.; Hancock, Paul J.; Jackson, Carole A.; Kesteven, Michael J.; Murphy, Tara; Phillips, Chris; Reinfrank, Robert F.; Staveley-Smith, Lister; Subrahmanyan, Ravi; Walker, Mark A.; Wilson, Warwick E.; Zotti, Gianfranco De

    2006-01-01

    We present some first results on the variability, polarization and general properties of a flux-limited sample of radio sources selected in a blind survey at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of sky. Sources with flux densities above 100 mJy in the ATCA 20 GHz Pilot Survey were observed at up to three epochs during 2002-4, including near-simultaneous flux measurements at 4.8, 8.6 and 18 GHz in late 2003. Of the 173 sources in our sample, 65% are identified with candidate QSOs, BL Lac objects or blazars, 20% with galaxies and 15% with faint (b > 22 mag) optical objects or blank fields. On a 1-2 year timescale, the general level of variability at 20 GHz appears to be low. For the 108 sources with good-quality measurements in both 2003 and 2004, the median variability index at 20 GHz over this one-year timescale was 6.9% and only five sources varied by more than 30% in flux density. Most sources in our sample show low levels of linear polarizat...

  12. IR-correlated 31 GHz radio emission from Orion East

    Dickinson, C; Davies, R D; Allison, J R; Bustos, R; Cleary, K; Davis, R J; Jones, M E; Pearson, T J; Readhead, A C S; Reeves, R; Taylor, A C; Tibbs, C T; Watson, R A

    2010-01-01

    Lynds dark cloud LDN1622 represents one of the best examples of anomalous dust emission, possibly originating from small spinning dust grains. We present Cosmic Background Imager (CBI) 31 GHz data of LDN1621, a diffuse dark cloud to the north of LDN1622 in a region known as Orion East. A broken ring with diameter g\\approx 20 arcmin of diffuse emission is detected at 31 GHz, at \\approx 20-30 mJy beam$^{-1}$ with an angular resolution of \\approx 5 arcmin. The ring-like structure is highly correlated with Far Infra-Red emission at $12-100 \\mu$m with correlation coefficients of r \\approx 0.7-0.8, significant at $\\sim10\\sigma$. Multi-frequency data are used to place constraints on other components of emission that could be contributing to the 31 GHz flux. An analysis of the GB6 survey maps at 4.85 GHz yields a $3\\sigma$ upper limit on free-free emission of 7.2 mJy beam$^{-1}$ ($\\la 30 per cent of the observed flux) at the CBI resolution. The bulk of the 31 GHz flux therefore appears to be mostly due to dust radiat...

  13. Frequency selective lens antenna

    Thornton, J.; Haines, P.

    2007-01-01

    A variant of the hemispherical microwave lens antenna is reported where the ground plane region is modified through use of a frequency selective surface. This allows discrimination of frequencies by two closely spaced primary feeds. A scale model is reported operating at 12 and 30 GHz.

  14. A 60 GHz Planar Diplexer Based on Substrate Integrated Waveguide Technology

    Nikolaos Athanasopoulos; Dimitrios Makris; Konstantinos Voudouris

    2013-01-01

    This paper presents a millimeter-wave, 60 GHz frequency band planar diplexer based on substrate integrated waveguide (SIW) technology. Diplexer consists of a pair of 5th-order SIW bandpass channel filters with center frequencies at 59.8 GHz and 62.2 GHz providing 1.67% and 1.6% relative bandwidths, respectively. SIW-to-microstrip transitions at diplexer ports enable integration in a millimeter-wave transceiver front end. Measurements are in good agreement with electromagnetic simulation, repo...

  15. MMIC DHBT Common-Base Amplifier for 172 GHz

    Paidi, Vamsi; Griffith, Zack; Wei, Yun; Dahlstrom, Mttias; Urteaga, Miguel; Rodwell, Mark; Samoska, Lorene; Fung, King Man; Schlecht, Erich

    2006-01-01

    Figure 1 shows a single-stage monolithic microwave integrated circuit (MMIC) power amplifier in which the gain element is a double-heterojunction bipolar transistor (DHBT) connected in common-base configuration. This amplifier, which has been demonstrated to function well at a frequency of 172 GHz, is part of a continuing effort to develop compact, efficient amplifiers for scientific instrumentation, wide-band communication systems, and radar systems that will operate at frequencies up to and beyond 180 GHz. The transistor is fabricated from a layered structure formed by molecular beam epitaxy in the InP/InGaAs material system. A highly doped InGaAs base layer and a collector layer are fabricated from the layered structure in a triple mesa process. The transistor includes two separate emitter fingers, each having dimensions of 0.8 by 12 m. The common-base configuration was chosen for its high maximum stable gain in the frequency band of interest. The input-matching network is designed for high bandwidth. The output of the transistor is matched to a load line for maximum saturated output power under large-signal conditions, rather than being matched for maximum gain under small-signal conditions. In a test at a frequency of 172 GHz, the amplifier was found to generate an output power of 7.5 mW, with approximately 5 dB of large-signal gain (see Figure 2). Moreover, the amplifier exhibited a peak small-signal gain of 7 dB at a frequency of 176 GHz. This performance of this MMIC single-stage amplifier containing only a single transistor represents a significant advance in the state of the art, in that it rivals the 170-GHz performance of a prior MMIC three-stage, four-transistor amplifier. [The prior amplifier was reported in "MMIC HEMT Power Amplifier for 140 to 170 GHz" (NPO-30127), NASA Tech Briefs, Vol. 27, No. 11 (November 2003), page 49.] This amplifier is the first heterojunction- bipolar-transistor (HBT) amplifier built for medium power operation in this

  16. Dynamic spectra of pulsar scintillations at frequencies near 0.34, 0.41, 0.63, 1.4, 1.7, 3.2 and 5.0 GHz

    Examples are given of the dynamic spectra of the interstellar scintillations of radiation received from the pulsars PSR 0628-28, 0833-45, 0834+06, 0950+08, 1451-68, 1642-03, 1749-28, 1919+21 and 1929+10. The auto-covariance of the intensity is calculated as a function of separation in time and frequency to yield scattering parameters for eight of these pulsars and for PSR 1933+16. For PSR 0833-45 the details of the shapes of the auto-covariance functions, and the scaling with frequency, are compared with theory. For two pulsars, PSR 0628-28 and PSR 0834+06, systematic patterns of drifting bands were found in the dynamic spectra. The occurrence of such spectra implies that on these occasions the radiation reached the Earth predominantly from a few directions only. The implications of this result for the distribution of irregularity scales in the interstellar medium are discussed. (author)

  17. Integrated 60GHz RF beamforming in CMOS

    Yu, Yikun; van Roermund, Arthur H M

    2011-01-01

    ""Integrated 60GHz RF Beamforming in CMOS"" describes new concepts and design techniques that can be used for 60GHz phased array systems. First, general trends and challenges in low-cost high data-rate 60GHz wireless system are studied, and the phased array technique is introduced to improve the system performance. Second, the system requirements of phase shifters are analyzed, and different phased array architectures are compared. Third, the design and implementation of 60GHz passive and active phase shifters in a CMOS technology are presented. Fourth, the integration of 60GHz phase shifters

  18. Miniature microwave plasma antenna at 2.45 GHz

    Vachkov, Vasil; Kiss'ovski, Zhivko

    2015-12-01

    New unique miniature plasma antenna driven by a one microwave signal at frequency of 2.45 GHz is constructed and tested. The length of the antenna (l = 16 mm) is much shorter than the free space wavelength of the signal. The parameters of the plasma column (n = 2.6±0.4×1018 m-3, Te = 3.1±0.2 eV) are obtained from argon emission spectrum by applying the line ratio method. The simulations of this monopole antenna reveal that in the standing wave regime the plasma antenna is effective transmitter at a frequency of 2.45 GHz. The results we obtained show that the shape of the radiation pattern of the plasma antenna depends on the plasma density, the exciter and the distance above the grounded plane.

  19. Analisis Kelayakan Implementasi Teknologi LTE 1.8 GHz Bagi Operator Seluler di Indonesia [Feasibility Analysis of LTE 1.8 GHz for Mobile Operators in Indonesia

    Sri Ariyanti

    2015-06-01

    Full Text Available Peningkatan kebutuhan layanan data mendorong operator telekomunikasi berusaha mengimplementasikan jaringan akses broadband yang lebih handal.  Teknologi LTE merupakan salah satu teknologi dengan kecepatan mencapai tiga kali dibanding teknologi HSDPA, sehingga diharapkan dapat memenuhi kebutuhan pelanggan data mobile. Refarming frekuensi 1.8 GHz  untuk penerapan teknologi LTE memberikan efisiensi karena tidak perlu membayar BHP lagi untuk menyewa frekuensi baru. Teknologi 2G GSM selama ini juga semakin ditinggalkan, masyarakat di daerah perkotaan cenderung lebih banyak menggunakan layanan data.  Sebelum diterapkannya teknologi LTE pada frekuensi 1.8 GHz perlu adanya kajian untuk mengetahui kelayakan teknologi LTE pada frekuensi 1.8 GHz. Penelitian ini bertujuan untuk melakukan cost-benefit analysis implementasi LTE pada frekuensi 1.8 GHz.  Metode penelitian menggunakan pendekatan kualitataif yang didukung dengan data kuantitatif.  Hasil penelitian menunjukkan bahwa minimal bandiwdth yang diperlukan agar implementasi LTE layak digunakan adalah 15 MHz.  Meskipun tanpa Global Frequency Returning, penggunaan bandwidth 10 MHz tidak layak digunakan untuk implementasi LTE.      *****The incresing of data demand drives mobile operators to implement more reliable broadband access network. LTE technology has downlink peak rate up to three times than HSDPA,  hence it may fulfill the mobile data user requirement. Frequency 1.8 GHz refarming can be implemented to provide efficiency because They do not need to pay licence fee for leasing new frequency. GSM technology will be abandoned since it is not growing anymore. Besides that, dense urban users tend to use data mobile.  Before implementing LTE technology  on 1.8 GHz frequency, It is necessary to analysis the feasibility such technology. This research used qualitative method supported by quantitative  approach.  The result of this research showed that minimum bandwidth to implement 1.8 GHz LTE

  20. A Frequency-Reconfigurable Monopole Antenna with Switchable Stubbed Ground Structure

    Liu, X. L.; X. L. Yang; F.L.Kong

    2015-01-01

    A frequency-reconfigurable coplanar-waveguide (CPW) fed monopole antenna using switchable stubbed ground structure is presented. Four PIN diodes are employed in the stubs stretching from the ground to make the antenna reconfigurable in three operating modes: a single-band mode (2.4-2.9 GHz), a dual-band mode (2.4-2.9 GHz/5.09-5.47 GHz) and a triple-band mode (3.7-4.26 GHz/5.3-6.3 GHz/8.0-8.8 GHz). The monopole antenna is resonating at 2.4 GHz, while the stubs produce other operating frequency...

  1. Characterization of a gyrotron cavity at 10 GHz

    Experiments have been conducted to characterize a gyrotron cavity designed to operate in the Te 021 mode at 10 GHz. Small holes were introduced into the cavity to couple in and detect the probing power. Evaluation of the loaded Q factor is based on bandwidth measurements whereas standing-wave electric field profile is determined by using perturbation techniques. Good agreement between measured and predicted values of resonant frequencies and Q factors for several fundamental TE modes is found. (author)

  2. 10 GHz femtosecond pulse interleaver in planar waveguide technology

    Sander, M. Y.; Frolov, S.; Shmulovich, J.; Ippen, E. P.; Kärtner, F. X.

    2012-01-01

    Coherent pulse interleaving implemented in planar waveguide technology is presented as a compact and robust solution to generate high repetition rate frequency combs. We demonstrate a 10 GHz pulse train from an Er-doped femtosecond fiber laser that is coupled into waveguide interleavers and multiplied in repetition rate by a factor of 16. With thermal tuning of the chip elements, we achieve optical and RF sidemode suppression levels of at least -30 dB.

  3. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

    2009-01-01

    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  4. High power 303 GHz gyrotron for CTS in LHD

    Yamaguchi, Y.; Kasa, J.; Saito, T.; Tatematsu, Y.; Kotera, M.; Kubo, S.; Shimozuma, T.; Tanaka, K.; Nishiura, M.

    2015-10-01

    A high-power pulsed gyrotron is under development for 300 GHz-band collective Thomson scattering (CTS) diagnostics in the Large Helical Device (LHD). High-density plasmas in the LHD require a probe wave with power exceeding 100 kW in the sub-terahertz region to obtain sufficient signal intensity and large scattering angles. At the same time, the frequency bandwidth should be less than several tens of megahertz to protect the CTS receiver using a notch filter against stray radiations. Moreover, duty cycles of ~ 10% are desired for the time domain analysis of the CTS spectrum. At present, a 77 GHz gyrotron for electron cyclotron heating is used as a CTS wave source in the LHD. However, the use of such a low-frequency wave suffers from refraction, cutoff and absorption at the electron cyclotron resonance layer. Additionally, the signal detection is severely affected by background noise from electron cyclotron emission. To resolve those problems, high-power gyrotrons in the 300 GHz range have been developed. In this frequency range, avoiding mode competition is critical to realizing high-power and stable oscillation. A moderately over-moded cavity was investigated to isolate a desired mode from neighbouring modes. After successful tests with a prototype tube, the practical one was constructed with a cavity for TE22,2 operation mode, a triode electron gun forming intense laminar electron beams, and an internal mode convertor. We have experimentally confirmed single mode oscillation of the TE22,2 mode at the frequency of 303.3 GHz. The spectrum peak is sufficiently narrow. The output power of 290 kW has been obtained at the moment.

  5. High power 303 GHz gyrotron for CTS in LHD

    A high-power pulsed gyrotron is under development for 300 GHz-band collective Thomson scattering (CTS) diagnostics in the Large Helical Device (LHD). High-density plasmas in the LHD require a probe wave with power exceeding 100 kW in the sub-terahertz region to obtain sufficient signal intensity and large scattering angles. At the same time, the frequency bandwidth should be less than several tens of megahertz to protect the CTS receiver using a notch filter against stray radiations. Moreover, duty cycles of ∼ 10% are desired for the time domain analysis of the CTS spectrum. At present, a 77 GHz gyrotron for electron cyclotron heating is used as a CTS wave source in the LHD. However, the use of such a low-frequency wave suffers from refraction, cutoff and absorption at the electron cyclotron resonance layer. Additionally, the signal detection is severely affected by background noise from electron cyclotron emission. To resolve those problems, high-power gyrotrons in the 300 GHz range have been developed. In this frequency range, avoiding mode competition is critical to realizing high-power and stable oscillation. A moderately over-moded cavity was investigated to isolate a desired mode from neighbouring modes. After successful tests with a prototype tube, the practical one was constructed with a cavity for TE22,2 operation mode, a triode electron gun forming intense laminar electron beams, and an internal mode convertor. We have experimentally confirmed single mode oscillation of the TE22,2 mode at the frequency of 303.3 GHz. The spectrum peak is sufficiently narrow. The output power of 290 kW has been obtained at the moment

  6. VLBI observations of 3C273 at 22 GHz and 43 GHz ; 2, test of Synchrotron Self-Compton process

    Mantovani, F; McHardy, I M; Valerio, C

    1999-01-01

    The VLBI observations at 22 GHz and 43 GHz of the quasar 3C273 obtained during a multi-frequency campaign in late 1992 in the radio, millimetre and X-ray bands allow us to derive the components' angular sizes, their peak fluxes and turnover frequencies. Lower limits to the Doppler factors have been derived by comparing the observed X-ray fluxes with those predicted by the Synchrotron Self-Compton model. Independent estimates of the Doppler factors were obtained through the assumption of the energy equipartition between the particles and the magnetic field. Of the five components used to model the first two milli-arcseconds of the jet, apart from the core, two components are in equipartition and the remaining two, at larger distances from the core, have large Doppler factors and are mainly responsible for the X-ray emission due to the Synchrotron Self-Compton process.

  7. The properties of powerful radio sources at 90 GHz

    Hardcastle, M J

    2008-01-01

    We have observed a small sample of powerful double radio sources (radio galaxies and quasars) at frequencies around 90 GHz with the BIMA millimetre array, with the intention of constraining the resolved high-frequency spectra of radio galaxies. When combined with other sources we have previously observed and with data from the BIMA archive, these observations allow us for the first time to make general statements about the high-frequency behaviour of compact components of radio galaxies -- cores, jets and hotspots. We find that cores in our sample remain flat-spectrum up to 90 GHz; jets in some of our targets are detected at 90 GHz for the first time in our new observations; and hotspots are found to be almost universal, but show a wide range of spectral properties. Emission from the extended lobes of radio galaxies is detected in a few cases and shows rough consistency with the expectations from standard spectral ageing models, though our ability to probe this in detail is limited by the sensitivity of BIMA....

  8. Optimization of a 115 GHz waveguide mixer based on an HTS Josephson junction

    A waveguide mixer based on a Josephson junction made from a high-temperature superconductor (HTS) has been analysed at frequencies of 90 GHz and 115 GHz. The mixer consisted of a single-grain-boundary bicrystal junction which was integrated with a bow-tie antenna and a microstrip filter structure fabricated on an MgO substrate. Two different designs of mixer block were tested. Using the first design the best noise performance was measured at a local oscillator (LO) frequency of about 90 GHz. At the projected LO frequency of 115 GHz significant deterioration of performance was observed. A computer simulation of the mixer chip and substrate channel structure was performed using the 3D simulation program HFSS. Sufficient RF signal rejection by the filter structure was confirmed at 90 GHz. After a simulation cycle at 115 GHz the substrate channel in the mixer block was modified. Using this second design we measured a double-sideband mixer noise temperature of 1090 K at 10 K operating temperature which is the best performance of an HTS Josephson mixer to date obtained at this frequency and temperature. (author)

  9. Experimental results of superimposing 9.9 GHz extraordinary mode microwaves on 2.45 GHz ECRIS plasma

    Efficient production of multicharged ions has been investigated on the tandem-type ECRIS in Osaka University. According to the consideration of the accessibility conditions of microwaves to resonance and cutoff regions, it was suggested that the upper hybrid resonance (UHR) heating contributed to enhancement of ion beam intensity. In order to enhance multicharged ion beams efficiently, injecting higher frequency microwave with extraordinary (X-mode) toward UHR region has been tried. In this study, 2.45 GHz frequency microwaves are used for conventional ECR discharge, and 9.9 GHz frequency microwaves with X-mode are superimposed for UHR heating. The effects of additive microwave injection are investigated experimentally in terms of plasma parameters and electron energy distribution function (EEDF) measured by Langmuir probe and ion beam current. As the results show, it is confirmed that the electrons in the high energy region are affected by 9.9 GHz X-mode microwave injection from the detailed analysis of EEDF

  10. Experimental results of superimposing 9.9 GHz extraordinary mode microwaves on 2.45 GHz ECRIS plasma

    Nishiokada, Takuya, E-mail: nishiokada@nf.eie.eng.osaka-u.ac.jp; Nagaya, Tomoki; Hagino, Shogo; Otsuka, Takuro; Sato, Fuminobu; Kato, Yushi [Division of Electrical, Electronic, and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Muramatsu, Masayuki; Kitagawa, Atsushi [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-855 (Japan)

    2016-02-15

    Efficient production of multicharged ions has been investigated on the tandem-type ECRIS in Osaka University. According to the consideration of the accessibility conditions of microwaves to resonance and cutoff regions, it was suggested that the upper hybrid resonance (UHR) heating contributed to enhancement of ion beam intensity. In order to enhance multicharged ion beams efficiently, injecting higher frequency microwave with extraordinary (X-mode) toward UHR region has been tried. In this study, 2.45 GHz frequency microwaves are used for conventional ECR discharge, and 9.9 GHz frequency microwaves with X-mode are superimposed for UHR heating. The effects of additive microwave injection are investigated experimentally in terms of plasma parameters and electron energy distribution function (EEDF) measured by Langmuir probe and ion beam current. As the results show, it is confirmed that the electrons in the high energy region are affected by 9.9 GHz X-mode microwave injection from the detailed analysis of EEDF.

  11. 75 FR 45058 - Operation of Wireless Communications Services in the 2.3 GHz Band; Establishment of Rules and...

    2010-08-02

    ... Licensees. The Wireless Communication Service in the 2305- 2360 MHz (2.3 GHz) frequency band has flexible...- 8610; FCC 10-82] Operation of Wireless Communications Services in the 2.3 GHz Band; Establishment of... amends its rules to enable the deployment of mobile broadband services in the Wireless...

  12. The Australia Telescope 20GHz (AT20G) Survey: analysis of the extragalactic source sample

    Massardi, Marcella; end_of_the_skype_highlighting, Tara Murphy begin_of_the_skype_highlighting end_of_the_skype_highlighting begin_of_the_skype_highlighting; Mahony, Elizabeth; Hancock, Paul J; Chhetri, Rajan; De Zotti, Gianfranco; Sadler, Elaine M; Burke-Spolaor, Sarah; Calabretta, Mark; Edwards, Philip G; Ekers, Jennifer A; Jackson, Carole A; Kesteven, Michael J; Newton-McGee, Katherine; Phillips, Chris; Ricci, Roberto; Roberts, Paul; Sault, Robert J; Staveley-Smith, Lister; Subrahmanyan, Ravi; Walker, Mark A; Wilson, Warwick E

    2010-01-01

    The Australia Telescope 20 GHz (AT20G) survey is a blind survey of the whole Southern sky at 20 GHz with follow-up observations at 4.8, 8.6, and 20 GHz carried out with the Australia Telescope Compact Array (ATCA). In this paper we present an analysis of radio spectral properties in total intensity and polarisation, sizes, optical identifications, and redshifts of the sample of the 5808 extragalactic sources in the survey catalogue of confirmed sources over the whole Southern sky excluding the strip at Galactic latitude |b|500mJy, to 60% for S<100mJy. There is also a clear spectral steepening at higher frequencies with the median spectral index decreasing from -0.16 between 4.8 and 8.6GHz to -0.28 between 8.6 and 20GHz. Simultaneous observations in polarisation are available for all the sources at all the frequencies. 768 sources have a good quality detection of polarised flux density at 20GHz; 467 of them were also detected in polarisation at 4.8 and/or at 8.6GHz so that it has been possible to compare th...

  13. The 4.8 GHz LHC Schottky pick-up system

    The LHC Schottky observation system is based on traveling wave type high sensitivity pickup structures operating at 4.8 GHz. The choice of the structure and operating frequency is driven by the demanding LHC impedance requirements, where very low impedance is required below 2 GHz, and good sensitivity at the selected band at 4.8 GHz. A sophisticated filtering and triple down -mixing signal processing chain has been designed and implemented in order to achieve the specified 100 dB instantaneous dynamic range without range switching. Detailed design aspects for the complete systems and test results without beam are presented and discussed

  14. A 3 to 6 GHz microwave/photonic transceiver for phased-array interconnects

    Ackerman, Edward; Wanuga, Stephen; Candela, Karen; Scotti, Ronald E.; MacDonald, V. W.; Gates, John V.

    1992-04-01

    The general design and operation of a microwave/photonic transceiver operating in the range 3-6 GHz are presented. The transceiver consists of drop-in submodules with optical fiber pigtails mounted on a brass carrier measuring less than 1 x 1 x 0.1 inch along with MMIC amplifiers and an alumina motherboard. Minimum 3 to 6 GHz return losses of 6 dB have been measured for both the microwave input and the microwave output of the module; the insertion loss is between 19 and 20 dB at most frequencies in the 3-6 GHz band.

  15. 80 GHz waveform generated by the optical Fourier synthesis of four spectral sidebands

    Fatome, Julien; Hammani, Kamal; Kibler, Bertrand; Finot, Christophe

    2016-01-01

    Using the linear phase shaping of a simple four-line optical frequency comb, we experimentally demonstrate the generation of various optical waveforms such as parabolic, triangular or flat-top pulse trains at a repetition rate of 80 GHz. The initial 80 GHz comb is obtained through the nonlinear spectral broadening of a 40 GHz carrier-suppressed sinusoidal beating in a highly nonlinear fiber. Proof-of-principle experiments are reported for two distinct configurations of the waveform generated: continuous trains and bunches of shaped pulses.

  16. High performance oscillator with 2-mW output power at 300 GHz

    Material structures and device structures of a 100-GHz InP based transferred-electron device are designed in this paper. In order to successfully fabricate the Gunn devices operating at 100 GHz, the InP substrate was entirely removed by mechanical thinning and wet etching. The Gunn device was connected to a tripler link and a high RF (radio frequency) output with power of 2 mW working at 300 GHz was obtained, which is high enough for applications in current military electronic systems. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. High-Capacity 60 GHz and 75–110 GHz Band Links Employing All-Optical OFDM Generation and Digital Coherent Detection

    Caballero Jambrina, Antonio; Zibar, Darko; Sambaraju, Rakesh; Marti, Javier; Tafur Monroy, Idelfonso

    2012-01-01

    The performance of wireless signal generation and detection at millimeter-wave frequencies using baseband optical means is analyzed and experimentally demonstrated. Multigigabit wireless signal generation is achieved based on all-optical orthogonal frequency division multiplexing (OFDM) and photo...... scalability and bit-rate transparency of our proposed approach, we experimentally demonstrated generation and detection in the 60 GHz and 75–110 GHz band of an all-optical OFDM quadrature phase shift keying, with two and three subcarriers, for a total bit rate over 20 Gb/ s....

  18. Diseño de un amplificador de alta eficiencia clase-E @ 2GHz

    Peña Catalina, Roberto; García García, José Ángel; Chaibi, Mohamed; Amar Touhami, Naima

    2004-01-01

    Class-E power amplifiers have 100% theoretical efficiency, due to switched-mode operation. This concept has traditionally been applied to VHF and UHF frequency ranges. In this paper we propose its application to microwave frequencies, designing and characterizing a class-E power amplifier at 2 GHz based on a HEMT solid state device and microstrip technology.

  19. LFI 30 and 44 GHz receivers Back-End Modules

    Artal, E.; Aja, B.; de la Fuente, M. L.; Pascual, J. P.; Mediavilla, A.; Martinez-Gonzalez, E.; Pradell, L.; de Paco, P.; Bara, M.; Blanco, E.; García, E.; Davis, R.; Kettle, D.; Roddis, N.; Wilkinson, A.; Bersanelli, M.; Mennella, A.; Tomasi, M.; Butler, R. C.; Cuttaia, F.; Mandolesi, N.; Stringhetti, L.

    2009-12-01

    The 30 and 44 GHz Back End Modules (BEM) for the Planck Low Frequency Instrument are broadband receivers (20% relative bandwidth) working at room temperature. The signals coming from the Front End Module are amplified, band pass filtered and finally converted to DC by a detector diode. Each receiver has two identical branches following the differential scheme of the Planck radiometers. The BEM design is based on MMIC Low Noise Amplifiers using GaAs P-HEMT devices, microstrip filters and Schottky diode detectors. Their manufacturing development has included elegant breadboard prototypes and finally qualification and flight model units. Electrical, mechanical and environmental tests were carried out for the characterization and verification of the manufactured BEMs. A description of the 30 and 44 GHz Back End Modules of Planck-LFI radiometers is given, with details of the tests done to determine their electrical and environmental performances. The electrical performances of the 30 and 44 GHz Back End Modules: frequency response, effective bandwidth, equivalent noise temperature, 1/f noise and linearity are presented.

  20. A 12 GHZ RF Power source for the CLIC study

    Peauger, F; Curt, S; Doebert, S; McMonagle, G; Rossat, G; Schirm, KM; Syratchev, I; Timeo, L; Kuzikhov, S; Vikharev, AA; Haase, A; Sprehn, D; Jensen, A; Jongewaard, EN; Nantista, CD; Vlieks, A

    2010-01-01

    The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for CLIC accelerating structure testing. A design and fabrication contract for five klystrons at that frequency has been signed by different parties with SLAC. France (IRFU, CEA Saclay) is contributing a solid state modulator purchased in industry and specific 12 GHz RF network components to the CLIC study. RF pulses over 120 MW peak at 230 ns length will be obtained by using a novel SLED-I type pulse compression scheme designed and fabricated by IAP, Nizhny Novgorod, Russia. The X-band power test stand is being installed in the CLIC Test Facility CTF3 for independent structure and component testing in a bunker, but allowing, in a later stage, for powering RF components in the CTF3 beam lines. The design of the facility, results from commissioning of the RF power source and the expected performance of the Test Facility are reported.

  1. Planck 2013 results. VI. High Frequency Instrument data processing

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.;

    2013-01-01

    , and 857 GHz with an angular resolution ranging from 9.07 to 4.06. The detector noise per (effective) beam solid angle is respectively,10, 6 , 12, and 39 µK in the four lowest HFI frequency channels (100-353 GHz) and 13 and 14 kJy sr-1 in the 545 and 857 GHz channels. Relativeto the 143 GHz channel...

  2. Specifics of processing SRS lidar signals in GHz frequency range

    Grishkanich, A. S.; Elizarov, V. V.; Kascheev, S. V.; Zhevlakov, A. P.; Sidorov, I. S.

    2015-12-01

    One of the highly effective methods of operative remote environmental monitoring on land and water surfaces is laser sensing. It knew that the Raman scattering cross section is very small (10-25-10-27), so in some cases radiation back into captivity to the target could be a few tens of photons. For high-speed sensing, speed of processing and ease of use lidar units required for the use of appropriate hardware and software systems used for the decision of tasks of collecting, processing, storing, organizing large amounts of data.

  3. Antennas for 20/30 GHz and beyond

    Chen, C. Harry; Wong, William C.; Hamada, S. Jim

    1989-01-01

    Antennas of 20/30 GHz and higher frequency, due to the small wavelength, offer capabilities for many space applications. With the government-sponsored space programs (such as ACTS) in recent years, the industry has gone through the learning curve of designing and developing high-performance, multi-function antennas in this frequency range. Design and analysis tools (such as the computer modelling used in feedhorn design and reflector surface and thermal distortion analysis) are available. The components/devices (such as BFN's, weight modules, feedhorns and etc.) are space-qualified. The manufacturing procedures (such as reflector surface control) are refined to meet the stringent tolerance accompanying high frequencies. The integration and testing facilities (such as Near-Field range) also advance to facilitate precision assembling and performance verification. These capabilities, essential to the successful design and development of high-frequency spaceborne antennas, shall find more space applications (such as ESGP) than just communications.

  4. Single- and Multiband OFDM Photonic Wireless Links in the 75−110 GHz Band Employing Optical Combs

    Beltrán, M.; Deng, Lei; Pang, Xiaodan; Zhang, Xu; Arlunno, Valeria; Zhao, Ying; Yu, Xianbin; Llorente, R.; Liu, D.; Tafur Monroy, Idelfonso

    2012-01-01

    The photonic generation of electrical orthogonal frequency-division multiplexing (OFDM) modulated wireless signals in the 75−110 GHz band is experimentally demonstrated employing in-phase/quadrature electrooptical modulation and optical heterodyn upconversion. The wireless transmission of 16...

  5. Design of a 50 MW, 34 GHz second harmonic coaxial gyroklystron for advanced accelerators

    At the University of Maryland, the authors have been investigating the feasibility of using gyroklystrons and gyroklystrons as drivers for linear colliders and advanced accelerators for a number of years. The most recent experimental tube achieved a peak power of about 80 MW at 8.57 GHz with 32% efficiency and over 30 dB gain with a three-cavity first harmonic circuit. The current experimental effort is devoted to producing about 100 MW of peak power at 17.14 GHz with a second-harmonic three-cavity tube. Some schemes for advanced linear colliders with center-of-mass energies of 5 TeV or more expect to require higher frequency sources, perhaps near 35 GHz or 91 GHz. A design study at 95 GHz indicated that peak powers near 7 MW were possible. In this design study, they present the simulated operating characteristics of a four cavity 34 GHz second-harmonic gyroklystron tube which is capable of producing about 60 MW of peak power with an efficiency of about 40% and a gain above 50 dB. The electron gun is a single-anode magnetron injection gun. The input cavity is a TE011 cavity which is driven at 17 GHz. The remainder of the cavities are TE021 cavities which interact near the second harmonic of the cyclotron frequency. The gain cavity and the output cavities are at twice the drive frequency, but the penultimate cavity is detuned to enhance efficiency. All cavities are abrupt-transition cavities. Both systems are derived from scaled versions of the 17 GHz tube. In this paper, they present detailed designs and performance predictions for both the electron gun and the microwave circuit

  6. Design of a 50 MW, 34 GHz second harmonic coaxial gyroklystron for advanced accelerators

    Arjona, M.R.; Lawson, W.

    1999-07-01

    At the University of Maryland, the authors have been investigating the feasibility of using gyroklystrons and gyroklystrons as drivers for linear colliders and advanced accelerators for a number of years. The most recent experimental tube achieved a peak power of about 80 MW at 8.57 GHz with 32% efficiency and over 30 dB gain with a three-cavity first harmonic circuit. The current experimental effort is devoted to producing about 100 MW of peak power at 17.14 GHz with a second-harmonic three-cavity tube. Some schemes for advanced linear colliders with center-of-mass energies of 5 TeV or more expect to require higher frequency sources, perhaps near 35 GHz or 91 GHz. A design study at 95 GHz indicated that peak powers near 7 MW were possible. In this design study, they present the simulated operating characteristics of a four cavity 34 GHz second-harmonic gyroklystron tube which is capable of producing about 60 MW of peak power with an efficiency of about 40% and a gain above 50 dB. The electron gun is a single-anode magnetron injection gun. The input cavity is a TE{sub 011} cavity which is driven at 17 GHz. The remainder of the cavities are TE{sub 021} cavities which interact near the second harmonic of the cyclotron frequency. The gain cavity and the output cavities are at twice the drive frequency, but the penultimate cavity is detuned to enhance efficiency. All cavities are abrupt-transition cavities. Both systems are derived from scaled versions of the 17 GHz tube. In this paper, they present detailed designs and performance predictions for both the electron gun and the microwave circuit.

  7. Teleportation of a 3-dimensional GHZ State

    Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei; Song, He-Shan

    2012-05-01

    The process of teleportation of a completely unknown 3-dimensional GHZ state is considered. Three maximally entangled 3-dimensional Bell states function as quantum channel in the scheme. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional GHZ state.

  8. Exploring the faint source population at 15.7 GHz

    Whittam, Imogen H; Green, David A; Jarvis, Matt J

    2016-01-01

    We discuss our current understanding of the nature of the faint, high-frequency radio sky. The Tenth Cambridge (10C) survey at 15.7 GHz is the deepest high-frequency radio survey to date, covering 12 square degrees to a completeness limit of 0.5 mJy, making it the ideal starting point from which to study this population. In this work we have matched the 10C survey to several lower-frequency radio catalogues and a wide range of multi-wavelength data (near- and far-infrared, optical and X-ray). We find a significant increase in the proportion of flat-spectrum sources at flux densities below 1 mJy - the median radio spectral index between 15.7 GHz and 610 MHz changes from 0.75 for flux densities greater than 1.5 mJy to 0.08 for flux densities less than 0.8 mJy. The multi-wavelength analysis shows that the vast majority (> 94 percent) of the 10C sources are radio galaxies; it is therefore likely that these faint, flat spectrum sources are a result of the cores of radio galaxies becoming dominant at high frequenci...

  9. Design of High Gain and Broadband Antennas at 60 GHz for Underground Communications Systems

    Yacouba Coulibaly

    2012-01-01

    Full Text Available A new broadband and high gain dielectric resonator antenna for millimeter wave is presented. The investigated antenna configuration consists of a periodic square ring frequency selective surfaces on a superstrate, an aperture-coupled scheme feed, an intermediate substrate, and a cylindrical dielectric resonator. This antenna is designed to cover the ISM frequency band at 60 GHz (57 GHz–64 GHz. It was numerically designed using CST microwave Studio simulation software package. Another prototype with a plain dielectric superstrate is also studied for comparison purposes. A bandwidth of 13.56% at the centered frequency of 61.34 GHz and a gain of 11 dB over the entire ISM band have been achieved. A maximum gain of 14.26 dB is obtained at 60 GHz. This is an enhancement of 9 dB compared to a single DRA. HFSS is used to validate our antenna designs. Good agreement between the results of the two softwares is obtained. With these performances, these antennas promise to be useful in the design of future wireless underground communication systems operating in the unlicensed 60 GHz frequency band.

  10. Dual channel 115 and 230 GHz SIS receivers in operation at the Owens Valley Radio Observatory

    The Owens Valley Radio Observatory millimeter-wave interferometer array is presently operating with dual channel SIS tunnel junction receivers. The first channel covers the frequency range from 85 to 120 GHz and the second channel covers the frequency range from 200 to 300 GHz. The mixers consist of a corrugated feedhorn, single-stage circular to rectangular waveguide transition, reduced-height waveguide with an SIS junction mounted across the E-plane and a non-contacting backshort. The mixer block has a built-in RF choke for the IF signal path which is designed to present a short circuit to the junction at frequencies above the 2 GHz IF frequency. The small area (<1 μm/sup 2/) PbInAu-native oxide-PbAu SIS tunnel junctions are fabricated using a bridge lift-off technique. The LO power is provided by Gunn oscillators followed by doublers or triplers. The receivers in the 85 to 120 GHz band have noise temperatures of <100 K, while the receivers in the 200 to 300 GHz band have noise temperatures in the range from 200 to 300 K. These dual channel receivers are mounted in 4.5 K closed cycle refrigerators. They are in continuous use on the three element millimeter-wavelength interferometer array

  11. NASA 60 GHz intersatellite communication link definition study. Addendum A: Mixed baseband and IF signals

    1986-01-01

    As part of a definition study for a 60 GHz intersatellite communications link system (ICLS), baseline design concepts for a channelized crosslink were identified. The crosslink would allow communications between geostationary satellites of the planned Tracking and Data Acquisition System (TDAS) and would accommodate a mixture of frequency translation coherent links (bent pipe links) and baseband-in/baseband-out links (mod/demod links). A 60 GHz communication system was developed for sizing and analyzing the crosslink. For the coherent links this system translates incoming signals directly up to the 60 GHz band; trunks the signals across from one satellite to a second satellite at 60 GHz then down converts to the proper frequency for re-transmission from the second satellite without converting to any intermediate frequencies. For the baseband-in/baseband-out links the baseband data is modulated on to the 60 GHz carrier at the transmitting satellite and demodulated at the receiving satellite. The frequency plan, equipment diagrams, and link calculations are presented along with results from sizing and reliability analyses.

  12. High precision 6.8GHz phase locking of coherent laser beams for optical lattice experiment

    Ding, Xun; Sang, Linlin; Zhang, Chen; Jin, Ge; Jiang, Xiao

    2013-12-01

    With the optical phase lock loop (OPLL) we made, we can achieve phase locking at frequency differences ranging from 0.5GHz to 7.5 GHz. This OPLL is fully applicable in atomic physics experiments, mostly in coherent lasers frequency locking. Two kinds of modulation modes were brought to ensure the frequency range and precision: the fast feedback current as the injection current and the slow feedback current to adjust the piezo-electric transducer. This device has been put into an optical lattice platform to lock a laser used for cooling and trapping atoms. The beat signal has a -3dB band width of 1Hz at 6.834GHz, corresponding to the hyperfine splitting of the ground state 87Rb atom.

  13. Digital-photonic synthesis of ultra-low noise tunable signals from RF to 100 GHz

    Fortier, T M; Quinlan, F; Baynes, F N; Metcalf, A J; Hati, A; Ludlow, A; Hinkley, N; Shimizu, M; Ishibashi, T; Campbell, J C; Diddams, S A

    2015-01-01

    The demand for higher data rates and better synchronization in communication and navigation systems necessitates the development of new wideband and tunable sources with noise performance exceeding that provided by traditional oscillators and synthesizers. Precision synthesis is paramount for providing frequency references and timing in a broad range of applications including next-generation telecommunications, high precision measurement, and radar and sensing. Here we describe a digital-photonic synthesizer (DPS) based on optical frequency division that enables the generation of widely tunable signals from near DC to 100 GHz with a fractional frequency instability of 1 part in 10^15. The spectral purity of the DPS derived signals represents an improvement in close-to-carrier noise performance over the current state-of-the-art of nearly 7 orders of magnitude in the W-band (100 GHz), and up to 5 orders of magnitude in the X-band (10 GHz).

  14. The Rare 23.1-GHz Methanol Masers in NGC 7538 IRS 1

    Galván-Madrid, Roberto; Ramírez, Edgar A; Kurtz, Stan; Araya, Esteban; Hofner, Peter

    2010-01-01

    We present high angular resolution (FWHM_beam < 0.2") observations of the 23.1-GHz methanol (CH_3OH) transition toward the massive-star forming region NGC 7538 IRS 1. The two velocity components previously reported by Wilson et al. are resolved into distinct spatial features with brightness temperatures (T_B) greater than 10^4 K, proving their maser nature. Thus, NGC 7538 IRS 1 is the third region confirmed to show methanol maser emission at this frequency. The brighter 23.1-GHz spot coincides in position with a rare formaldehyde (H_2CO) maser, and marginally with a 22.2-GHz water (H_2O) maser, for which we report archival observations. The weaker CH_3OH spot coincides with an H_2O maser. The ratio of T_B for the 23.1-GHz masers to that of the well-known 12.2-GHz CH_3OH masers in this region roughly agrees with model predictions. However, the 23.1-GHz spots are offset in position from the CH_3OH masers at other frequencies. This is difficult to interpret in terms of models that assume that all the masers a...

  15. Design of CMOS Power Amplifier for Millimeter Wave Systems at 70 GHz

    Rashid A. Saeed

    2013-02-01

    Full Text Available In this paper, a new CMOS power amplifier that can operate at 70 GHz is designed and developed. The advantages of using 70 GHz at millimeter wave (mmW band is the huge amount of bandwidth available for various purposes whether they are in the cellular industry or manufacture devices such as high bandwidth wireless LAN and low attenuation of bandwidth frequencies around 70 GHz bands comparing with 60 GHz. Design power amplifiers at 70 GHz are quite challenges task. The complication such as the stability of the amplifier is difficult and hard to be achieved. In this paper, we design power amplifier with 3 single ended, common source stages biased in class A. The proposed circuit resulted in a stable power amplifier capable of working at 70 GHz frequency. The purpose of using three stages is not only to maximize gain but also to increase isolation against reflections. We found that this configuration has many advantages in terms of lower power supply required, leading to higher efficiencyand good linearity. The first stage is biased at a peak Fmax biased of 0.2 mA/μm to maximize the gain to 10.58 dB. The second and third stages are biased at optimum linearity current density of 0.28 mA/μm.

  16. Electrooptic modulation up to 40 GHz in a barium titanate thin film waveguide modulator

    Tang, Pingsheng; Towner, D. J.; Hamano, T.; Meier, A. L.; Wessels, B. W.

    2004-11-01

    The high frequency operation of a low-voltage electrooptic modulator based on a strip-loaded BaTiO3 thin film waveguide structure has been demonstrated. The epitaxial BaTiO3 thin film on an MgO substrate forms a composite structure with a low effective dielectric constant of 20.8 at 40 GHz. A 3.9 V half-wave voltage with a 3.7 GHz 3-dB bandwidth and a 150 pm/V effective electrooptic coefficient is obtained for the 3.2mm-long modulator at 1.55 μm. Broadband modulation up to 40 GHz is measured with a calibrated detection system. Numerical simulations indicate that the BaTiO3 thin film modulator has the potential for a 3-dB operational bandwidth in excess of 40 GHz through optimized design.

  17. A 20-GHz ultra-high-speed InP DHBT comparator

    An ultra-high-speed, master-slave voltage comparator circuit is designed and fabricated using InP/GaInAs double heterojunction bipolar transistor technology with a current gain cutoff frequency of 170 GHz. The complete chip die, including bondpads, is 0.75 × 1.04 mm2. It consumes 440 mW from a single −4 V power supply, excluding the clock part. 77 DHBTs have been used in the monolithic comparator. A full Nyquist test has been performed up to 20 GHz, with the input sensitivity varying from 6 mV at 10 GHz to 16 mV at 20 GHz. To our knowledge, this is the first InP based integrated circuit including more than 70 DHBTs, and it achieves the highest sampling rate found on the mainland of China. (semiconductor integrated circuits)

  18. DESIGN OF STEPPED IMPEDANCE LOW PASS FILTER AT 2.4GHz

    Vishakha Dayal Shrivastava*, Vandana Vikas Thakare

    2016-01-01

    In this era, life can't be envisioned without wireless communication. The microwave filter is a component which gives frequency selectivity in mobile, radar, satellite communication systems working at microwave frequency. Microwave low pass filter attenuates the unwanted signal above cut off frequency. For stepped impedance filter design high and low impedance lines are used. This paper describes designing of Chebyshev approximated stepped impedance low pass filter at 2.4 GHz  with t...

  19. Period-Doubling in 10 GHz Gain-Switched DFB Laser Diode

    WU Jian; QIU Ji-Fang; LIN Jin-Tong

    2007-01-01

    The distinct period doubling behaviour in a 10 GHz gain-switched (GS) DFB laser is experimentally investigatedin frequency domain and in time domain. The period doubling occurs as the frequency of the rf driving signal is close to or higher than the -3 dB cutoff frequency of the DFB laser diode, and the amplitude of the rf driving signal required to achieve period doubling increases linearly with the increasing bias current of the laser diode.

  20. A monolithic 60 GHz balanced low noise amplifier

    This paper presents a 60 GHz balanced low noise amplifier. Compared with single-ended structures, the balanced structure can obtain a better input/output return loss, a lower noise figure (NF), a 3 dB improvement of the 1 dB compression point, a 6 dB improvement of IM3 and a doubled dynamic range. Each single-ended amplifier in this paper uses a four-stage cascade structure to achieve a high gain in broadband. At the operating frequency range of 59–64 GHz, the small signal gain of the balanced amplifier is more than 20 dB. Both the input and output return losses are less than −12 dB. The output 1 dB compression power is 10.5 dBm at 60 GHz. The simulation result for the NF is better than 3.9 dB. The chip is fabricated using a 0.15 μm GaAs pHEMT process with a size of 2.25 × 1.7 mm2. (paper)

  1. Making Maps from Planck LFI 30GHz Data

    Ashdown, M A J; Balbi, A; Bartlett, J G; Borrill, J; Cantalupo, C; De Gasperis, G; Górski, K M; Heikkila, V; Hivon, E; Keihanen, E; Kurki-Suonio, H; Lawrence, C R; Natoli, P; Poutanen, T; Prunet, S; Reinecke, M; Stompor, R; Wandelt, B

    2007-01-01

    This paper is one of a series describing the performance and accuracy of map-making codes as assessed by the Planck CTP working group. We compare the performance of multiple codes written by different groups for making polarized maps from Planck-sized, all-sky cosmic microwave background (CMB) data. Three of the codes are based on destriping algorithm, whereas the other three are implementations of a maximum-likelihood algorithm. Previous papers in the series described simulations at 100 GHz (Poutanen et al. 2006) and 217 GHz (Ashdown et al. 2006). In this paper we make maps (temperature and polarisation) from the simulated one-year observations of four 30 GHz detectors of Planck Low Frequency Instrument (LFI). We used Planck Level S simulation pipeline to produce the observed time-ordered-data streams (TOD). Our previous studies considered polarisation observations for the CMB only. For this paper we increased the realism of the simulations and included polarized galactic foregrounds to our sky model. Our si...

  2. NASA 60 GHz intersatellite communication link definition study. Baseline document

    1986-01-01

    The overall system and component concepts for a 60 GHz intersatellite communications link system (ICLS) are described. The ICLS was designed to augment the capabilities of the current Tracking and Data Relay Satellite System (TDRSS), providing a data rate capacity large enough to accommodate the expected rates for user satellites (USAT's) in the post-1995 timeframe. The use of 60 GHz for the anticipated successor to TDRSS, the Tracking and Data Acquisition System (TDAS), was selected because of current technology development that will enable multigigibit data rates. Additionally, the attenuation of the earth's atmosphere at 60 GHz means that there is virtually no possibility of terrestrially generated interference (intentional or accidental) or terrestrially based intercept. The ICLS includes the following functional areas: (1) the ICLS payload package on the GEO TDAS satellite that communicates simultaneously with up to five LEO USAT's; (2) the payload package on the USAT that communicates with the TDAS satellite; and (3) the crosslink payload package on the TDAS satellite that communicates with another TDAS satellite. Two methods of data relay on-board the TDAS spacecraft were addressed. One is a complete baseband system (demod and remod) with a bi-directional 2 Gbps data stream; the other is a channelized system wherein some of the channels are baseband and others are merely frequency translated before re-transmission. Descriptions of the TDAS antenna, transmitter, receiver, and mechanical designs are presented.

  3. AN ACCURATE FLUX DENSITY SCALE FROM 1 TO 50 GHz

    Perley, R. A.; Butler, B. J., E-mail: RPerley@nrao.edu, E-mail: BButler@nrao.edu [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)

    2013-02-15

    We develop an absolute flux density scale for centimeter-wavelength astronomy by combining accurate flux density ratios determined by the Very Large Array between the planet Mars and a set of potential calibrators with the Rudy thermophysical emission model of Mars, adjusted to the absolute scale established by the Wilkinson Microwave Anisotropy Probe. The radio sources 3C123, 3C196, 3C286, and 3C295 are found to be varying at a level of less than {approx}5% per century at all frequencies between 1 and 50 GHz, and hence are suitable as flux density standards. We present polynomial expressions for their spectral flux densities, valid from 1 to 50 GHz, with absolute accuracy estimated at 1%-3% depending on frequency. Of the four sources, 3C286 is the most compact and has the flattest spectral index, making it the most suitable object on which to establish the spectral flux density scale. The sources 3C48, 3C138, 3C147, NGC 7027, NGC 6542, and MWC 349 show significant variability on various timescales. Polynomial coefficients for the spectral flux density are developed for 3C48, 3C138, and 3C147 for each of the 17 observation dates, spanning 1983-2012. The planets Venus, Uranus, and Neptune are included in our observations, and we derive their brightness temperatures over the same frequency range.

  4. Status of the design of the 200 GHz FOM-fusion-FEM

    A Free Electron Maser is being designed for ECRH applications on future fusion devices. The FEM will have an output power of 1 MW, a central frequency of 200 GHz and will be adjustable over the complete frequency range of 125 GHz to 250 GHz. The FEM operates with a thermionic electron gun. Fast tunability is achieved by variation of the voltage of the 2 MeV electrostatic accelerator. The undulator and mmw system are located in a terminal at a voltage of 2 MV, inside a vessel filled with SF6 at a pressure of 7 bar. After interaction with the mm waves in the undulator, the energy of the electron beam will be recovered by means of a decelerator and a multi-stage depressed collector. The -low emittance- electron beam will be completely straight to minimize current losses to less than 20 mA. This current is to be delivered by the 2 MV dc accelerating voltage power supply. Simulations indicate that the overall efficiency will be over 50%. The interaction between the electron beam and the mm waves is simulated using both a 1-D, non-stationary code and a fully 3-D, stationary, amplifier code. Results with both codes will be presented, indicating that with a beam current of 12 A an output power of 1 MW can be generated for all required frequencies with a beam energy ranging from 1.3 MeV (for 125 GHz) to 2 MeV (for 250 GHz)

  5. 60 GHz wireless data transfer for tracker readout systems—first studies and results

    To allow highly granular trackers to contribute to first level trigger decisions or event filtering, a fast readout system with very high bandwidth is required. Space, power and material constraints, however, pose severe limitations on the maximum available bandwidth of electrical or optical data transfers. A new approach for the implementation of a fast readout system is the application of a wireless data transfer at a carrier frequency of 60 GHz. The available bandwidth of several GHz allows for data rates of multiple Gbps per link. 60 GHz transceiver chips can be produced with a small form factor and a high integration level. A prototype transceiver currently under development at the University of Heidelberg is briefly described in this paper. To allow easy and fast future testing of the chip's functionality, a bit error rate test has been developed with a commercially available transceiver. Crosstalk might be a big issue for a wireless readout system with many links in a tracking detector. Direct crosstalk can be avoided by using directive antennas, linearly polarized waves and frequency channeling. Reflections from tracking modules can be reduced by applying an absorbing material like graphite foam. Properties of different materials typically used in tracking detectors and graphite foam in the 60 GHz frequency range are presented. For data transmission tests, links using commercially available 60 GHz transmitters and receivers are used. Studies regarding crosstalk and the applicability of graphite foam, Kapton horn antennas and polarized waves are shown

  6. 60 GHz wireless data transfer for tracker readout systems—first studies and results

    Dittmeier, S.; Berger, N.; Schöning, A.; Soltveit, H. K.; Wiedner, D.

    2014-11-01

    To allow highly granular trackers to contribute to first level trigger decisions or event filtering, a fast readout system with very high bandwidth is required. Space, power and material constraints, however, pose severe limitations on the maximum available bandwidth of electrical or optical data transfers. A new approach for the implementation of a fast readout system is the application of a wireless data transfer at a carrier frequency of 60 GHz. The available bandwidth of several GHz allows for data rates of multiple Gbps per link. 60 GHz transceiver chips can be produced with a small form factor and a high integration level. A prototype transceiver currently under development at the University of Heidelberg is briefly described in this paper. To allow easy and fast future testing of the chip's functionality, a bit error rate test has been developed with a commercially available transceiver. Crosstalk might be a big issue for a wireless readout system with many links in a tracking detector. Direct crosstalk can be avoided by using directive antennas, linearly polarized waves and frequency channeling. Reflections from tracking modules can be reduced by applying an absorbing material like graphite foam. Properties of different materials typically used in tracking detectors and graphite foam in the 60 GHz frequency range are presented. For data transmission tests, links using commercially available 60 GHz transmitters and receivers are used. Studies regarding crosstalk and the applicability of graphite foam, Kapton horn antennas and polarized waves are shown.

  7. VLBI observations of 3C273 at 22GHz and 43 GHz. I: Search for short time-scale structural variation

    Mantovani, F.; Junor, W.; Valerio, C; McHardy, I.

    1999-01-01

    The results of VLBI observations of the quasar 3C273, obtained during a multi-frequency campaign in late 1992 in the radio, millimeter and X-ray bands are presented and discussed. The VLBI observations were made at 22 GHz with a Global Array and at 43 GHz with the Very Long Baseline Array. Hybrid maps and modelfits were made in order to look for any short time scale structural variations of the inner part of the radio jet. In 42 days 3C273 was observed 5 times at roughly 10 day intervals. The...

  8. Low noise frequency synthesizer of a centimeter range wave

    I. S. Tsvelikh

    2007-06-01

    Full Text Available A highly stable, low noise 10.7 GHz frequency synthesizer for radio-relay link transceiver is presented. The basic elements of synthesizer are electrically tuned 5.35 GHz dielectric ring oscillator and transistor frequency doubler.

  9. Varactor-Tuned Dual-Mode Frequency Discriminator for Instantaneous Frequency Measurements

    Moscoso Mártir, Álvaro; Molina-Fernández, Íñigo; Hong, Jiasheng

    2013-01-01

    In this paper a novel varactor-tuned frequency discriminator that makes use of two tunable dual-mode microstrip resonators is demonstrated which doubles the discriminator tuning bandwidth. To prove its validity a prototype of the tunable dual-mode microstrip resonator is manufactured and the measured results are used to study the frequency discriminator response. This new approach can cover almost an octave of frequency range from 1.05 to 2 GHz with a sensitivity of 45 V/GHz and 21 V/GHz for ...

  10. Recent operating experience with Varian 70 GHz and 140 GHz gyrotrons

    The design features and initial test results of Varian 70 GHz and 140 GHz CW gyrotrons are presented. The first experimental 140 GHz tube has achieved an output power of 102 kW at 24% efficiency under pulsed conditions in the desired TE0310 cavity mode. Further tests aimed at achieving the design goal of 100 kW CW are currently underway. The 70 GHz tube has achieved an output power of 200 kW under pulsed conditions and possesses a wide dynamic range for output power variations. 6 refs., 8 figs

  11. Antenne Design for 24 GHz and 60 GHz Emerging Microwave Applications

    Jansen, F.; Dolmans, W.M.C.

    2006-01-01

    In this project integrated antennas on a LAMP3 substrate for automotive radar systems at 24 GHz and wireless networks at 60 GHz have been designed. The most severe requirements on the antennas were the large bandwidth, which can not be met with conventional patch antennas. A tapered slot antenna and a bow-tie slot antenna both for 24 GHz as well as a scaled version of the bow-tie slot antenna designed for 60 GHz were fabricated. The return loss bandwidth as well as the radiation patterns of t...

  12. An Accurate Flux Density Scale from 1 to 50 GHz

    Perley, Rick A

    2012-01-01

    We develop an absolute flux density scale for cm-wavelength astronomy by combining accurate flux density ratios determined by the VLA between the planet Mars and a set of potential calibrators with the Rudy thermophysical emission model of Mars, adjusted to the absolute scale established by WMAP. The radio sources 3C123, 3C196, 3C286 and 3C295 are found to be varying at a level of less than ~5% per century at all frequencies between 1 and 50 GHz, and hence are suitable as flux density standards. We present polynomial expressions for their spectral flux densities, valid from 1 to 50 GHz, with absolute accuracy estimated at 1-3% depending on frequency. Of the four sources, 3C286 is the most compact and has the flattest spectral index, making it the most suitable object on which to establish the spectral flux density scale. The sources 3C48, 3C138, 3C147, NGC7027, NGC6542, and MWC349 show significant variability on various timescales. Polynomial coefficients for the spectral flux density are developed for 3C48, ...

  13. One Innovation of Mechanical Polishing Apparatus for Surface Treatment of 6 GHz TESLA Superconducting Cavity

    YU; Guo-long; A.A.Rossi; R.K.Thakur; V.Palmieri

    2013-01-01

    6 GHz spinning seamless superconducting radio frequency(SRF)cavities are a very useful tool for testing alternative surface treatments in the fabrication of TESLA cavity.However,the surface is damaged in internal part for the using of the collapsible mandrel during spinning.The first important step of the

  14. Low-jitter and high-power 40 GHz all-active mode-locked lasers

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin;

    2004-01-01

    A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power....

  15. Phase locking of 270-440 GHz Josephson flux flow oscillators

    Mygind, Jesper; Koshelets, V.P.; Shitov, S.V.; Filippenko, L.V.; Vaks, V.L.; Baryshev, A.B.; Luinge, W.; Whyborn, N.

    1999-01-01

    External phase locking of a Josephson flux flow oscillator (FFO) to a 10 MHz reference oscillator is demonstrated experimentally in the frequency range 270-440 GHz. A linewidth as low as 1 Hz (as determined by the resolution bandwidth of the spectrum analyser) has been measured. This linewidth is...

  16. Advanced Wireless Local Area Networks in the Unlicensed Sub-1GHz ISM-bands

    Aust, S.H.

    2014-01-01

    This dissertation addresses the challenges of wireless local area networks (WLANs) that operate in the unlicensed sub-1GHz industrial, scientific, and medical (ISM) band. Frequencies in the 900MHz spectrum enable a wider coverage due to the longer propagation characteristics of the radio waves. To u

  17. Antenne Design for 24 GHz and 60 GHz Emerging Microwave Applications

    Jansen, F.; Dolmans, W.M.C.

    2006-01-01

    In this project integrated antennas on a LAMP3 substrate for automotive radar systems at 24 GHz and wireless networks at 60 GHz have been designed. The most severe requirements on the antennas were the large bandwidth, which can not be met with conventional patch antennas. A tapered slot antenna and

  18. Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions

    Padmanabhan, Sharmila; Fung, King Man; Kangaslahti, Pekka P.; Peralta, Alejandro; Soria, Mary M.; Pukala, David M.; Sin, Seth; Samoska, Lorene A.; Sarkozy, Stephen; Lai, Richard

    2012-01-01

    Packaging of MMIC LNA (monolithic microwave integrated circuit low-noise amplifier) chips at frequencies over 200 GHz has always been problematic due to the high loss in the transition between the MMIC chip and the waveguide medium in which the chip will typically be used. In addition, above 200 GHz, wire-bond inductance between the LNA and the waveguide can severely limit the RF matching and bandwidth of the final waveguide amplifier module. This work resulted in the development of a low-loss quartz waveguide transition that includes a capacitive transmission line between the MMIC and the waveguide probe element. This capacitive transmission line tunes out the wirebond inductance (where the wire-bond is required to bond between the MMIC and the probe element). This inductance can severely limit the RF matching and bandwidth of the final waveguide amplifier module. The amplifier module consists of a quartz E-plane waveguide probe transition, a short capacitive tuning element, a short wire-bond to the MMIC, and the MMIC LNA. The output structure is similar, with a short wire-bond at the output of the MMIC, a quartz E-plane waveguide probe transition, and the output waveguide. The quartz probe element is made of 3-mil quartz, which is the thinnest commercially available material. The waveguide band used is WR4, from 170 to 260 GHz. This new transition and block design is an improvement over prior art because it provides for better RF matching, and will likely yield lower loss and better noise figure. The development of high-performance, low-noise amplifiers in the 180-to- 700-GHz range has applications for future earth science and planetary instruments with low power and volume, and astrophysics array instruments for molecular spectroscopy. This frequency band, while suitable for homeland security and commercial applications (such as millimeter-wave imaging, hidden weapons detection, crowd scanning, airport security, and communications), also has applications to

  19. Lumped element kinetic inductance detectors maturity for space-borne instruments in the range between 80 and 180~GHz

    Catalano, A; Bourrion, O; Calvo, M; Coiffard, G; D'Addabbo, A; Goupy, J; Sueur, H Le; Macìas-Pérez, J; Monfardini, A

    2015-01-01

    This work intends to give the state-of-the-art of our knowledge of the performance of LEKIDs at millimetre wavelengths (from 80 to 180~GHz). We evaluate their optical sensitivity under typical background conditions and their interaction with ionising particles. Two LEKID arrays, originally designed for ground-based applications and composed of a few hundred pixels each, operate at a central frequency of 100, and 150~GHz ($\\Delta \

  20. A study of broadband Faraday rotation and polarization behaviour over 1.3--10 GHz in 36 discrete radio sources

    Anderson, C S; Feain, I J

    2016-01-01

    We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely-sampled frequency band. Our sample was selected on the basis of polarization behaviour apparent in narrowband archival data at 1.4 GHz: half the sample show complicated frequency-dependent polarization behaviour (i.e. Faraday complexity) at these frequencies, while half show comparatively simple behaviour (i.e. they appear Faraday simple). We re-observed the sample using the Australia Telescope Compact Array (ATCA) in full polarization, with 6 GHz of densely sampled frequency coverage spanning 1.3 to 10 GHz. We have devised a general polarization modelling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behaviour in almost every source in our sample. Several sources exhibit particularly remarkable polarization behaviour. By comparing our new and archival data, we have identified temporal variabili...

  1. Microphonics detuning compensation in 3.9 GHZ superconducting RF cavities

    Ruben Carcagno et al.

    2003-10-20

    Mechanical vibrations can detune superconducting radio frequency (SCRF) cavities unless a tuning mechanism counteracting the vibrations is present. Due to their narrow operating bandwidth and demanding mechanical structure, the 13-cell 3.9GHz SCRF cavities for the Charged Kaons at Main Injector (CKM) experiment at Fermilab are especially susceptible to this microphonic phenomena. We present early results correlating RF frequency detuning with cavity vibration measurements for CKM cavities; initial detuning compensation results with piezoelectric actuators are also presented.

  2. Towards the Realization of Graphene Based Flexible Radio Frequency Receiver

    Maruthi N. Yogeesh

    2015-11-01

    Full Text Available We report on our progress and development of high speed flexible graphene field effect transistors (GFETs with high electron and hole mobilities (~3000 cm2/V·s, and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM radio receiver operating at 2.4 GHz.

  3. Mode-locking and frequency mixing at THz pulse repetition rates in a sampled-grating DBR mode-locked laser

    Hou, Lianping; Haji, Mohsin; John H. Marsh

    2014-01-01

    We report a sampled grating distributed Bragg reflector (SGDBR) laser with two different gratings which mode-lock independently at respective pulse repetition frequencies of 640 and 700 GHz. The device operates in distinct regimes depending on the bias conditions, with stable pulse trains observed at 640 GHz, 700 GHz, the mean repetition frequency of 666 GHz, and the sum frequency of 1.34 THz (due to nonlinear mixing). Performance is consistent and highly reproducible with exceptional stabili...

  4. Optimal GHZ Paradox for Three Qubits

    Ren, Changliang; Su, Hong-Yi; Xu, Zhen-Peng; Wu, Chunfeng; Chen, Jing-Ling

    2015-08-01

    Quatum nonlocality as a valuable resource is of vital importance in quantum information processing. The characterization of the resource has been extensively investigated mainly for pure states, while relatively less is know for mixed states. Here we prove the existence of the optimal GHZ paradox by using a novel and simple method to extract an optimal state that can saturate the tradeoff relation between quantum nonlocality and the state purity. In this paradox, the logical inequality which is formulated by the GHZ-typed event probabilities can be violated maximally by the optimal state for any fixed amount of purity (or mixedness). Moreover, the optimal state can be described as a standard GHZ state suffering flipped color noise. The maximal amount of noise that the optimal state can resist is 50%. We suggest our result to be a step toward deeper understanding of the role played by the AVN proof of quantum nonlocality as a useful physical resource.

  5. Design of an UWB Patch Antenna for Dual Frequency Operations

    M.M. Islam

    2014-01-01

    Full Text Available The purpose of this study is to present the development of an Ultra-Wide Band (UWB patch antenna for dual frequency operations. The size of the proposed antenna is 40×40×1.6 mm3 and is excited by micros trip line. The Finite Element Method (FEM based on high frequency electromagnetic simulation software is used in this investigation. Return loss is obtained below -10 dB from 8.39 to 9.7 GHz. It has achieved stable radiation efficiency 84% with gain 3.81 dB and 4.25 dB in the operating frequency band. The antenna generates two separate resonant frequencies to cover UWB band (3.1-10.6 GHz. Lower resonant mode of the antenna has an impedance bandwidth of 940 MHz (9-8.06 GHz and the upper resonant mode has a bandwidth of 1 GHz (10.08-9.08 GHz.

  6. Frequency dependent characteristics of solar impulsive radio bursts

    An investigation was made of the impulsive radio bursts observed in the frequency range 0.245 to 35 GHz. Important results obtained are: (i) Simple type 1 bursts with intensities 0 to 10 f.u. and simple type 2 bursts with intensities 10 to 500 f.u. are predominant in the frequency ranges 1.415 to 4.995 GHz and 4.995 to 8.8 GHz, respectively; (ii) With maxima around 2.7 GHz and 4 GHz for the first and second types respectively, the durations of the radio bursts decrease gradually both towards lower and higher frequencies; (iii) As regards occurrences, the first type dominates in the southern solar hemisphere peaking around 8.8 GHz, whereas the second type favours the north with no well-defined maximum in any frequency; (iv) Both types prefer the eastern hemisphere, the peak occurrences being around 8.8 GHz and 5 GHz for the two successive types, respectively; (c) The spectra of impulsive radio bursts are generally of the inverted U-type with the maximum emission intensity between 5 and 15 GHz. (author)

  7. A Prediction Study of Path Loss Models from 2-73.5 GHz in an Urban-Macro Environment

    Thomas, Timothy; Rybakowski, Marcin; Sun, Shu; Rappaport, Theodore S.; Nguyen, Huan Cong; Kovacs, Istvan; Rodriguez, Ignacio

    2016-01-01

    It is becoming clear that 5G wireless systems will encompass frequencies from around 500 MHz all the way to around 100 GHz. To adequately assess the performance of 5G systems in these different bands, path loss (PL) models will need to be developed across this wide frequency range. The PL models ...

  8. A Prediction Study of Path Loss Models from 2-73.5 GHz in an Urban-Macro Environment

    Thomas, Timothy; Rybakowski, Marcin; Sun, Shu;

    2016-01-01

    It is becoming clear that 5G wireless systems will encompass frequencies from around 500 MHz all the way to around 100 GHz. To adequately assess the performance of 5G systems in these different bands, path loss (PL) models will need to be developed across this wide frequency range. The PL models...

  9. The 60 GHz solid state power amplifier

    Mcclymonds, J.

    1991-01-01

    A new amplifier architecture was developed during this contract that is superior to any other solid state approach. The amplifier produced 6 watts with 4 percent efficiency over a 2 GHz band at 61.5 GHz. The unit was 7 x 9 x 3 inches in size, 5.5 pounds in weight, and the conduction cooling through the baseplate is suitable for use in space. The amplifier used high efficiency GaAs IMPATT diodes which were mounted in 1-diode circuits, called modules. Eighteen modules were used in the design, and power combining was accomplished with a proprietary passive component called a combiner plate.

  10. Advanced Wireless Local Area Networks in the Unlicensed Sub-1GHz ISM-bands

    Aust, S.H.

    2014-01-01

    This dissertation addresses the challenges of wireless local area networks (WLANs) that operate in the unlicensed sub-1GHz industrial, scientific, and medical (ISM) band. Frequencies in the 900MHz spectrum enable a wider coverage due to the longer propagation characteristics of the radio waves. To utilize globally available sub-1GHz (S1G) ISM-bands, the IEEE 802.11ah Task Group started to standardize a new WLAN protocol in 2010. The IEEE 802.11ah WLAN protocol enables moderate data rates over...

  11. Linescan camera evaluation of SSM/I 85.5 GHz sea ice retrieval

    Garrity, Caren; Lubin, Dan; Kern, Stefan; Pedersen, Leif Toudal

    2002-01-01

    cloud cover, for operational purposes. The SSM/I 85.5 GHz channels offer a spatial resolution of 12.5 km, which is sufficient to resolve ice edge features and small polynyas; however, there is generally more atmospheric contamination of the sea ice signal at 85.5 GHz than at the lower frequencies (19...... misclassify clouds over open water as sea ice, and is therefore unreliable for locating the sea ice edge. The best algorithm for locating the sea ice edge is found to be the SEA LION algorithm, which explicitly uses meteorological reanalysis data to correct for atmospheric contamination. For total sea ice...

  12. Low-noise parametric amplification at 35 GHz in a single Josephson tunnel junction

    Mygind, Jesper; Pedersen, Niels Falsig; Sørensen, O. H.; Dueholm, B.; Levinsen, M. T.

    1979-01-01

    Parametric amplification at 35 GHz has been obtained using a single Josephson tunnel junction as the active element. The amplifier was operated in the singly quasidegenerate mode with a pump frequency at 70 GHz. The noise temperature was measured and found correlated with the gain. At the highest...... gain achieved, 11.6 dB, the noise temperature was 400 K. The noise temperature was reduced considerably by decreasing the gain. At 8 and 4 dB we found 165±25 K and 50±30 K, respectively. Applied Physics Letters is copyrighted by The American Institute of Physics....

  13. 3D printed 20/30-GHz dual-band offset stepped-reflector antenna

    Menendez, Laura G.; Kim, Oleksiy S.; Persson, Frank;

    2015-01-01

    peak directivity of 36.7 dB and 40.4 dB at 20 and 30 GHz, respectively; this corresponds to an aperture efficiency of 61 % and 64 %, respectively. These results demonstrate that 3D printing is a viable manufacturing technology for medium-sized high-frequency antennas.......This paper documents the manufacturing by selective laser sintering of a 20/30 GHz dual-band circularly polarized offset stepped-reflector antenna for K- and Ka-band satellite communication. The manufactured antenna has been measured at the DTU-ESA Spherical Near-Field Antenna Test Facility with a...

  14. Radio properties of Compact Steep Spectrum and GHz-Peaked Spectrum radio sources

    Orienti, M

    2015-01-01

    Compact steep spectrum (CSS) and GHz-peaked spectrum (GPS) radio sources represent a large fraction of the extragalactic objects in flux density-limited samples. They are compact, powerful radio sources whose synchrotron peak frequency ranges between a few hundred MHz to several GHz. CSS and GPS radio sources are currently interpreted as objects in which the radio emission is in an early evolutionary stage. In this contribution I review the radio properties and the physical characteristics of this class of radio sources, and the interplay between their radio emission and the ambient medium of the host galaxy.

  15. Clean Beam Patterns with Low Crosstalk Using 850 GHz Microwave Kinetic Inductance Detectors

    Yates, S. J. C.; Baselmans, J. J. A.; Baryshev, A. M.; Doyle, S.; Endo, A.; Ferrari, L.; Hochgürtel, S.; Klein, B.

    2014-09-01

    We present modeling of distributed /4 microwave kinetic inductance detectors (MKIDs) showing how electromagnetic cross coupling between the MKID resonators can occur at frequencies corresponding to the microwave readout signal (4-8 GHz). We then show system beam pattern measurements in the reimaged focal plane of a 72 detector array of lens-antenna coupled MKIDs at 850 GHz, which enables a direct measure of any residual optical crosstalk. With use of transmission line bridges we see no residual cross coupling between MKIDs and hence low crosstalk down to the 30 dB level, with near Gaussian shape (limited by reimaging optics) to 10 dB level.

  16. 5.8 GHz ophthalmic microwave applicator for treatment of choroidal melanoma

    We report on the use of a 5.8 GHz microwave applicator to treat choroidal melanoma (Greene) in rabbits. The physical requirements needed to treat these intraocular tumors are quite different from those encountered elsewhere in the body. From a trans-scleral approach the penetration needed is minimal (5 to 10 mm.). The fibrous sclera is the only structure between the heat source and the tumor. The sclera has a relatively low water content when compared to tumor. This fact in addition to the frequency dependent interactions of tissue and electromagnetic radiation, results in an advantage to the use of the 5.8 GHz microwave device in treating intraocular malignancies

  17. The Australia Telescope 20GHz Survey: Hardware, Observing Strategy, and Scanning Survey Catalog

    Hancock, Paul J; Kesteven, Michael J; Ekers, Ronald D; Sadler, Elaine M; Murphy, Tara; Massardi, Marcella; Ricci, Roberto; Calabretta, Mark; de Zotti, Gianfranco; Edwards, Philip G; Ekers, Jennifer A; Jackson, Carole A; Leach, Mark; Phillips, Chris; Sault, Robert J; Staveley-Smith, Lister; Subrahmanyan, Ravi; Walker, Mark A; Wilson, Warwick E

    2011-01-01

    The Australia Telescope 20GHz (AT20G) survey is a large area (2{\\pi} sr), sensitive (40mJy), high frequency (20GHz) survey of the southern sky. The survey was conducted in two parts: an initial fast scanning survey, and a series of more accurate follow-up observations. The follow-up survey catalog has been presented by Murphy et al. 2010. In this paper we discuss the hardware setup and scanning survey strategy as well as the production of the scanning survey catalog.

  18. Note: Efficient generation of optical sidebands at GHz with a high-power tapered amplifier

    Two methods using a laser-diode tapered amplifier to produce high-power, high-efficiency optical frequency sidebands over a wide tunable frequency range are studied and compared. For a total output of 500 mW at 811 nm, 20% of the power can be placed in each of the first-order sidebands. Functionality and characterization are presented within the sideband frequency region of 0.8–2.3 GHz, and it is shown that both methods can be applied beyond this frequency range. These methods provide a versatile and effective tool for atomic physics experiments

  19. Folded down-conversion mixer for a 60 GHz receiver architecture in 65-nm CMOS technology

    Najam Muhammad AMIN; Zhi-gong WANG‡; Zhi-qun LI

    2014-01-01

    We present the design of a folded down-conversion mixer which is incorporated at the final down-conversion stage of a 60 GHz receiver. The mixer employs an ac-coupled current reuse transconductance stage. It performs well under low supply voltages, and is less sensitive to temperature variations and process spread. The mixer operates at an input radio frequency (RF) band ranging from 10.25 to 13.75 GHz, with a fixed local oscillator (LO) frequency of 12 GHz, which down-converts the RF band to an intermediate frequency (IF) band ranging from dc to 1.75 GHz. The mixer is designed in a 65 nm low power (LP) CMOS process with an active chip area of only 0.0179 mm2. At a nominal supply voltage of 1.2 V and an IF of 10 MHz, a maximum voltage conversion gain (VCG) of 9.8 dB, a double sideband noise figure (DSB-NF) of 11.6 dB, and a linearity in terms of input 1 dB compression point (Pin,1dB) of−13 dBm are measured. The mixer draws a current of 5 mA from a 1.2 V supply dissipating a power of only 6 mW.

  20. A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies

    Smith, Albert A.; Corzilius, Björn; Bryant, Jeffrey A.; DeRocher, Ronald; Woskov, Paul P.; Temkin, Richard J.; Griffin, Robert G.

    2012-10-01

    We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz (1H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 GHz. A coiled TE011 resonator acts as both an NMR coil and microwave resonator, and a double balanced (1H, 13C) radio frequency circuit greatly stabilizes the NMR performance. A new 140 GHz microwave bridge has also been developed, which utilizes a four-phase network and ELDOR channel at 8.75 GHz, that is then multiplied and mixed to obtain 140 GHz microwave pulses with an output power of 120 mW. Nutation frequencies obtained are as follows: 6 MHz on S = 1/2 electron spins, 100 kHz on 1H, and 50 kHz on 13C. We demonstrate basic EPR, ELDOR, ENDOR, and DNP experiments here. Our solid effect DNP results demonstrate an enhancement of 144 and sensitivity gain of 310 using OX063 trityl at 80 K and an enhancement of 157 and maximum sensitivity gain of 234 using Gd-DOTA at 20 K, which is significantly better performance than previously reported at high fields (⩾3 T).

  1. TWT design requirements for 30/20 GHz digital communications' satellite

    Stankiewicz, N.; Anzic, G.

    1979-01-01

    The rapid growth of communication traffic (voice, data, and video) requires the development of additional frequency bands before the 1990's. The frequencies currently in use for satellite communications at 6/4 GHz are crowded and demands for 14/12 GHz systems are increasing. Projections are that these bands will be filled to capacity by the late 1980's. The next higher frequency band allocated for satellite communications is at 30/20 GHz. For interrelated reasons of efficiency, power level, and system reliability criteria, a candidate for the downlink amplifier in a 30/20 GHz communications' satellite is a dual mode traveling wave tube (TWT) equipped with a highly efficient depressed collector. A summary is given of the analyses which determine the TWT design requirements. The overall efficiency of such a tube is then inferred from a parametric study and from experimental data on multistaged depressed collectors. The expected TWT efficiency at 4 dB below output saturation is 24 percent in the high mode and 22 percent in the low mode.

  2. A 12 GHZ 50 MW Klystron for Support of Accelerator Research

    Sprehn, Daryl; /SLAC; Haase, Andrew; /SLAC; Jensen, Aaron; /SLAC; Jongewaard, Erik; /SLAC; Nantista, Christopher; /SLAC; Vlieks, Arnold; /SLAC

    2011-05-31

    A 12 GHz 50MW X-band klystron is under development at the SLAC National Accelerator Laboratory Klystron Department. The klystron will be fabricated to support programs currently underway at three European Labs; CERN, PSI, and INFN Trieste. The choice of frequency selection was due to the CLIC RF frequency changing from 30 GHz to the European X-band frequency of 11.99 GHz in 2008. Since the Klystron Department currently builds 50MW klystrons at 11.424 GHz known collectively as the XL4 klystrons, it was deemed cost-effective to utilize many XL4 components by leaving the gun, electron beam transport, solenoid magnet and collector unchanged. To realize the rf parameters required, the rf cavities and rf output hardware were necessarily altered. Some improvements to the rf design have been made to reduce operating gradients and increase reliability. Changes in the multi-cell output structure, waveguide components, and the window will be discussed along with testing of the devices. Five klystrons known as XL5 klystrons are scheduled for production over the next two years.

  3. Dependence of Substrate Resistance of RF MOSFET on the Performance of LNA at 60 GHz

    Sari.S

    2012-07-01

    Full Text Available Operations in the 60 GHz band have many potential advantages compared to other unlicensed frequency bands including the availability of large bandwidth (7 GHz and high-transmission power levels. In order to utilize this plentiful resource, it is necessary to study the MOSFET devices at 60 GHz for developing high efficiency low noise amplifier and oscillators. The modeling is mainly based on substrate resistance to improve the operating frequency. #960;-type substrate resistance model of RF MOSFETs are used as composite model for MOSFET. In composite model, core transistor is modeled using BSIM4 and substrate network is added to it. The functionality of this composite model is verified by comparing with that of conventional MOSFET. To study the impact of substrate network, a 60 GHz LNA is constructed. Conventional LNA is designed first and later MOSFET in that LNA are replaced with composite model and comparing performances in both the cases. Within the range of designs, the impact of #960;-type substrate resistance network on noise figure, maximum available gain, maximum stable gain, high frequency noise and stability characteristics of the LNA are significant and reported.

  4. An Assessment of the Use of AMSR E 10 GHz Data for Soil Moisture Estimation in SMEX02

    Hsu, A. Y.; Jackson, T. J.; O'Neill, P. E.

    2003-12-01

    The launch of the Advanced Microwave Scanning Radiometer (AMSR-E) on board the NASA EOS Aqua Satellite has drawn much interest from the scientific community that has been waiting for a low frequency spaceborne microwave radiometer (instrument was developed by the National Space Development Agency of Japan (NASDA) and makes dual-polarized microwave measurements at six frequencies: 6.9, 10.7, 18.7, 23.8, 36.5, and 89 GHz. Early examinations of AMSR-E measurements have shown evidence of extensive Radio-Frequency Interference (RFI) in the 6.9 GHz channels, especially over the continental U.S. Due to the contamination of 6.9 GHz data by RFI, it may be necessary to use the next lowest frequency, 10.7 GHz, for soil moisture retrieval. This frequency has been available on the TRMM Microwave Imager for several years; however, the TRMM sensor only provides data between 38 N to 38 S in latitude whereas AMSR-E provides global coverage. We examined the impact of alternative frequencies on soil moisture retrieval using data from the Soil Moisture Experiments in 2002 (SMEX02). SMEX02 took place in Walnut Creek Watershed and surrounding region of Iowa from June 24 to July 12. The experiment focused on microwave remote sensing of soil moisture in an agricultural setting. Land cover in the Walnut Creek Watershed consists of a patchwork of corn and soybean fields, with some isolated forested zones. This presents a challenge to soil moisture retrieval using AMSR-E 10 GHz data. Extensive vegetation sampling was conducted during SMEX02 to provide information to estimate vegetation parameters required by retrieval algorithm. The maps of AMSR-E 10 GHz data over the SMEX02 area from July 2 to 13 show the decrease of brightness temperature (TB) due to precipitation, although the range is not as profound as expected at L band. The Normalized Difference Polarization Index (NDPI), defined as (TBv-TBh)/(TBv+TBh), computed for various frequencies can be considered as indicators of surface

  5. On the origin of 140 GHz emission from the 4 July 2012 solar flare

    Tsap, Yuriy T.; Smirnova, Victoria V.; Morgachev, Alexander S.; Motorina, Galina G.; Kontar, Eduard P.; Nagnibeda, Valery G.; Strekalova, Polina V.

    2016-04-01

    The sub-THz event observed on the 4 July 2012 with the Bauman Moscow State Technical University Radio Telescope RT-7.5 at 93 and 140 GHz as well as Kislovodsk and Metsähovi radio telescopes, Radio Solar Telescope Network (RSTN), GOES, RHESSI, and SDO orbital stations is analyzed. The spectral flux between 93 and 140 GHz has been observed increasing with frequency. On the basis of the SDO/AIA data the differential emission measure has been calculated. It is shown that the thermal coronal plasma with the temperature above 0.5 MK cannot be responsible for the observed sub-THz flare emission. The non-thermal gyrosynchrotron mechanism can be responsible for the microwave emission near 10 GHz but the observed millimeter spectral characteristics are likely to be produced by the thermal bremsstrahlung emission from plasma with a temperature of about 0.1 MK.

  6. On the origin of 140 GHz emission from the 4 July 2012 solar flare

    Tsap, Yuriy T; Morgachev, Alexander S; Motorina, Galina G; Kontar, Eduard P; Nagnibeda, Valery G; Strekalova, Polina V

    2016-01-01

    The sub-THz event observed on the 4 July 2012 with the Bauman Moscow State Technical University Radio Telescope RT-7.5 at 93 and 140~GHz as well as Kislovodsk and Mets\\"ahovi radio telescopes, Radio Solar Telescope Network (RSTN), GOES, RHESSI, and SDO orbital stations is analyzed. The spectral flux between 93 and 140 GHz has been observed increasing with frequency. On the basis of the SDO/AIA data the differential emission measure has been calculated. It is shown that the thermal coronal plasma with the temperature above 0.5~MK cannot be responsible for the observed sub-THz flare emission. The non-thermal gyrosynchrotron mechanism can be responsible for the microwave emission near $10$~GHz but the observed millimeter spectral characteristics are likely to be produced by the thermal bremsstrahlung emission from plasma with a temperature of about 0.1~MK.

  7. Which neuro-physiologic effects at low level 2.45 GHz RF exposure?

    The LS electromagnetic band (1-4 GHz) is widely used both in domestic and industrial domains. Several studies suggested that the biological systems would exhibit a specific sensitivity to the 2.45 GHz microwaves (water resonance frequency). Potential human health hazards and especially a disruption of the cholinergic system have been reported, due to exposure to microwaves even at low power density. This work presents a multi-parametric study of freely moving rat where neuro-physiology was investigated during 70 hours using neurochemical (micro-dialysis technique), electrophysiological, behavioral (vigilance stages quantification) and thermo-physiological approaches. The rats were exposed 24 hours to a 2.45 GHz pulsed electromagnetic field at low power density. In this exposure conditions, no significant effect have been reported. (authors)

  8. A 330-500 GHz Zero-Biased Broadband Tripler Based on Terahertz Monolithic Integrated Circuits

    Ren, Tian-Hao; Zhang, Yong; Yan, Bo; Xu, Rui-Min; Yang, Cheng-Yue; Zhou, Jing-Tao; Jin, Zhi

    2015-02-01

    A 330-500 GHz zero-biased broadband monolithic integrated tripler is reported. The measured results show that the maximum efficiency and the maximum output power are 2% and 194 μW at 348 GHz. The saturation characteristic test shows that the output 1 dB compression point is about -8.5 dBm at 334 GHz and the maximum efficiency is obtained at the point, which is slightly below the 1 dB compression point. Compared with the conventional hybrid integrated circuit, a major advantage of the monolithic integrated circuit is the significant improvement of reliability and consistency. In this work, a terahertz monolithic frequency multiplier at this band is designed and fabricated.

  9. Linescan camera evaluation of SSM/I 85.5 GHz sea ice retrieval

    Garrity, Caren; Lubin, Dan; Kern, Stefan;

    2002-01-01

    cloud cover, for operational purposes. The SSM/I 85.5 GHz channels offer a spatial resolution of 12.5 km, which is sufficient to resolve ice edge features and small polynyas; however, there is generally more atmospheric contamination of the sea ice signal at 85.5 GHz than at the lower frequencies (19...... misclassify clouds over open water as sea ice, and is therefore unreliable for locating the sea ice edge. The best algorithm for locating the sea ice edge is found to be the SEA LION algorithm, which explicitly uses meteorological reanalysis data to correct for atmospheric contamination. For total sea ice...... and 37 GHz) traditionally used for sea ice remote sensing. A self-adjusting algorithm that performs a nonlinear correction for atmospheric moisture, without explicit atmospheric input data, yields the best accuracy over total sea ice concentrations greater than 30%. However, this algorithm can...

  10. A 24GHz Radar Receiver in CMOS

    Kwok, K.C.

    2015-01-01

    This thesis investigates the system design and circuit implementation of a 24GHz-band short-range radar receiver in CMOS technology. The propagation and penetration properties of EM wave offer the possibility of non-contact based remote sensing and through-the-wall imaging of distance stationary or

  11. High frequency carbon nanotube devices

    Goffman, M. F.; Chimot, N.; Mile, E.; Monteverde, M. C.; Bourgoin, J.-P.; Derycke, V.

    2008-08-01

    We investigate high frequency electrical and mechanical performances of carbon nanotube based devices. Using configurations with multiple single-wall nanotubes in parallel, we show that HF nanotube transistors with intrinsic cut-off frequencies as high as 30 GHz can be obtained on rigid substrates. Adapting our process to plastic substrates, we also obtained highly flexible HF transistors showing constant transconductances up to at least 6 GHz, as-measured cut-off frequencies as high as 1 GHz (5-8 GHz after de-embedding) and stable DC performances upon bending. We probed electromechanical properties of individual suspended carbon multiwall nanotubes by using a modified AFM. DC deflection measurements on different devices are in agreement with a continuum model prediction and consistent with a Young's modulus of 0.4 TPa. Preliminary HF measurements on a doubly clamped device showed a resonant frequency of 200MHz consistent with a Young's modulus of 0.43 TPa. This implies that built-in mechanical stress in the case of MWNTs is negligeable.

  12. The 492 GHz emission of Sgr A* constrained by ALMA

    Liu, Hauyu Baobab; Zhao, Jun-Hui; Mills, Elisabeth A C; Requena-Torres, Miguel A; Matsushita, Satoki; Martín, Sergio; Ott, Jürgen; Morris, Mark R; Longmore, Steven N; Brinkerink, Christiaan D; Falcke, Heino

    2016-01-01

    We report linearly polarized continuum emission properties of Sgr A* at $\\sim$492 GHz, based on the Atacama Large Millimeter Array (ALMA) observations. We used the observations of the likely unpolarized continuum emission of Titan, and the observations of C\\textsc{i} line emission, to gauge the degree of spurious polarization. The Stokes I flux of 3.6$\\pm$0.72 Jy during our run is consistent with extrapolations from the previous, lower frequency observations. We found that the continuum emission of Sgr A* at $\\sim$492 GHz shows large amplitude differences between the XX and the YY correlations. The observed intensity ratio between the XX and YY correlations as a function of parallactic angle may be explained by a constant polarization position angle of $\\sim$158$^{\\circ}$$\\pm$3$^{\\circ}$. The fitted polarization percentage of Sgr A* during our observational period is 14\\%$\\pm$1.2\\%. The calibrator quasar J1744-3116 we observed at the same night can be fitted to Stokes I = 252 mJy, with 7.9\\%$\\pm$0.9\\% polariz...

  13. Deep 1.4-GHz observations of diffuse polarized emission

    Carretti, E; Reich, W; Reich, P; Fürst, E; Bernardi, G; Cortiglioni, S; Sbarra, C

    2006-01-01

    Polarized diffuse emission observations at 1.4-GHz in a high Galactic latitude area of the northern Celestial hemisphere are presented. The 3.2 X 3.2 deg^2 field, centred at RA = 10h 58m, Dec = +42deg 18' (B1950), has Galactic coordinates l~172deg, b~+63deg and is located in the region selected as northern target of the BaR-SPOrt experiment. Observations have been performed with the Effelsberg 100-m telescope. We find that the angular power spectra of the E- and B-modes have slopes of beta_E = -1.79 +/- 0.13 and beta_B = -1.74 +/- 0.12, respectively. Because of the very high Galactic latitude and the smooth emission, a weak Faraday rotation action is expected, which allows both a fair extrapolation to Cosmic Microwave Background Polarization (CMBP) frequencies and an estimate of the contamination by Galactic synchrotron emission. We extrapolate the E-mode spectrum up to 32-GHz and confirm the possibility to safely detect the CMBP E-mode signal in the Ka band found in another low emission region (Carretti et a...

  14. ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

    A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid coils from the existing ECR will be enclosed in an iron yoke to produce the axial mirror. Based on a current of 500 A, the final model predicts a minimum B field of 3 kG with injection and extraction mirror ratios of 4.4 and 2.9, respectively. (c) 2000 American Institute of Physics

  15. Development of a 50 MW 30 GHz Gyroklystron Amplifier

    Michael Read; Wesely Lawson, Lawrence Ives, Jeff Neilson

    2009-05-20

    DOE requires sources for testing of high gradient accelerator structures. A power of 50 MW is required at K and Ka band. The pulse length must be ~ 1 microsecond and the pulse repetition frequency at least 100 Hz. At least some applications may require phase stability not offered by a free running oscillator. CCR proposed to build a 50 MW 30 GHz gyrklystron amplifier. This approach would give the required phase stability. The frequency was at the second harmonic of the cycltron frequency and used the TE02 mode. This makes it possible to design a device without an inner conductor, and with a conventional (non-inverted) MIG. This minimizes cost and the risk due to mechanical alignment issues. A detailed design of the gyroklystron was produced. The design was based on simulations of the cavity(ies), electron gun, output coupler and output window. Two designs were produced. One was at the fundamental of the cyclotron frequency. Simulations predicted an output power of 72 MW with an efficiency of 48%. The other was at the second harmonic, producing 37 MW with an efficiency of 37%.

  16. ISM band to U-NII band frequency transverter and method of frequency transversion

    Stepp, Jeffrey David; Hensley, Dale

    2006-09-12

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  17. An FDMA system concept for 30/20 GHz high capacity domestic satellite service

    Berk, G.; Jean, P. N.; Rotholz, E.; White, B. E.

    1982-01-01

    The paper summarizes a feasibility study of a multibeam FDMA satellite system operating in the 30/20 GHz band. The system must accommodate a very high volume of traffic within the restrictions of a 5 kW solar cell array and a 2.5 GHz bandwidth. Multibeam satellite operation reduces the DC power demand and allows reuse of the available bandwidth. Interferences among the beams are brought to acceptable levels by appropriate frequency assignments. A transponder design is presented; it is greatly simplified by the application of a regional concept. System analysis shows that MSK modulation is appropriate for a high-capacity system because it conserves the frequency spectrum. Rain attenuation, a serious problem in this frequency band, is combatted with sufficient power margins and with coding. Link budgets, cost analysis, and weight and power calculations are also discussed. A satellite-routed FDMA system compares favorably in performance and cost with a satellite-switched TDMA system.

  18. Wireless transfer of power by a 35-GHz metamaterial split-ring resonator rectenna

    Maedler, Carsten; Yi, Adrian; Christopher, Jason; Hong, Mi K; Mertiri, Alket; House, Larry; Seren, Huseyin R; Zhang, Xin; Averitt, Richard; Mohanty, Pritiraj; Erramilli, Shyamsunder

    2016-01-01

    Wireless transfer of power via high frequency microwave radiation using a miniature split ring resonator rectenna is reported. RF power is converted into DC power by integrating a rectification circuit with the split ring resonator. The near-field behavior of the rectenna is investigated with microwave radiation in the frequency range between 20-40 GHz with a maximum power level of 17 dBm. The observed resonance peaks match those predicted by simulation. Polarization studies show the expected maximum in signal when the electric field is polarized along the edge of the split ring resonator with the gap and minimum for perpendicular orientation. The efficiency of the rectenna is on the order of 1% for a frequency of 37.2 GHz. By using a cascading array of 9 split ring resonators the output power was increased by a factor of 20.

  19. An offset-fed 20/30 GHz dual-band circularly polarized reflectarray antenna

    Smith, Thomas Gunst; Vesterdal, Niels; Gothelf, Ulrich;

    2013-01-01

    A dual-frequency circularly polarized offset reflectarray antenna for Ka-band satellite communication is presented. The reflectarray is designed using the concentric dual split-loop element which enables full 360° phase adjustment simultaneously in two separate frequency bands. The elements have...... been optimized to suppress the cross-polar reflection. Thereafter, the element data is used for synthesis of the reflectarray layout and computation of the associated radiation patterns. The reflectarray is 400mm × 400mm and radiates LHCP at 19.95 GHz and RHCP at 29.75 GHz. Aperture efficiencies of 58......% and 60% are obtained at these frequencies, and the cross-polarization is more than 25 dB below peak gain....

  20. In-plane Isotropic Microwave Performance of CoZr Trilayer in GHz Range

    Pan, Lulu; Wang, Fenglong; Wang, Wenfeng; Chai, Guozhi; Xue, Desheng

    2016-02-01

    In this paper, we investigate the high frequency performance of Co90Zr10/SiO2/Co90Zr10 trilayers. It is demonstrated that the in-plane isotropic microwave performance is theoretically derived from the solution of the Landau-Lifshitz-Gilbert equation and experimentally achieved in that sandwich structured film. The valuable isotropic behavior comes from the superposition of two uncouple ferromagnetic layers in which the uniaxial magnetic anisotropic fields are equivalent but mutually orthogonal. Moreover, the isotropic microwave performance can be tuned to higher resonance frequency up to 5.3 GHz by employing the oblique deposition technique. It offers a convenient and effective way to achieve an unusual in-plane isotropic microwave performance with high permeability in GHz, holding promising applications for the magnetic devices in the high frequency information technology.

  1. The Atacama Cosmology Telescope: Extragalactic Sources at 148 GHz in the 2008 Survey

    Marriage, T. A.; Juin, J. B.; Lin, Y. T.; Marsden, D.; Nolta, M. R.; Partridge, B.; Ade, P. A. R.; Aguirre, P.; Amiri, M.; Appel, J. W.; Barrientos, L. F.; Battistelli, E. S.; Bond, J. R.; Brown, B.; Burger, B.; Chervenak, J.; Das, S.; Devlin, M. J.; Dicker, S. R.; Doriese, W. B.; Dunkley, J.; Dunner, R.; Essinger-Hileman, T.; Fisher, R. P.; Fowler, J. W.

    2011-01-01

    We report on extragalactic sources detected in a 455 square-degree map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 mJy to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low redshift X-ray selected galaxy clusters. Estimates of the radio to mm-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (> 50 mJy) 148 GHz-selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between .5, 20, and 148 GHz with median spectral indices of alp[ha (sub 5-20) = -0.07 +/- 0.06, alpha (sub 20-148) -0.39 +/- 0.04, and alpha (sub 5-148) = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148 GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is C(sup Sync) = (2.8 +/- 0.3) x 1O (exp-6) micro K(exp 2).

  2. Microwave ablation at 915 MHz vs 2.45 GHz: A theoretical and experimental investigation

    Purpose: The relationship between microwave ablation system operating frequency and ablation performance is not currently well understood. The objective of this study was to comparatively assess the differences in microwave ablation at 915 MHz and 2.45 GHz. Methods: Analytical expressions for electromagnetic radiation from point sources were used to compare power deposition at the two frequencies of interest. A 3D electromagnetic-thermal bioheat transfer solver was implemented with the finite element method to characterize power deposition and thermal ablation with asymmetrical insulated dipole antennas (single-antenna and dual-antenna synchronous arrays). Simulation results were validated against experiments in ex vivo tissue. Results: Theoretical, computational, and experimental results indicated greater power deposition and larger diameter ablation zones when using a single insulated microwave antenna at 2.45 GHz; experimentally, 32 ± 4.1 mm and 36.3 ± 1.0 mm for 5 and 10 min, respectively, at 2.45 GHz, compared to 24 ± 1.7 mm and 29.5 ± 0.6 mm at 915 MHz, with 30 W forward power at the antenna input port. In experiments, faster heating was observed at locations 5 mm (0.91 vs 0.49 °C/s) and 10 mm (0.28 vs 0.15 °C/s) from the antenna operating at 2.45 GHz. Larger ablation zones were observed with dual-antenna arrays at 2.45 GHz; however, the differences were less pronounced than for single antennas. Conclusions: Single- and dual-antenna arrays systems operating at 2.45 GHz yield larger ablation zone due to greater power deposition in proximity to the antenna, as well as greater role of thermal conduction

  3. Microwave ablation at 915 MHz vs 2.45 GHz: A theoretical and experimental investigation

    Curto, Sergio; Taj-Eldin, Mohammed; Fairchild, Dillon; Prakash, Punit, E-mail: prakashp@ksu.edu [Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas 66506 (United States)

    2015-11-15

    Purpose: The relationship between microwave ablation system operating frequency and ablation performance is not currently well understood. The objective of this study was to comparatively assess the differences in microwave ablation at 915 MHz and 2.45 GHz. Methods: Analytical expressions for electromagnetic radiation from point sources were used to compare power deposition at the two frequencies of interest. A 3D electromagnetic-thermal bioheat transfer solver was implemented with the finite element method to characterize power deposition and thermal ablation with asymmetrical insulated dipole antennas (single-antenna and dual-antenna synchronous arrays). Simulation results were validated against experiments in ex vivo tissue. Results: Theoretical, computational, and experimental results indicated greater power deposition and larger diameter ablation zones when using a single insulated microwave antenna at 2.45 GHz; experimentally, 32 ± 4.1 mm and 36.3 ± 1.0 mm for 5 and 10 min, respectively, at 2.45 GHz, compared to 24 ± 1.7 mm and 29.5 ± 0.6 mm at 915 MHz, with 30 W forward power at the antenna input port. In experiments, faster heating was observed at locations 5 mm (0.91 vs 0.49 °C/s) and 10 mm (0.28 vs 0.15 °C/s) from the antenna operating at 2.45 GHz. Larger ablation zones were observed with dual-antenna arrays at 2.45 GHz; however, the differences were less pronounced than for single antennas. Conclusions: Single- and dual-antenna arrays systems operating at 2.45 GHz yield larger ablation zone due to greater power deposition in proximity to the antenna, as well as greater role of thermal conduction.

  4. THE ATACAMA COSMOLOGY TELESCOPE: EXTRAGALACTIC SOURCES AT 148 GHz IN THE 2008 SURVEY

    We report on extragalactic sources detected in a 455 deg2 map of the southern sky made with data at a frequency of 148 GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15 mJy to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low-redshift X-ray-selected galaxy clusters. Estimates of the radio to millimeter-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50 mJy) 148 GHz selected sample with complete cross-identifications from the Australia Telescope 20 GHz survey, we observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of α5-20 = -0.07 ± 0.06, α20-148 = -0.39 ± 0.04, and α5-148 = -0.20 ± 0.03. When the measured spectral indices are taken into account, the 148 GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is C Sync = (2.8 ± 0.3) x 10-6μK2.

  5. Parsec-scale properties of GHz-Peaked Spectrum sources from 2.3 and 8.6 GHz VLBI surveys

    Sokolovsky, K V

    2009-01-01

    We investigate the sample of 213 GPS sources selected from simultaneous multi-frequency 1-22 GHz observations obtained with RATAN-600 radio telescope. We use publicly available data to characterize parsec-scale structure of the selected sources. Among them we found 121 core dominated sources, 76 Compact Symmetric Object (CSO) candidates (24 of them are highly probable), 16 sources have complex parsec-scale morphology. Most of GPS galaxies are characterized by CSO-type morphology and lower observed peak frequency (~1.8 GHz). Most of GPS quasars are characterized by "core-jet"-type morphology and higher observed peak frequency (~3.6 GHz). This is in good agreement with previous results. However, we found a number of sources for which the general relation CSO - galaxy, core-jet - quasar does not hold. These sources deserve detailed investigation. Assuming simple synchrotron model of a homogeneous cloud we estimate characteristic magnetic field in parsec-scale components of GPS sources to be B ~ 10 mG.

  6. The VLBA Imaging And Polarimetry Survey at 5 GHz

    Helmboldt, J.F.; Taylor, G.B.; Tremblay, S.; Fassnacht, C.D.; Walker, R.C.; Myers, S.T.; Sjouwerman, L.O.; Pearson, T.J.; Readhead, A.C.S.; Weintraub, L.; Gehrels, N.; Romani, R.W.; Healey, S.; Michelson, P.F.; Blandford, R.D.; Cotter, G.; /New Mexico U. /UC, Davis /NRAO, Socorro /Caltech /NASA, Goddard /Stanford U., Phys. Dept. /KIPAC, Menlo

    2006-11-20

    We present the first results of the VLBA Imaging and Polarimetry Survey (VIPS), a 5 GHz VLBI survey of 1,127 sources with flat radio spectra. Through automated data reduction and imaging routines, we have produced publicly available I, Q, and U images and have detected polarized flux density from 37% of the sources. We have also developed an algorithm to use each source's I image to automatically classify it as a point-like source, a core-jet, a compact symmetric object (CSO) candidate, or a complex source. Using data from the Sloan Digital Sky Survey (SDSS), we have found no significant trend between optical flux and 5 GHz flux density for any of the source categories. Using the velocity width of the H{beta} emission line and the monochromatic luminosity at 5100 to estimate the central black hole mass, M{sub BH}, we have found a weak trend between M{sub BH} and 5 GHz luminosity density for objects with SDSS spectra. Ongoing optical follow-up for all VIPS sources will allow for more detailed explorations of these issues. The mean ratio of the polarized to total 5 GHz flux density for VIPS sources with detected polarized flux density ranges from 1% to 20% with a median value of about 5%. This ratio is a factor of {approx}3 larger if only the jet components of core-jet systems are considered and is noticeably higher for relatively large core-jet systems than for other source types, regardless of which components (i.e., core, jet, or both) are considered. We have also found significant evidence that the directions of the jets in core-jet systems tend to be perpendicular to the electric vector position angles (EVPAs). The data is consistent with a scenario in which {approx}24% of the polarized core-jets have EVPAs that are anti-aligned with the directions of their jet components and which have a substantial amount of Faraday rotation. Follow-up observations at multiple frequencies will address this issue in more detail. In addition to these initial results, plans

  7. On-wafer de-embedding techniques from 0.1 to 110 GHz

    On-wafer S-parameter de-embedding techniques from 0.1 to 110 GHz are researched. The solving results of thru-reflect-line (TRL) and line-reflect-match (LRM) de-embedding algorithms, when the input and output ports are asymmetric, are given. The de-embedding standards of TRL and LRM are designed on an InP substrate. The validity of the de-embedding results is demonstrated through two passive components, and the accuracy of TRL and LRM de-embedding techniques is compared from 0.1 to 110 GHz. By utilizing an LRM technique in 0.1–40 GHz and a TRL technique in 75–110 GHz, the intrinsic S-parameters of active device HBT in two frequency bands are obtained, and comparisons of the extracted small-signal current gain and the unilateral power gain before and after de-embedding are presented. The whole S-parameters of actual DUT from 0.1 to 110 GHz can be obtained by interpolation. (paper)

  8. Multichannel frequency dividers using MSW

    Zavislyak, I. V.; Romanyuk, V. F.; Stakhursky, L. L.

    1997-01-01

    Multichannel frequency dividers (multiplexers) are obligatory elements of many radar and communication systems. They are first of all used when signal processing in the real time is needed within the band of several GHz [1].The frequency dividers using magnetostatic waves (MSW) and resonances (MSR) are perspective devices in spite of the problems connected with low termostability of their electric characteristics. The use of the epitaxial films of yttrium-iron garnet (YIG), barium ferrite (BF...

  9. Širokopásmová anténa pro pásmo od 5 GHz do 10 GHz

    Hebelka, Vladimír

    2009-01-01

    V této práci je popisován návrh a výroba širokopásmové motýlkové antény pro pásmo od 5GHz do 10GHz. První část se zabývá popisem typů motýlkových antén. Další části je uveden návrh motýlkových antén a jejich optimalizaci v programu CST microwave studio. V závěrečné části jsou porovnány výsledky dosažené v simulaci s výsledky naměřenými na vyrobených motýlkových anténách. The design and manufacturing of a wideband bow-tie antennas for the frequency range from 5GHz to 10GHz are described on ...

  10. Investigation of a 140 GHz gryo-backward wave oscillator and a 95 GHz gyro-traveling wave

    There is current interest in developing a high-power source of continuously tunable millimeter wave radiation as a RF driver for high-power gyrotron, CARM, or FEL amplifiers. The gyrotron backward wave oscillator is a voltage-tunable fast-wave device that can satisfy these requirements. This thesis reports on the design and experimental investigation of a 130--145 GHz gyrotron backward wave oscillator Novel operating features of this design include the use of a 80-kV, 6.2-A Pierce-wiggler electron beam source, a broadband motheye window and an overmoded TE1,2 cylindrical interaction waveguide. Although this device has demonstrated voltage-tunable operation over the design range in the TE1,2 mode, the frequency tuning is not continuous, output powers were low and full-beam transmission through the interaction region was not possible. Simulations indicate that the beam has very high velocity spread induced by space charge forces in the compression region. After increasing the diameter of the beam tunnel to achieve full transmission, the TE1,2 was not found. It is felt that the scraping off of the beam edge in the initial experiments allowed a better quality beam to enter the interaction region and inhibited coupling into competing forward wave modes. The need for radar systems with greater resolution has led to renewed interest in the development of efficient high-power amplifiers at 95 GHz. Current sources are limited to 6--8 kW of output power due to ohmic loading on the slow-wave circuit. A gyrotron traveling wave tube amplifier is capable of efficient operation over a wide bandwidth with the added attraction of low ohmic loading on the smooth fast-wave circuit. This thesis reports of the design a 95-GHz gyrotron traveling wave tube amplifier that is capable of high power (125 kW), high gain (38 dB), large bandwidth > 5 GHz and high efficiencies (> 30%)

  11. Feasibility studies for a wireless 60 GHz tracking detector readout

    Dittmeier, Sebastian; Soltveit, Hans Kristian; Wiedner, Dirk

    2016-01-01

    The amount of data produced by highly granular silicon tracking detectors in high energy physics experiments poses a major challenge to readout systems. At high collision rates, e.g. at LHC experiments, only a small fraction of data can be read out with currently used technologies. To cope with the requirements of future or upgraded experiments new data transfer techniques are required which offer high data rates at low power and low material budget. Wireless technologies operating in the 60 GHz band or at higher frequencies offer high data rates and are thus a promising upcoming alternative to conventional data transmission via electrical cables or optical fibers. Using wireless technology, the amount of cables and connectors in detectors can be significantly reduced. Tracking detectors profit most from a reduced material budget as fewer secondary particle interactions (multiple Coulomb scattering, energy loss, etc.) improve the tracking performance in general. We present feasibility studies regarding the in...

  12. High temperature heat treatment of 3 GHz niobium cavities

    We applied high temperature heat treatment to 3 GHz cavities to determine the preparation of niobium cavities using the titanium solid-state gettering process. Some preliminary results showed peak surface electric fields of up to 65 MV/m at a Q-factor of 2 x 1010. We evaluated improvement in the purity of the niobium by measuring the residual resistance ratio (RRR) at 10 K. The purest niobium we prepared reached a RRR of 670. To study the potential application to large-scale accelerator structures at lower frequencies, we are testing the possibility of heat treating the cavity half-cells before welding them. Therefore, we investigated the influence of electron beam welding on the RRR of high-purity niobium. In this paper we present the results of the investigations. (Author)3 figs., 2 tabs., 10 refs

  13. High temperature heat treatment of 3GHz niobium cavities

    We applied high temperature heat treatment to 3GHz cavities to determine the preparation of niobium cavities using the titanium solid-state gettering process. Some preliminary results showed peak surface electric fields of up to 65MV/m at a Q-factor of 2xlO10. We evaluated improvement in the purity of the niobium by measuring the residual resistance ratio (RRR) at 10K. The purest niobium we prepared reached a RRR of 670. To study the potential application to large-scale accelerator structures at lower frequencies, we are testing the possibility of heat treating the cavity half-cells before welding them. Therefore, we investigated the influence of electron beam welding on the RRR of high-purity niobium

  14. Quantum Cascade Laser Frequency Combs

    Faist, Jérôme; Villares, Gustavo; Scalari, Giacomo; Rösch, Markus; Bonzon, Christopher; Hugi, Andreas; Beck, Mattias

    2015-01-01

    It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100 mW and frequency coverage of 100 cm$^{-1}$ in the mid-infrared. In the THz range, 10 mW of average power and 600 GHz of frequency coverage are reported. As a result of th...

  15. A 94-GHz millimeter-wave sensor for speech signal acquisition.

    Li, Sheng; Tian, Ying; Lu, Guohua; Zhang, Yang; Lv, Hao; Yu, Xiao; Xue, Huijun; Zhang, Hua; Wang, Jianqi; Jing, Xijing

    2013-01-01

    High frequency millimeter-wave (MMW) radar-like sensors enable the detection of speech signals. This novel non-acoustic speech detection method has some special advantages not offered by traditional microphones, such as preventing strong-acoustic interference, high directional sensitivity with penetration, and long detection distance. A 94-GHz MMW radar sensor was employed in this study to test its speech acquisition ability. A 34-GHz zero intermediate frequency radar, a 34-GHz superheterodyne radar, and a microphone were also used for comparison purposes. A short-time phase-spectrum-compensation algorithm was used to enhance the detected speech. The results reveal that the 94-GHz radar sensor showed the highest sensitivity and obtained the highest speech quality subjective measurement score. This result suggests that the MMW radar sensor has better performance than a traditional microphone in terms of speech detection for detection distances longer than 1 m. As a substitute for the traditional speech acquisition method, this novel speech acquisition method demonstrates a large potential for many speech related applications. PMID:24284764

  16. A 94-GHz Millimeter-Wave Sensor for Speech Signal Acquisition

    Jianqi Wang

    2013-10-01

    Full Text Available High frequency millimeter-wave (MMW radar-like sensors enable the detection of speech signals. This novel non-acoustic speech detection method has some special advantages not offered by traditional microphones, such as preventing strong-acoustic interference, high directional sensitivity with penetration, and long detection distance. A 94-GHz MMW radar sensor was employed in this study to test its speech acquisition ability. A 34-GHz zero intermediate frequency radar, a 34-GHz superheterodyne radar, and a microphone were also used for comparison purposes. A short-time phase-spectrum-compensation algorithm was used to enhance the detected speech. The results reveal that the 94-GHz radar sensor showed the highest sensitivity and obtained the highest speech quality subjective measurement score. This result suggests that the MMW radar sensor has better performance than a traditional microphone in terms of speech detection for detection distances longer than 1 m. As a substitute for the traditional speech acquisition method, this novel speech acquisition method demonstrates a large potential for many speech related applications.

  17. Simultaneous measurements of atmospheric emissions at 10, 33 and 90 GHz

    As part of a larger experiment to measure the cosmic microwave background radiation spectrum, frequent simultaneous measurements of the microwave thermal emission from the earth's atmosphere were made at three fixed frequencies, namely, 10 GHz, 33 GHz and 90 GHz. We performed these measurements at two separate locations, Berkeley and White Mountain, which greatly differed in altitude and climatic conditions. Typical values measured in Berkeley of the atmospheric antenna temperature during good weather are 3.13 +- 0.300K, 12.3 +- 0.30K and 34.6 +- 0.50K, for 10, 33, and 90 GHz respectively. Corresponding values measured at White Mountain are 1.15 +- 0.10K, 4.51 +- 0.180K and 11.0 +- 0.20K. Because the measurements are simultaneous in nature, correlations between the measurements taken at the various frequencies provide constraints on models of the microwave emission of the earth's atmosphere, especially models describing atmospheric emission as a function of precipitable water content

  18. 300 GHz imaging with 8 meter stand-off distance and one-dimensional synthetic image reconstruction

    Keil, Andreas; Quast, Holger; Loeffler, Torsten;

    2011-01-01

    An active system for stand-off imaging operating in a frequency range from 234 GHz to 306 GHz is presented. Imaging is achieved by combining a line array consisting of 8 emitters and 16 detectors with a scanning cylindrical mirror system. A stand-off distance of 7-8 m is achieved using a system...... of mirrors with effective aperture of 0.5 × 0.5 meter. Information about range and reflectivity of the object are obtained using an active FMCW (frequency modulated continuous wave) radar operation principle. Data acquisition time for one line is as short as 1 ms. Synthetic image reconstruction is achieved...

  19. 25 GHz methanol masers in regions of massive star formation

    Britton, Tui R.; Voronkov, Maxim A.

    2012-07-01

    The bright 25 GHz series of methanol masers is formed in highly energetic regions of massive star formation and provides a natural signpost of shocked gas surrounding newly forming stars. A systematic survey for the 25 GHz masers has only recently been carried out. We present the preliminary results from the interferometric follow up of 51 masers at 25 GHz in the southern sky.

  20. Multiple teleportation via partially entangled GHZ state

    Xiong, Pei-Ying; Yu, Xu-Tao; Zhan, Hai-Tao; Zhang, Zai-Chen

    2016-08-01

    Quantum teleportation is important for quantum communication. We propose a protocol that uses a partially entangled Greenberger-Horne-Zeilinger (GHZ) state for single hop teleportation. Quantum teleportation will succeed if the sender makes a Bell state measurement, and the receiver performs the Hadamard gate operation, applies appropriate Pauli operators, introduces an auxiliary particle, and applies the corresponding unitary matrix to recover the transmitted state.We also present a protocol to realize multiple teleportation of partially entangled GHZ state without an auxiliary particle. We show that the success probability of the teleportation is always 0 when the number of teleportations is odd. In order to improve the success probability of a multihop, we introduce the method used in our single hop teleportation, thus proposing a multiple teleportation protocol using auxiliary particles and a unitary matrix. The final success probability is shown to be improved significantly for the method without auxiliary particles for both an odd or even number of teleportations.

  1. Optoelectronic time-domain characterization of a 100 GHz sampling oscilloscope

    We have carried out an optoelectronic measurement of the impulse response of an ultrafast sampling oscilloscope with a nominal bandwidth of 100 GHz within a time window of approximately 100 ps. Our experimental technique also considers frequency components above the cut-off frequency of higher order modes of the 1.0 mm coaxial line, which is shown to be important for the specification of the impulse response of ultrafast sampling oscilloscopes. Additionally, we have measured the reflection coefficient of the sampling head induced by the mismatch of the sampling circuit and the coaxial connector which is larger than 0.5 for certain frequencies. The uncertainty analysis has been performed using the Monte Carlo method of Supplement 1 to the 'Guide to the Expression of Uncertainty in Measurement' and correlations in the estimated impulse response have been determined. Our measurements extend previous work which deals with the characterization of 70 GHz oscilloscopes and the measurement of 100 GHz oscilloscopes up to the cut-off frequency of higher order modes

  2. Micromachined Horn Antenna Operating at 75 GHz

    Grzegorczyk, Tomasz M.; Zurcher, Jean-François; Renaud, Philippe; Mosig, Juan R.

    2000-01-01

    We propose in this paper an integrated cavity-backed horn antenna, generalizing the well-known SSFIP (Strip-Slot-Foam-Inverted Patch) design, operating at 75 GHz. The antenna was optimized using a full-wave software and realized using micromachining technologies. The proposed structure can be used for high radiation ef-ficiency antennas and arrays in the millimeter-wave band, since surface waves are inherently suppressed by the use of a metallic horn and a cavity configuration.

  3. Results of 170 GHz gyrotron tests

    During the last few years the development of 170 GHz gyrotron for ITER have been under way. Sketchy description of experiment and test results of an improved design gyrotron with a depressed collector, are reported. The analysis of the phenomena causing the destruction of the output window is submitted. The projects for the following experiments are presented. The new 170 GHz/1 MW/50%/CW gyrotron with depressed collector and CVD diamond window was developed by GYCOM. This gyrotron was tested with BN window and then with diamond window. The gyrotron testing showed that practically all ITER requirements are satisfied except of pulse duration limited to that time by brick load arcing. Imperfection of arc protection system gave the possibility for arc-plasma to come to the window and destroy it. New loads have been created and tested at 140 GHz, with output gyrotron power Phf = 820 kW and the pulse duration T = 3.5 s. A new version of protection system has been developed and tested in experiment. The next gyrotron with modified electron gun has been manufactured. After first stage test, BN window will be replaced with new CVD diamond unit, which is assembling now. Testing of this gyrotron is planned to carry out in May 2002. (authors)

  4. Broadband continuously frequency tunable gyrotron for 600 MHz DNP-NMR spectroscopy

    A broadband continuously frequency tunable gyrotron with a triode-type magnetron injection gun was developed as power source for analysis of protein structures. The TE7,3 oscillation mode was selected to avoid mode competitions in the high magnetic field side. Axial modes of the TE7,3,-10 were sequentially excited by changing the cavity magnetic field, and frequency tuning of about 4 GHz around 395 GHz was observed with output power greater than 50 W. The frequency also varied about 1 GHz as the anode-cathode voltage varied. Thus, the broadest tuning bandwidth in the 400 GHz band gyrotrons was achieved. (author)

  5. Z45: A new 45-GHz band dual-polarization HEMT receiver for the NRO 45-m radio telescope

    Nakamura, Fumitaka; Ogawa, Hideo; Yonekura, Yoshinori; Kimura, Kimihiko; Okada, Nozomi; Kozu, Minato; Hasegawa, Yutaka; Tokuda, Kazuki; Ochiai, Tetsu; Mizuno, Izumi; Dobashi, Kazuhito; Shimoikura, Tomomi; Kameno, Seiji; Taniguchi, Kotomi; Shinnaga, Hiroko; Takano, Shuro; Kawabe, Ryohei; Nakajima, Taku; Iono, Daisuke; Kuno, Nario; Onishi, Toshikazu; Momose, Munetake; Yamamoto, Satoshi

    2015-12-01

    We developed a dual-linear-polarization HEMT (High Electron Mobility Transistor) amplifier receiver system of the 45-GHz band (hereafter Z45), and installed it in the Nobeyama 45-m radio telescope. The receiver system is designed to conduct polarization observations by taking the cross-correlation of two linearly polarized components, from which we process full Stokes spectroscopy. We aim to measure the magnetic field strength through the Zeeman effect of the emission line of CCS (JN = 43-32) toward pre-protostellar cores. A linear-polarization receiver system has a smaller contribution of instrumental polarization components to the Stokes V spectra than that of the circular polarization system, so that it is easier to obtain the Stokes V spectra. The receiver has an RF frequency of 42-46 GHz and an intermediate frequency (IF) band of 4-8 GHz. The typical noise temperature is about 50 K, and the system noise temperature ranges from 100 to 150 K over the frequency of 42-46 GHz. The receiver system is connected to two spectrometers, SAM45 and PolariS. SAM45 is a highly flexible FX-type digital spectrometer with a finest frequency resolution of 3.81 kHz. PolariS is a newly developed digital spectrometer with a finest frequency resolution of 60 Hz, and which has a capability to process the full-Stokes spectroscopy. The half-power beam width (HPBW) was measured to be 37″ at 43 GHz. The main beam efficiency of the Gaussian main beam was derived to be 0.72 at 43 GHz. The SiO maser observations show that the beam pattern is reasonably round at about 10% of the peak intensity and the side-lobe level was less than 3% of the peak intensity. Finally, we present some examples of astronomical observations using Z45.

  6. The 6.7-GHz and 25-GHz methanol masers in OMC-1

    Voronkov, M A; Ellingsen, S P; Ostrovskii, A B

    2005-01-01

    The Australia Telescope Compact Array (ATCA) has been used to search for methanol maser emission at 6.7 GHz towards OMC-1. Two features peaking at 7.2 km/s and -1.1 km/s have been detected. The former has at least two components close in both velocity and position. It is located south-east of the Orion Kleinmann-Low (Orion-KL) nebula in the region of outflow traced by the 25-GHz methanol masers and the 95-GHz methanol emission. It is shown by modelling that in contrast to the widespread opinion that simultaneous masing of methanol transitions of different classes is impossible there are conditions for which simultaneous masing of the class II transition at 6.7-GHz and some class I transitions (e.g. the series at 25 GHz) is possible. A relevant example is provided, in which the pumping occurs via the first torsionally excited state and is driven by radiation of the dust intermixed with the gas in the cloud. In this regime the dust temperature is significantly lower (T is about 60 K) than in the case of bright ...

  7. Broadband antenna with frequency scanning

    A. A. Shekaturin

    2014-06-01

    Full Text Available Relevance of this study. The main advantage of frequency scanning is simplicity of implementation. At this point, multifunctional usage of microwave modules is an urgent task, as well as their maximum simpler and cheaper. Antenna design and operation. The study is aimed at providing electric antenna with frequency scanning. It was based on the log-periodic antenna due to its wideband and negotiation capability over the entire operating frequency range. For this distribution line is bent in an arc of a circle in a plane blade while vibrators are arranged along the radius. Computer modeling of antennas with frequency scanning. Modeled with a non-mechanical motion antenna beam emitters representing system for receiving a radio frequency signal on mobile objects calculated for 1.8 GHz ... 4.2 GHz. The simulation was performed in a software environment for numerical modeling of electromagnetic «Feko 5.5». Analysis of the interaction of radiation is based on the method of moments. Findings. The result of this work is to propose a new design of the antenna with a frequency scanning method as agreed in a wide frequency range. In the studied technical solution provided by the rotation of NAM in the frequency range, and the matching of the antenna to the feed line is maintained. Application of this type of antennas on the proposed technical solution in communication systems will improve the communication reliability by maintaining coordination in the frequency range

  8. A high-gradient test of a 30 GHz copper accelerating structure

    Corsini, Roberto; Fandos, Raquel; Grudiev, Alexei; Jensen, Erk; Mete, Oznur; Ramsvik, Trond; Rodríguez, José Alberto; Sladen, Jonathan P H; Syratchev, Igor V; Taborelli, Mauro; Tecker, Frank A; Urschütz, Peter; Wilson, Ian H; Wuensch, Walter

    2006-01-01

    The CLIC study is investigating a number of different materials at different frequencies in order to find ways to increase achievable accelerating gradient and to understand what are the important parameters for high-gradient operation. So far a series of rf tests have been made with a set of identical-geometry 30 GHz and X-band structures in copper, tungsten and molybdenum. A new test of a 30 GHz copper accelerating structure has been completed in CTF3 with pulse lengths up to 70 ns. The new results are presented and compared to the previous structures to determine dependencies of quantities such accelerating gradient, material, frequency, pulse length, conditioning rate, breakdown rate and surface damage.

  9. Realization of a 33 GHz phononic crystal fabricated in a freestanding membrane

    Drew F. Goettler

    2011-12-01

    Full Text Available Phononic crystals (PnCs are man-made structures with periodically varying material properties such as density, ρ, and elastic modulus, E. Periodic variations of the material properties with nanoscale characteristic dimensions yield PnCs that operate at frequencies above 10 GHz, allowing for the manipulation of thermal properties. In this article, a 2D simple cubic lattice PnC operating at 33 GHz is reported. The PnC is created by nanofabrication with a focused ion beam. A freestanding membrane of silicon is ion milled to create a simple cubic array of 32 nm diameter holes that are subsequently backfilled with tungsten to create inclusions at a spacing of 100 nm. Simulations are used to predict the operating frequency of the PnC. Additional modeling shows that milling a freestanding membrane has a unique characteristic; the exit via has a conical shape, or trumpet-like appearance.

  10. A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

    M. M. Islam

    2014-01-01

    Full Text Available A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band.

  11. Vegetation and soil backscatter over the 4-18 GHz region

    Ulaby, F. T.

    1974-01-01

    Using an FM-CW radar mounted atop a truck-mounted boom, 4-8 GHz backscatter spectral data was gathered during the 1972 growing season at incidence angles of 0-70 deg in 10 deg steps for each of the four linear polarization combinations. The data covers four mature crop types (corn, milo, soybeans and alfalfa) and bare ground taken under a wide range of soil and plant moisture contents. To insure statistical representation of the results, measurements were conducted over 147 fields corresponding to a total of about 50,000 data points. During 1973, a higher frequency version of the above system was used to collect additional data over the 8-18 GHz frequency region. This paper presents a summary of the results and suggests design criteria for future radar remote sensing missions.

  12. 60 GHz OCS mm-wave generation for ROF system based on saturated parametric amplification effect in HNLF

    LI Wen-jing; SANG Xin-zhu; YUAN Jin-hui; WANG Kui-ru; YU Chong-xiu; XIN Xiang-jun

    2010-01-01

    @@ A novel approach to generate 60 GHz optical carrier suppression(OCS)millimeter-wave(mm-wave)signal based on the saturated optical parametric amplification(OPA)effect in high non-linear fiber(HNLF)is investigated.In the proposed system,the OPA effect occurs when the signal and pump with 30 GHz frequency interval are set into the high non-linear fiber.By controlling the length of HNLF,OPA effect saturates,and the pump power is delivered in a large extent to the signal and idler light,so a 60 GHz OCS ram-wave is generated.The system does not need high-speed external modulator,high-frequency vibration source or narrow-band filter,which greatly reduces the cost and improves the stability of the radio over fiber(ROF)system.Results show that the 10 Gb/s downstream signal can be transmitted with negligible power penalty.

  13. Design of a high power, 10 GHz auto-resonant peniotron amplifier

    The autoresonant peniotron amplifier is a suitable source of high power RF radiation because of its high gain, high power, high frequency and high efficiency operation features. In this report we present our simulation results of a 10 GHz, 2.2 GW autoresonant peniotron amplifier with an electron energy conversion efficiency of 72.5 % and a gain of about 58 dB. (author)

  14. How To Monitor AGN Intra-Day Variability at 230 GHz

    Kim, Jae-Young; Trippe, Sascha

    2013-01-01

    We probe the feasibility of high-frequency radio observations of very rapid flux variations in compact active galactic nuclei (AGN). Our study assumes observations at 230 GHz with a small 6-meter class observatory, using the SNU Radio Astronomical Observatory (SRAO) as example. We find that 33 radio-bright sources are observable with signal-to-noise ratios larger than ten. We derive statistical detection limits via exhaustive Monte Carlo simulations assuming (a) periodic, and (b) episodic fla...

  15. Dynamic nuclear polarization enhanced NMR at 187 GHz/284 MHz using an extended interaction Klystron amplifier

    Watts, A; Kemp, T; Dannatt, HRW; Barrow, NS; Brown, SP; Newton, ME; Dupree, R.

    2016-01-01

    A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer which uses a 187 GHz (corresponding to 1H NMR frequency of 284 MHz) Extended Interaction Klystron (EIK) amplifier as the microwave source is briefly described. Its performance is demonstrated for a biomolecule (bacteriorhodopsin), a pharmaceutical, and surface functionalised silica. The EIK is very compact and easily incorporated into an existing spectrometer. The bandwidth of the amplifier i...

  16. The GBT 67 -- 93.6 GHz Spectral Line Survey of Orion-KL

    Frayer, D T; Meijer, M; Hough, L; White, S; Norrod, R; Watts, G; Stennes, M; Simon, R; Woody, D; Srikanth, S; Pospieszalski, M; Bryerton, E; Whitehead, M; Ford, P; Mello, M; Bloss, M

    2015-01-01

    We present a 67--93.6 GHz spectral line survey of Orion-KL with the new 4 mm Receiver on the Green Bank Telescope (GBT). The survey reaches unprecedented depths and covers the low-frequency end of the 3 mm atmospheric window which has been relatively unexplored previously. The entire spectral-line survey is published electronically for general use by the astronomical community. The calibration and performance of 4 mm Receiver on the GBT is also summarized.

  17. Q-Band (37-41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Simmons, Rainee N.; Wintucky, Edwin G.

    2012-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37-41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cut-paraboloidal reflector.

  18. Q-Band (37 to 41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Simons, Rainee N.; Wintucky, Edwin G.

    2014-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37 to 41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cutparaboloidal reflector.

  19. 5-6 GHz RFIC Front-End Components in Silicon Germanium HBT Technology

    Johnson, Daniel Austin

    2001-01-01

    In 1997 the Federal Communications Commission (FCC) released 300 MHz of spectrum between 5-6 GHz designated the unlicensed national information infrastructure (U-NII) band. The intention of the FCC was to provide an unlicensed band of frequencies that would enable high-speed wireless local area networks (WLANs) and facilitate wireless access to the national information infrastructure with a minimum interference to other devices. Currently, there is a lack of cost-effective...

  20. Latest Results from the 4.8 GHz LHC Schottky System

    Favier, M

    2012-01-01

    This paper will present the latest results from the LHC 4.8 GHz travelling wave schottky system, summarising measurements performed with both lead ions and protons during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies.

  1. Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck

    B. Partridge; López-Caniego, M.; Perley, R. A.; Stevens, J.; Butler, B. J.; Rocha, G.; Walter, B; Zacchei, A.

    2015-01-01

    The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite's annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus Planck's flux density measurements of compact sources are absolute in the same sense. We have made coordinated VLA and ATCA observations of 65 strong, unresolv...

  2. Performance and operation of advanced superconducting electron cyclotron resonance ion source SECRAL at 24 GHz.

    Zhao, H W; Lu, W; Zhang, X Z; Feng, Y C; Guo, J W; Cao, Y; Li, J Y; Guo, X H; Sha, S; Sun, L T; Xie, D Z

    2012-02-01

    SECRAL (superconducting ECR ion source with advanced design in Lanzhou) ion source has been in routine operation for Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex since May 2007. To further enhance the SECRAL performance in order to satisfy the increasing demand for intensive highly charged ion beams, 3-5 kW high power 24 GHz single frequency and 24 GHz +18 GHz double frequency with an aluminum plasma chamber were tested, and some exciting results were produced with quite a few new record highly charged ion beam intensities, such as (129)Xe(35+) of 64 eμA, (129)Xe(42+) of 3 eμA, (209)Bi(41+) of 50 eμA, (209)Bi(50+) of 4.3 eμA and (209)Bi(54+) of 0.2 eμA. In most cases SECRAL is operated at 18 GHz to deliver highly charged heavy ion beams for the HIRFL accelerator, only for those very high charge states and very heavy ion beams such as (209)Bi(36+) and (209)Bi(41+), SECRAL has been operated at 24 GHz. The total operation beam time provided by SECRAL up to July 2011 has exceeded 7720 hours. In this paper, the latest performance, development, and operation status of SECRAL ion source are presented. The latest results and reliable long-term operation for the HIRFL accelerator have demonstrated that SECRAL performance for production of highly charged heavy ion beams remains improving at higher RF power with optimized tuning. PMID:22380167

  3. Yagi-Uda Antenna For L-Band Frequency Range

    Gulshan Sharma; Anand N. Sharma; Ashish Duvey; P. K. Singhal

    2012-01-01

    A yagi-uda antenna for L-band (1-   2GHz) frequency range is presented. The designing formulas and related antenna characteristics such as return loss, radiation pattern and gain were also discussed in this paper.

  4. Novel Radio Architectures for UWB, 60 GHz, and Cognitive Wireless Systems

    Cabric Danijela

    2006-01-01

    Full Text Available There are several new radio systems which exploit novel strategies being made possible by the regulatory agencies to increase the availability of spectrum for wireless applications. Three of these that will be discussed are ultra-wideband (UWB, 60 GHz, and cognitive radios. The UWB approach attempts to share the spectrum with higher-priority users by transmitting at power levels that are so low that they do not cause interference. On the other hand, cognitive radios attempt to share spectra by introducing a spectrum sensing function, so that they are able to transmit in unused portions at a given time, place, and frequency. Another approach is to exploit the advances in CMOS technology to operate in frequency bands in the millimeter-wave region. 60 GHz operation is particularly attractive because of the 7 GHz of unlicensed spectrum that has been made available there. In this paper, we present an overview of novel radio architecture design approaches and address challenges dealing with high-frequencies, wide-bandwidths, and large dynamic-range signals encountered in these future wireless systems.

  5. Bi-layer Kinetic Inductance Detectors for space observations between 80-120 GHz

    Catalano, A; Sueur, H le; Benoit, A; Bourrion, O; Calvo, M; Dumoulin, L; Levy-Bertrand, F; Macìas-Pérez, J; Marnieros, S; Ponthieu, N; Monfardini, A

    2015-01-01

    We have developed Lumped Element Kinetic Inductance Detectors (LEKID) sensitive in the frequency band from 80 to 120~GHz. In this work, we take advantage of the so-called proximity effect to reduce the superconducting gap of Aluminium, otherwise strongly suppressing the LEKID response for frequencies smaller than 100~GHz. We have designed, produced and optically tested various fully multiplexed arrays based on multi-layers combinations of Aluminium (Al) and Titanium (Ti). Their sensitivities have been measured using a dedicated closed-circle 100 mK dilution cryostat and a sky simulator allowing to reproduce realistic observation conditions. The spectral response has been characterised with a Martin-Puplett interferometer up to THz frequencies, and with a resolution of 3~GHz. We demonstrate that Ti-Al LEKID can reach an optical sensitivity of about $1.4$ $10^{-17}$~$W/Hz^{0.5}$ (best pixel), or $2.2$ $10^{-17}$~$W/Hz^{0.5}$ when averaged over the whole array. The optical background was set to roughly 0.4~pW pe...

  6. Summary and analysis of 216 GHz polarimetric measurements of in-situ rain

    Hedden, Abigail S.; Wikner, David A.; Bradley, Russell W.

    2015-05-01

    The Army Research Laboratory (ARL) has developed a polarimetric frequency-modulated continuous-wave (FMCW) instrumentation radar that has been used to study the polarization and backscatter properties of in-situ rain in the 220 GHz atmospheric window. A summary of the preliminary measurements is presented in this work including an analysis of the co-polarization backscatter and attenuation characteristics measured at 216 GHz. A marginal detection of the copolarization backscatter signature of rain was made during a series of fast-moving, heavy downpour thunderstorm events. A detection limit of -40±3 dB[m2/m3] was found for the VV-polarization cross section per unit volume for rain rates up to 150 mm/hr. Co-polarization (VV- and HH-polarization) attenuation characteristics measured at high rain rates (< 20 mm/hr) were well described by a Joss thunderstorm drop distribution in the high frequency limit, where drop size is much greater than the observation wavelength. Observations at 216 GHz suggest attenuation levels of 8-10 dB/km at rain rates above 20 mm/hr, strengthening previous evidence that attenuation through rain is independent of frequency under high rain rate conditions. Attenuation measurements at lower rain rates (< 20 mm/hr) were qualitatively consistent with both Laws and Parsons and Joss thunderstorm distributions.

  7. Dielectric Resonator Antenna Mounted on Cylindrical Ground Plane for Handheld RFID Reader at 5.8 GHz

    Hend Abd El-Azem Malhat

    2012-10-01

    Full Text Available Dielectric resonator antenna (DRA mounted on cylindrical ground plane is investigated for handheld RFID reader applications at 5.8 GHz. The simplicity of the structure makes it practical in terms of cost, space, and ease of fabrication. The radiation characteristics of the antenna in free space and in the presence of a proposed compact reader device model and human hand are calculated. The antenna is circularly polarized and exhibits peak gain of 7.62 dB at 5.8 GHz with high front to back ratio of 15.5 dB. Using the same reader device model, a sequentially feeding 2×2 DRA array mounted on the same cylindrical ground plane is used for RFID reader antenna at 5.8 GHz. The array introduces high gain of 9.36 dB at 5.8 GHz with high front to back ratio of 10.48 dB. The 2×2 DRA array elements exhibit circular polarization over a frequency band of 1.1 GHz. The axial ratio is 1.1 dB at 5.8 GHz. The proposed reader model is simple and has a small size compared with that in the case of planar ground plane. The results are calculated using the finite element method (FEM and compared with that calculated using the finite integral technique (FIT.

  8. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser Project

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  9. The 8-18 GHz radar spectrometer

    Bush, T. F.; Ulaby, F. T.

    1973-01-01

    The design, construction, testing, and accuracy of an 8-18 GHz radar spectrometer, an FM-CW system which employs a dual antenna system, is described. The antennas, transmitter, and a portion of the receiver are mounted at the top of a 26 meter hydraulic boom which is in turn mounted on a truck for system mobility. HH and VV polarized measurements are possible at incidence angles ranging from 0 deg. to 80 deg. Calibration is accomplished by referencing the measurements against a Luneberg lens of known radar cross section.

  10. Force detected electron spin resonance at 94 GHz.

    Cruickshank, Paul A S; Smith, Graham M

    2007-01-01

    Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins, and it offers both extremely high absolute sensitivity and high spatial imaging resolution. However, compared to conventional induction mode ESR the technique also has a comparatively poor concentration sensitivity and it introduces complications in interpreting and combining both spectroscopy and imaging. One method to improve both sensitivity and spectral resolution is to operate in high magnetic fields in order to increase the sample magnetization and g-factor resolution. In this article we present FDESR measurements on the organic conductor (fluoranthene)(2)PF(6) at 3.2 T, with a corresponding millimeter-wave frequency of 93.5 GHz, which we believe are the highest field results for FDESR reported in the literature to date. A magnet-on-cantilever approach was used, with a high-anisotropy microwave ferrite as the gradient source and employing cyclic saturation to modulate the magnetization at the cantilever fundamental frequency. PMID:17503940

  11. The milliarcsecond structure of 3C 273 at 22 GHz

    The first VLBI images at 22 GHz of the jet in the quasar 3C 273 are presented. In addition to the compact core region, two emission regions can be identified with features seen at lower frequencies; they separate from the core with constant speeds of 0.65 + or - 0.09 and 0.92 + or - 0.11 mas/yr, corresponding to apparent superluminal motion of 4.3 + or - 0.3c and 6.1 + or - 0.3c (for Ho = 100 km/s Mpc, qo = 0.5). The core region brightened at about the estimated epoch of zero separation for the latest superluminal component, suggesting a causal relationship. The curved ridge line of the jet smoothly extends inward towards the core, although no pronounced bends in the range of core distance 0.5-2.5 mas are seen. No significant evidence is found against a common path of subsequent superluminal features. An apparent frequency dependence in the position of one superluminal feature tentatively suggests that opacity effects across the jet direction are present. The results are consistent with an interpretation of the superluminal features as shocks in an underlying relativistic flow, although alternative explanations cannot be ruled out. 43 refs

  12. The milliarcsecond structure of 3C 273 at 22 GHz

    Zensus, J.A.; Biretta, J.A.; Unwin, S.C.; Cohen, M.H. (National Radio Astronomy Observatory, Socorro, NM (USA) Owens Valley Radio Observatory, Pasadena, CA (USA))

    1990-12-01

    The first VLBI images at 22 GHz of the jet in the quasar 3C 273 are presented. In addition to the compact core region, two emission regions can be identified with features seen at lower frequencies; they separate from the core with constant speeds of 0.65 + or - 0.09 and 0.92 + or - 0.11 mas/yr, corresponding to apparent superluminal motion of 4.3 + or - 0.3c and 6.1 + or - 0.3c (for Ho = 100 km/s Mpc, qo = 0.5). The core region brightened at about the estimated epoch of zero separation for the latest superluminal component, suggesting a causal relationship. The curved ridge line of the jet smoothly extends inward towards the core, although no pronounced bends in the range of core distance 0.5-2.5 mas are seen. No significant evidence is found against a common path of subsequent superluminal features. An apparent frequency dependence in the position of one superluminal feature tentatively suggests that opacity effects across the jet direction are present. The results are consistent with an interpretation of the superluminal features as shocks in an underlying relativistic flow, although alternative explanations cannot be ruled out. 43 refs.

  13. The relationship between radio power at 22 and 43 GHz and black hole properties of AGN in elliptical galaxies

    Park, Songyoun; Sohn, Bong Won; Yi, Sukyoung K.

    2013-12-01

    We investigate the relationship between radio power and properties related to active galactic nuclei (AGNs). Radio power at 1.4 or 5 GHz, which has been used in many studies, can be affected by synchrotron self-absorption and free-free absorption in a dense region. On the other hand, these absorption effects get smaller at higher frequencies. Thus, we performed simultaneous observations at 22 and 43 GHz using the Korean VLBI Network (KVN) radio telescope based on a sample of 305 AGN candidates residing in elliptical galaxies from the overlap between the Sloan Digital Sky Survey (SDSS) Data Release 7 and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST). About 37% and 22% of the galaxies are detected at 22 and 43 GHz, respectively. Assuming no flux variability between the FIRST and KVN observations, spectral indices were derived from FIRST and KVN data and we found that over 70% of the detected galaxies have flat or inverted spectra, implying the presence of optically thick compact regions near the centres of the galaxies. Core radio power does not show a clear dependence on black hole mass at either low (1.4 GHz) or high (22 and 43 GHz) frequencies. However, we found that the luminosity of the [OIII] λ5007 emission line and the Eddington ratio correlate with radio power more closely at high frequencies than at low frequencies. This suggests that radio observation at high frequencies can be an appropriate tool for unveiling the innermost region. In addition, the luminosity of the [OIII] λ5007 emission line and the Eddington ratio can be used as a tracer of AGN activity. Our study suggests a causal connection between high frequency radio power and optical properties of AGNs. Table 5 is available in electronic form at http://www.aanda.org

  14. OCRA-p observations of the CRATES sources at 30 GHz

    Peel, M W; Battye, R A; Birkinshaw, M; Browne, I W A; Davis, R J; Feiler, R; Kus, A J; Lancaster, K; Lowe, S R; Pazderska, B M; Pazderski, E; Roukema, B F; Wilkinson, P N

    2010-01-01

    Knowledge of the population of radio sources in the range ~2-200 GHz is important for understanding their effects on measurements of the Cosmic Microwave Background power spectrum. We report measurements of the 30 GHz flux densities of 605 radio sources from the Combined Radio All-sky Targeted Eight-GHz Survey (CRATES), which have been made with the One Centimetre Receiver Array prototype (OCRA-p) on the Torun 32-m telescope. The flux densities of sources that were also observed by WMAP and previous OCRA surveys are in broad agreement with those reported here, however a number of sources display intrinsic variability. We find a good correlation between the 30 GHz and Fermi gamma-ray flux densities for common sources. We examine the radio spectra of all observed sources and report a number of Gigahertz-peaked and inverted spectrum sources. These measurements will be useful for comparison to those from the Low Frequency Instrument of the Planck satellite, which will make some of its most sensitive observations ...

  15. Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck

    Partridge, B.; López-Caniego, M.; Perley, R. A.; Stevens, J.; Butler, B. J.; Rocha, G.; Walter, B.; Zacchei, A.

    2016-04-01

    The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite’s annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus, Planck's flux density measurements of compact sources are absolute in the same sense. We have made coordinated Very Large Array (VLA) and Australia Telescope Compact Array (ATCA) observations of 65 strong, unresolved Planck sources in order to transfer Planck's calibration to ground-based instruments at 22, 28, and 43 GHz. The results are compared to microwave flux density scales currently based on planetary observations. Despite the scatter introduced by the variability of many of the sources, the flux density scales are determined to 1%–2% accuracy. At 28 GHz, the flux density scale used by the VLA runs 2%–3% ± 1.0% below Planck values with an uncertainty of +/- 1.0%; at 43 GHz, the discrepancy increases to 5%–6% ± 1.4% for both ATCA and the VLA.

  16. Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck

    Partridge, B; Perley, R A; Stevens, J; Butler, B J; Rocha, G; Walter, B; Zacchei, A

    2015-01-01

    The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite's annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus Planck's flux density measurements of compact sources are absolute in the same sense. We have made coordinated VLA and ATCA observations of 65 strong, unresolved Planck sources in order to transfer Planck's calibration to ground-based instruments at 22, 28, and 43 GHz. The results are compared to microwave flux density scales currently based on planetary observations. Despite the scatter introduced by the variability of many of the sources, the flux density scales are determined to 1-2% accuracy. At 28 GHz, the flux density scale used by the VLA runs 3.6% +- 1.0% below Planck values; at 43 GHz, the discrepancy increases to 6.2% +- 1.4% for both ATCA and the VLA.

  17. Commissioning of 170 GHz, 1 MW EC H&CD in KSTAR

    Oda Y.

    2012-09-01

    Full Text Available The newly installed electron cyclotron heating and current drive (EC H&CD system with a frequency of 170 GHz was successfully commissioned and used for the second-harmonic ECH-assisted startup in 2011 operational campaign of the KSTAR. As a RF power source, ITER pre-prototype of 170 GHz, 1 MW continuous-wave gyrotron, is loaned from the Japan Atomic Energy Agency (JAEA. During the KSTAR 2011 plamma campaign, maxumum pulse length of 10 sec at 0.6 MW EC beam was reliably injected into the plasma and the 170 GHz second harmonic ECH-assisted start-up was successful leading to reduce the flux consumption at toroidal magnetic field of 3 T. As a result, the flux consumption until the plasma current flat-top was reduced from 4.13 Wb for pure Ohmic to 3.62 Wb (12 % reduction for the perpendicular injection. When the EC beam is launched with toroidal angle of 20 deg in co-CD direction, more reduced magnetic flux consumption was obtained with 3.14 Wb (24 % reduction compared with pure OH plasmas. In recent, the gyrotron has been successfully commissioned with the output power of 1 MW and the pulse duration of 20 sec in KSTAR. This paper presents successful commissioning of 170 GHz EC H&CD system in KSTAR as well as the heating and startup experimental results.

  18. Multigigabit W-Band (75–110 GHz) Bidirectional Hybrid Fiber-Wireless Systems in Access Networks

    Pang, Xiaodan; Lebedev, Alexander; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2014-01-01

    We experimentally demonstrate multigigabit capacity bidirectional hybrid fiber-wireless systems with RF carrier frequencies at the W-band (75-110 GHz) that enables the seamless convergence between wireless and fiber-optic data transmission systems in access networks. In this study, we evaluate the...

  19. Experimental characterization of a hybrid fiber-wireless transmission link in the 75 to 110 GHz band

    Pang, Xiaodan; Yu, Xianbin; Zhao, Ying; Deng, Lei; Zibar, Darko; Tafur Monroy, Idelfonso

    2012-01-01

    We present a detailed experimental investigation of a hybrid optical-fiber wireless communication system operating at the 75 to 110 GHz (W-band) for meeting the emerging demands in short-range wireless applications. Measured W-band wireless channel properties such as channel loss, frequency...

  20. Application of band-stop filters for the 30-200 GHz range in oversized microwave systems

    van der Meiden, H. J.

    1999-01-01

    A simple and cheap method has been developed to prepare band-stop filters for the frequency region 30-200 GHz with a typical attenuation in the stop band of more than 27 dB. This filter consists of periodic metallic structures deposited on a thin substrate. The preparation is achieved by applying a

  1. Subharmonic energy gap structure in the Josephson radiation at 35 GHz from a superconducting thin-film microbridge

    Hansen, Jørn Bindslev; Levinsen, M. T.; Lindelof, Poul Erik; Dueholm, B.; Mygind, Jesper; Pedersen, Niels Falsig; Sørensen, O. H.

    1979-01-01

    Nonresonant detection of the Josephson radiation 35 GHz from a superconducting thin-film microbridge is reported. The high frequency and the accuracy of these measurements lead to a new important observation: subharmonic energy gap structure in the detected integral power. The maximum integral...

  2. Generation of 40 GHz CW soliton trains using multisoliton compression and transformation in a dispersion varying fiber

    Shipulin, A.V.; Dianov, E. M.; Richardson, D J; Payne, D. N.

    1994-01-01

    We experimentally demonstrated 40 GHz optical double-frequency beat-signal to soliton train transformation employing a novel technique based on multisoliton compression effecting a dispersion varying optical fibers. The quality of the generated pulses was approved by the following propagation in a fiber with the constant dispersion.

  3. Analysis of single pulse radio flux measurements of PSR B1133+16 at 4.85 and 8.35 GHz

    Krzeszowski, K; Słowikowska, A; Dyks, J; Jessner, A

    2014-01-01

    We show the results of microsecond resolution radio data analysis focused on flux measurements of single pulses of PSR~B1133+16. The data were recorded at 4.85 GHz and 8.35 GHz with 0.5 GHz and 1.1 GHz bandwidth, respectively, using Radio Telescope Effelsberg (MPIfR). The most important conclusion of the analysis is, that the strongest single pulse emission at 4.85 GHz and 8.35 GHz contributes almost exclusively to the trailing part of the leading component of the pulsar mean profile, whereas studies at lower frequencies report that the contribution is spread almost uniformly covering all phases of the pulsar mean profile. We also estimate the radio emission heights to be around 1%--2% of the light cylinder radius which is in agreement with previous studies. Additionally these observations allowed us to add two more measurements of the flux density to the PSR B1133+16 broadband radio spectrum covering frequencies from 16.7 MHz up to 32 GHz. We fit two different models to the spectrum: the broken power law and...

  4. 35 GHz gyroklystron amplifier development at NRL

    Choi, J.J. [Science Applications International Corp., McLean, VA (United States); Ganguly, A.K. [Omega-P, Inc., New Haven, CT (United States); Blank, M. [Naval Research Lab., Washington, DC (United States). Vacuum Electronics Branch] [and others

    1996-12-31

    Experiments on a two-cavity gyroklystron are underway to demonstrate a 140 kW, 35 GHz gyroklystron amplifier, operating at a fundamental beam cyclotron mode and a TE{sub 011} cylindrical cavity mode. A high power electron beam of 70 kV, 6.6A is produced from a magnetron-injection-gun which is optimally designed for the TE{sub 01} mode at 35 GHz. Drift tubes consisting of lossy ceramic rings (80% BeO, 20% SiC) are designed to suppress undesired oscillations. A drive power is injected into the first cavity through a multi-hole coaxial coupler. A capacitive probe is placed directly before the input cavity to measure the beam velocity ratio. Large signal nonlinear calculations predict a peak efficiency of 30% (extracted power = 140 kW) and a saturated gain of 20dB over a 0.3% bandwidth at {alpha} = 1.5, {Delta}v{sub z}/v{sub z} = 20% at 13.3 kG and Q{sub 1} = Q{sub 2} = 200. Design parameters and initial hot-test results of the amplifier will be presented.

  5. High Power 35GHz Gyroklystron Amplifiers

    Choi, Jin; McCurdy, A.; Wood, F.; Kyser, R.; Danly, B.; Levush, B.; Parker, R.

    1997-05-01

    High power coherent radiation sources at 35GHz are attractive for next generation high gradient particle accelerators. A multi-cavity gyroklystron amplifier is considered a promising candidate for high power millimeter wave generation. Experiments on two-cavity and three cavity gyroklystron amplifiers are underway to demonstrate a 140kW, 35GHz coherent radiation amplification. Though this power is low compared with that needed for colliders, many of the issues associated with the bandwidth of such devices can be addressed in the present experiments. High bandwidth is important to permit the rapid phase shifts required for RF pulse compression schemes presently under investigation. Large signal calculations (P.E. Latham, W. Lawson, V. Irwin, IEEE Trans. Plasma Sci., Vol. 22, No. 5, pp. 804-817, 1994.) predict that the two-cavity gyroklystron produces a peak power of 140kW, corresponding to 33% efficiency. Calculations also show that a stagger tuned three cavity circuit increases a bandwidth to more than 0.7%. Experimental results of the amplifier will be presented and compared with the theory.

  6. GHZ extraction yield for multipartite stabilizer states

    Let vertical bar Ψ> be an arbitrary stabilizer state distributed between three remote parties, such that each party holds several qubits. Let S be a stabilizer group of vertical bar Ψ>. We show that vertical bar Ψ> can be converted by local unitaries into a collection of singlets, GHZ states, and local one-qubit states. The numbers of singlets and GHZs are determined by dimensions of certain subgroups of S. For an arbitrary number of parties m we find a formula for the maximal number of m-partite GHZ states that can be extracted from vertical bar Ψ> by local unitaries. A connection with earlier introduced measures of multipartite correlations is made. An example of an undecomposable four-party stabilizer state with more than one qubit per party is given. These results are derived from a general theoretical framework that allows one to study interconversion of multipartite stabilizer states by local Clifford group operators. As a simple application, we study three-party entanglement in two-dimensional lattice models that can be exactly solved by the stabilizer formalism

  7. 28 GHz Gyrotron ECRH on LDX

    Woskov, P. P.; Kesner, J.; Michael, P. C.; Garnier, D. T.; Mauel, M. E.

    2010-12-01

    A 10 kW, CW, 28 GHz gyrotron has been implemented on LDX to increase the plasma density and to more fully explore the potential of high beta plasma stability in a dipole magnetic configuration. This added power represents about a 60% increase in ECRH to a new total of 26.9 kW with sources at 2.45, 6.4, and 10.5 GHz. The 1 Tesla resonances in LDX form small rings encompassing the entire plasma cross-section above and below the floating coil (F-coil) near the dipole axial region. A 32.5 mm diameter TE01 waveguide with a partial Vlasov step cut launches a diverging beam from above the F-coil that depends on internal wall reflections for plasma coupling. Initial gyrotron only plasmas exhibit steep natural profiles with fewer hot electrons than with the other sources. The background scattered radiation suggests that only about half the power is being absorbed with the present launcher.

  8. Gigahertz frequency flexible carbon nanotube transistors

    Chimot, N.; Derycke, V.; Goffman, M. F.; Bourgoin, J. P.; Happy, H.; Dambrine, G.

    2007-10-01

    We investigate the high frequency performances of flexible field-effect transistors based on carbon nanotubes. A large density of mostly aligned carbon nanotubes deposited on a flexible substrate by dielectrophoresis serves as the channel. The transistors display a constant transconductance up to at least 6GHz and a current gain cutoff frequency (fT) as high as 1GHz at VDS=-700mV. Bending tests show that the devices can withstand a high degree of flexion characterized by a constant transconductance for radius of curvature as small as 3.3mm.

  9. Making Maps from Planck LFI 30GHz Data with Asymmetric Beams and Cooler Noise

    The Planck CTP Working Group; Ashdown, M.A.J.; Baccigalupi, C.; Bartlett, J.G.; Borrill, J.; Cantalupo, C.; de Gasperis, G.; Gorski, K.M.; Hivon, E.; Huffenberger, K.; Keihanen, E.; Keskitalo, R.; Kisner, T.; Hurki-Suonio, H.; Lawrence, C.R.; Natoli, P.; Poutanen, T.; Prezeau, G.; Reinecke, M.; Rocha, G.; Sandri, M.; Stompor, R..; Villa, F.; Wandelt, B.; de Troia, G.

    2008-06-19

    The Planck satellite will observe the full sky at nine frequencies from 30 to 857 GHz. Temperature and polarization frequency maps made from these observations are prime deliverables of the Planck mission. The goal of this paper is to examine the effects of four realistic instrument systematics in the 30 GHz frequency maps: non-axially-symmetric beams, sample integration, sorption cooler noise, and pointing errors. They simulated one year long observations of four 30 GHz detectors. The simulated timestreams contained CMB, foreground component (both galactic and extra-galactic), instrument nolise (correlated and white), and the four instrument systematic effects. They made maps from the timelines and examined the magnitudes of the systematics effects in the maps and their angular power spectra. They also compared the maps of different mapmaking codes to see how they performed. They used five mapmaking codes (two destripers and three optimal codes). None of their mapmaking codes makes an attempt to deconvolve the beam from its output map. Therefore all our maps had similar smoothing due to beams and sample integration. This is a complicated smoothing, because every map pixel has its own effective beam. Temperature to polarization cross-coupling due to beam mismatch causes a detectable bias in the TE spectrum of the CMB map. The effects of cooler noise and pointing errors did not appear to be major concerns for the 30 GHz channel. The only essential difference found so far between mapmaking codes that affects accuracy (in terms of residual RMS) is baseline length. All optimal codes give essentially indistiguishable results. A destriper gives the same result as the optimal codes when the baseline is set short enough (Madam). For longer baselines destripers (Springtide and Madam) require less computing resources but deliver a noisier map.

  10. Coherence bandwidth characterization in an urban microcell at 62.4 GHz

    Sánchez, M. G.; Hammoudeh, A. M.; Grindrod, E.;

    2000-01-01

    Results of experiments made at 62.4 GHz in an urban mobile radio environment to characterize the coherence bandwidth are presented. The correlation coefficients between signal envelopes separated in frequency are measured and expressed as functions of distance from the base station. Due to the hi...... this parameter from the frequency correlation function obtained at each position may yield incorrect results. The coherence bandwidths for correlation levels of 0.5, 0.7, and 0.9 are given. A ray-tracing tool has been used to assist in interpreting experimental results....

  11. A broadband ferromagnetic resonance spectrometer to measure thin films up to 70 GHz.

    Harward, I; O'Keevan, T; Hutchison, A; Zagorodnii, V; Celinski, Z

    2011-09-01

    We report the development of a broadband ferromagnetic resonance (FMR) system operating in the frequency range from 10 MHz to 70 GHz using a closed-cycle He refrigeration system for measurements of thin films and micron/nano structures. The system is capable of carrying out measurements in frequency and field domain. Using two coplanar waveguides, it is capable of simultaneously measuring two samples in the out of plane and in plane FMR geometries. The system operates in the temperature range of 27-350 K and is sensitive to less than one atomic monolayer of a single crystal Fe film. PMID:21974627

  12. A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

    Islam, M M; Faruque, M R I; Islam, M T

    2014-01-01

    A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm(2), and VSWR WLAN band. PMID:24971379

  13. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    Dewani, Aliya A., E-mail: a.ashraf@griffith.edu.au; O’Keefe, Steven G.; Thiel, David V.; Galehdar, Amir [School Of Electrical Engineering, Griffith University, Brisbane, 4111 (Australia)

    2015-02-15

    A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

  14. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers

  15. Optically transparent frequency selective surfaces on flexible thin plastic substrates

    Dewani, Aliya A.; O'Keefe, Steven G.; Thiel, David V.; Galehdar, Amir

    2015-02-01

    A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

  16. GHz-rate optical parametric amplifier in hydrogenated amorphous silicon

    We demonstrate optical parametric amplification operating at GHz-rates at telecommunications wavelengths using a hydrogenated amorphous silicon waveguide through the nonlinear optical process of four-wave mixing. We investigate how the parametric amplification scales with repetition rate. The ability to achieve amplification at GHz-repetition rates shows hydrogenated amorphous silicon’s potential for telecommunication applications and a GHz-rate optical parametric oscillator. (paper)

  17. Modelling of Multilayered Wideband LTCC Filter 10 GHz

    Osypchuk, S. O.; Isniuk, T. V.; Shelkovnikov, B. N.

    2010-01-01

    This paper presents multilayered wideband filter (WBF) 10 GHz based on technology Low Temperature Co-Fired Ceramic (LTCC). WBF uses threedimensionally (3D) coupled helical inductors. WBF exhibits 3-dB bandwidth 9,3?10,6 GHz (1,3 GHz). The size of WBF is 2,3?1,6?0,8 mm. The results of modelling were got in electrodynamics package CST MicroWave Studio 2009.

  18. 20/30 GHz dual-band circularly polarized reflectarray antenna based on the concentric dual split-loop element

    Smith, Thomas Gunst; Vesterdal Larsen, Niels; Vesterager Gothelf, Ulrich;

    2012-01-01

    separate frequency bands, by rotation of the individual split-loops. Cross-polar reflection is simultaneously minimized by optimizing the gaps in the split-loops. Based on the element characteristics, an iterative design procedure is proposed and used to design a front-fed reflectarray antenna. The......A concentric dual split-loop element is designed and investigated for reflectarray antenna design in the emerging 20 GHz and 30 GHz Ka-band satellite communication spectrum. The element is capable of providing adjustment of the phase of reflection coefficients for circular plane waves in two...

  19. Development and characterization of nickel–zinc spinel ferrite for microwave absorption at 2.4 GHz

    A Kakirde; B Sinha; S N Sinha

    2008-10-01

    This paper deals with the development and characterization of nickel–zinc spinel ferrite (Ni(1–) ZnFe2O4) for microwave absorption at 2.4 GHz (ISM band). The ferrite powder was prepared by dry attrition and sintering process. Complex permittivity and permeability of the prepared sample have been determined by measuring its scattering parameters with the help of a vector network analyser. The measured parameters have been used to determine its wave absorption properties over a frequency range 2.1–2.6 GHz.

  20. Class I Methanol Maser Observations at 44 GHz in the Direction of some SNRs and SFRs.

    Larionov, G. M.; Litovchenko, I. D.; Val'tts, I. E., Alakoz, A. V.

    2011-05-01

    The results of searching for class I methanol maser emission in the interstellar medium are presented. Observations at Onsala 20-m radio telescope at 44 GHz in methanol transition 7_0-6_1A has been conducted in the direction of different types of objects of the northern hemisphere: in a little-studied region of maser emission G27.4-0.2, in some supernova remnants, in high mass protostars regions, in the dust rings around HII regions and in protostellar candidates associated with powerful bipolar outflows. In the source G27.4-0.2, which is identified with two SNR well known G27.4 +0.0 (Kes73) and possible G27.3-0.2 - class I methanol maser emission was detected at the frequency of 44 GHz. In the vicinity of the maser a map of size (27 'x 27') has been obtained. It was shown that emission at 44 GHz is formed only within the previously known maser region at 95 GHz. In four supernova remnants class I methanol maser emission was not detected at the coordinates of satellite OH (1720) maser emission. In the direction of high mass star-forming regions 9 new class I methanol masers were detected at 44 GHz. These 9 new masers are from areas characterized by high density and lack of continuum radio emission. This fact indicates the absence of ultra-compact HII regions, hence the young age of star forming regions, which have not yet formed protostar to ensure the ionization of the environment. This conclusion confirms the hypothesis of a purely collisional pumping of class I methanol masers.

  1. A New E-Band (60 - 90 GHz) Fourier Transform Millimeter-Wave Spectrometer

    Halfen, D. T.; Ziurys, L. M.

    2013-06-01

    An E-band (60 - 90 GHz) cavity Fourier transform millimeter-wave (FTmmW) spectrometer system has been built and used for molecular measurements for the first time. These frequencies are the highest acheived using cavity FTM/mmW techniques. This new system, implemented as a millimeter frequency band on the current FTMW spectrometer of the Ziurys group, utilizes waveguide for radiation propagation and commercial E-band doublers and quadruplers to achieve continuous operation from 60 to 90 GHz. This system also employs an ALMA Band 2 low-noise amplifier (LNA), designed by NRAO. The Fabry-Perot cavity consists of two 170 mm diameter mirrors with a radius of curvature of 840 mm and a separation of 700 mm. The Q factor of the system is around 100,000. Using this system, the N_{Ka,Kc} = 4_{04} → 3_{03} transition of ScC_2 near 62 GHz has been recorded for the first time. These data, as well as other molecular lines, will be presented.

  2. Jupiter's Radio Spectrum from 0.074 up to 15 GHz

    de Pater, I.; Butler, B.

    2001-12-01

    We have conducted a brief campaign in September 1998 to determine Jupiter's radio spectrum from 74 MHz up to 15 GHz. Jupiter was clearly detected at 74 MHz, the lowest frequency at which this planet's synchrotron radiation has been observed without contamination by the intense decametric emissions (there is no decametric emission at frequencies over 40 MHz). Simultaneously with the 74/330 MHz observations at the VLA, the planet was observed with the following telescopes: CLFST (151 MHz), WSRT (350, 610, 840, and 1380 MHz), MOST (843 MHz), Parkes (1350 MHz), 140-foot Green Bank (1370, 1470 MHz), DSN-Goldstone (2295 MHz, 8480 MHz), Effelsberg (2695, 4850 MHz), and HartRAO (8580, 5000 MHz). In Jan. 1996 we observed Jupiter with the VLA at 2 and 20 cm; these data will be combined with the Sep. 1998 data to extend the spectrum up to 15 GHz. The Goldstone data were obtained by the NASA/JPL Jupiter Patrol, and the Goldstone-Apple Valley Radio Telescope project. Jupiter's spectrum appears to be quite flat from 74 MHz up to 1.4 GHz, beyond which the flux density drops markedly. Model calculations as published by de Pater and co-authors match the spectral shape quite well. At the meeting we will show Jupiuter's spectrum and the spectra of several calibrators used to finetune the final spectral calibration.

  3. Making Maps from Planck LFI 30GHz Data with Asymmetric Beams and Cooler Noise

    Ashdown, M A J; Bartlett, J G; Borrill, J; Cantalupo, C; De Gasperis, G; de Troia, G; Górski, K M; Hivon, E; Huffenberger, Kevin M; Keihanen, E; Keskitalo, R; Kisner, T; Kurki-Suonio, H; Lawrence, C R; Natoli, P; Poutanen, T; Prezeau, G; Reinecke, M; Rocha, G; Sandri, M; Stompor, R; Villa, F; Wandelt, B

    2008-01-01

    The Planck satellite will observe the full sky at nine frequencies from 30 to 857 GHz. The goal of this paper is to examine the effects of four realistic instrument systematics in the 30 GHz frequency maps: non-axially-symmetric beams, sample integration, sorption cooler noise, and pointing errors. We simulated one year long observations of four 30 GHz detectors. The simulated timestreams contained CMB, foreground components (both galactic and extra-galactic), instrument noise (correlated and white), and the four instrument systematic effects. We made maps from the timelines and examined the magnitudes of the systematics effects in the maps and their angular power spectra. We also compared the maps of different mapmaking codes to see how they performed. We used five mapmaking codes (two destripers and three optimal codes). None of our mapmaking codes makes an attempt to deconvolve the beam from its output map. Therefore all our maps had similar smoothing due to beams and sample integration. Temperature to pol...

  4. Propagation Channel Comparison between 23.5 and 45 GHz in Conference Scenario

    Jianwu Dou

    2016-01-01

    Full Text Available The characteristics of propagation channel at 23.5 and 45 GHz in an indoor conference room are studied based on hybrid approach. A ray-based simulator which includes the reflection, penetration, diffraction, and diffuse scattering is adopted to generate the massive channel realizations. This platform is well calibrated in path and power delay profile (PDP levels according to some specified measurements at different frequencies. Subsequently, according to the simulated channel samples, the statistical channel model for both the large and small scale characteristics is established based on the alpha-beta approach and extended Saleh-Valenzuela (S-V structure, respectively. Results show that the slope of fitted path loss (PL is less than free space due to the waveguide effect for both 23.5 and 45 GHz in indoor scenario and larger PL is experienced at higher frequency. Additionally, the cluster is more centralized with less spreads and decaying faster in delay domain at 45 GHz.

  5. Space VLBI Observations of 3C 279 at 1.6 and 5 GHz

    Piner, B G; Wehrle, A E; Hirabayashi, H; Lovell, J E J; Unwin, S C

    2000-01-01

    We present the first VLBI Space Observatory Programme (VSOP) observations ofthe gamma-ray blazar 3C 279 at 1.6 and 5 GHz. The combination of the VSOP andVLBA-only images at these two frequencies maps the jet structure on scales from1 to 100 mas. On small angular scales the structure is dominated by the quasarcore and the bright secondary component `C4' located 3 milliarcseconds from thecore (at this epoch). On larger angular scales the structure is dominated by ajet extending to the southwest, which at the largest scale seen in these imagesconnects with the smallest scale structure seen in VLA images. We haveexploited two of the main strengths of VSOP: the ability to obtainmatched-resolution images to ground-based images at higher frequencies and theability to measure high brightness temperatures. A spectral index map was madeby combining the VSOP 1.6 GHz image with a matched-resolution VLBA-only imageat 5 GHz from our VSOP observation on the following day. The spectral index mapshows the core to have a highl...

  6. A 33 GHz VSA survey of the Galactic plane from 27 to 46 degrees

    Todorović, M; Dickinson, C; Davis, R J; Cleary, K A; Genova-Santos, R; Grainge, K J B; Hafez, Y A; Hobson, M P; Jones, M E; Lancaster, K; Rebolo, R; Reich, W; Rubiño-Martin, J A; Saunders, R D E; Savage, R S; Scott, P F; Slosar, A; Taylor, A C; Watson, R A

    2010-01-01

    The Very Small Array (VSA) has been used to survey the l = 27 to 46 deg, |b|<4 deg region of the Galactic plane at a resolution of 13 arcmin. The survey consists of 44 pointings of the VSA, each with a r.m.s. sensitivity of ~90 mJy/beam. These data are combined in a mosaic to produce a map of the area. The majority of the sources within the map are HII regions. We investigated anomalous radio emission from the warm dust in 9 HII regions of the survey by making spectra extending from GHz frequencies to the FIR IRAS frequencies. Acillary radio data at 1.4, 2.7, 4.85, 8.35, 10.55, 14.35 and 94 GHz in addition to the 100, 60, 25 and 12 micron IRAS bands were used to construct the spectra. From each spectrum the free-free, thermal dust and anomalous dust emission were determined for each HII region. The mean ratio of 33 GHz anomalous flux density to FIR 100 micron flux density for the 9 selected HII regions was 1.10 +/-0.21x10^(-4). When combined with 6 HII regions previously observed with the VSA and the CBI, ...

  7. Observation of clouds with the newly developed cloud profiling FM-CW radar at 95 GHz

    Takano, Toshiaki; Akita, Ken-ichi; Kubo, Hiroshi; Kawamura, Youhei; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2005-10-01

    We developed a low-power and high-sensitivity cloud profiling radar transmitting frequency modulated continuous wave (FM-CW) at 95 GHz for ground-based observations. Millimeter wave at 95 GHz is used to realize much higher sensitivity than lower frequencies to small cloud particles. An FM-CW type radar realizes similar sensitivity with much smaller output power to a pulse type radar. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 20 km in height with a resolution of 15 m. Using the developed millimeter-wave FM-CW radar at 95 GHz, we observed clouds in a campaign observation in Amami Island in March 2003, and on a sail on Mirai, a Japanese scientific research vessel, in September 2004 to January 2005 in the Arctic Ocean and the southwest of the Pacific Ocean. The radar provided good and sensitive data in these long-term observations.

  8. Customer premise service study for 30/20 GHz satellite system

    Milton, R. T.; Ross, D. P.; Harcar, A. R.; Freedenberg, P.; Schoen, D.

    1983-01-01

    Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band.

  9. Comparison of OQPSK and CPM for Communications at 60 GHz with a Nonideal Front End

    Jimmy Nsenga

    2007-03-01

    Full Text Available Short-range digital communications at 60 GHz have recently received a lot of interest because of the huge bandwidth available at those frequencies. The capacity offered to the users could finally reach 2 Gbps, enabling the deployment of new multimedia applications. However, the design of analog components is critical, leading to a possible high nonideality of the front end (FE. The goal of this paper is to compare the suitability of two different air interfaces characterized by a low peak-to-average power ratio (PAPR to support communications at 60 GHz. On one hand, we study the offset-QPSK (OQPSK modulation combined with a channel frequency-domain equalization (FDE. On the other hand, we study the class of continuous phase modulations (CPM combined with a channel time-domain equalizer (TDE. We evaluate their performance in terms of bit error rate (BER considering a typical indoor propagation environment at 60 GHz. For both air interfaces, we analyze the degradation caused by the phase noise (PN coming from the local oscillators; and by the clipping and quantization errors caused by the analog-to-digital converter (ADC; and finally by the nonlinearity in the PA.

  10. Comparison of OQPSK and CPM for Communications at 60 GHz with a Nonideal Front End

    Nsenga Jimmy

    2007-01-01

    Full Text Available Short-range digital communications at 60 GHz have recently received a lot of interest because of the huge bandwidth available at those frequencies. The capacity offered to the users could finally reach 2 Gbps, enabling the deployment of new multimedia applications. However, the design of analog components is critical, leading to a possible high nonideality of the front end (FE. The goal of this paper is to compare the suitability of two different air interfaces characterized by a low peak-to-average power ratio (PAPR to support communications at 60 GHz. On one hand, we study the offset-QPSK (OQPSK modulation combined with a channel frequency-domain equalization (FDE. On the other hand, we study the class of continuous phase modulations (CPM combined with a channel time-domain equalizer (TDE. We evaluate their performance in terms of bit error rate (BER considering a typical indoor propagation environment at 60 GHz. For both air interfaces, we analyze the degradation caused by the phase noise (PN coming from the local oscillators; and by the clipping and quantization errors caused by the analog-to-digital converter (ADC; and finally by the nonlinearity in the PA.

  11. The 94 GHz MMW imaging radar system

    Alon, Yair; Ulmer, Lon

    1993-01-01

    The 94 GHz MMW airborne radar system that provides a runway image in adverse weather conditions is now undergoing tests at Wright-Patterson Air Force Base (WPAFB). This system, which consists of a solid state FMCW transceiver, antenna, and digital signal processor, has an update rate of 10 times per second, 0.35x azimuth resolution and up to 3.5 meter range resolution. The radar B scope (range versus azimuth) image, once converted to C scope (elevation versus azimuth), is compatible with the standard TV presentation and can be displayed on the Head Up Display (HUD) or Head Down Display (HDD) to aid the pilot during landing and takeoff in limited visibility conditions.

  12. Deposited low temperature silicon GHz modulator

    Lee, Yoon Ho Daniel; Lipson, Michal

    2013-01-01

    The majority of silicon photonics is built on silicon-on-insulator (SOI) wafers while the majority of electronics, including CPUs and memory, are built on bulk silicon wafers, limiting broader acceptance of silicon photonics. This discrepancy is a result of silicon photonics's requirement for a single-crystalline silicon (c-Si) layer and a thick undercladding for optical guiding that bulk silicon wafers to not provide. While the undercladding problem can be partially addressed by substrate removal techniques, the complexity of co-integrating photonics with state-of-the-art transistors and real estate competition between electronics and photonics remain problematic. We show here a platform for deposited GHz silicon photonics based on polycrystalline silicon with high optical quality suitable for high performance electro-optic devices. We demonstrate 3 Gbps polysilicon electro-optic modulator fabricated on a deposited polysilicon layer fully compatible with CMOS backend integration. These results open up an arr...

  13. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-03-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  14. Icecube: Spaceflight Validation of an 874-GHz Submillimeter Wave Radiometer for Ice Cloud Remote Sensing

    Wu, D. L.; Esper, J.; Ehsan, N.; Piepmeier, J. R.; Racette, P.

    2014-12-01

    Ice clouds play a key role in the Earth's radiation budget, mostly through their strong regulation of infrared radiation exchange. Submillimeter wave remote sensing offers a unique capability to improve cloud ice measurements from space. At 874 GHz cloud scattering produces a larger brightness temperature depression from cirrus than lower frequencies, which can be used to retrieve vertically-integrated cloud ice water path (IWP) and ice particle size. The objective of the IceCube project is to retire risks of 874-GHz receiver technology by raising its TRL from 5 to 7. The project will demonstrate, on a 3-U CubeSat in a low Earth orbit (LEO) environment, the 874-GHz receiver system with noise equivalent differential temperature (NEDT) of ~0.2 K for 1-second integration and calibration error of 2.0 K or less as measured from deep-space observations. The Goddard Space Flight Center (GSFC) is partnering with Virginia Diodes, Inc (VDI) to qualify commercially available 874-GHz receiver technology for spaceflight, and demonstrate the radiometer performance. The instrument (submm-wave cloud radiometer, or SCR), along with the CubeSat system developed and integrated by GSFC, will be ready for launch in two years. The instrument subsystem includes a reflector antenna, sub-millimeter wave mixer, frequency multipliers and stable local oscillator, an intermediate frequency (IF) circuit with noise injection, and data-power boards. The mixer and frequency multipliers are procured from VDI with GSFC insight into fabrication and testing processes to ensure scalability to spaceflight beyond TRL 7. The remaining components are a combination of GSFC-designed and commercial off-the-shelf (COTS) at TRLs of 5 or higher. The spacecraft system is specified by GSFC and comprises COTS components including three-axis stabilizer and sun sensor, GPS receiver, deployable solar arrays, UHF radio, and 2 GB of on-board storage. The spacecraft and instrument are integrated and flight qualified

  15. Bit error rate analysis of Wi-Fi and bluetooth under the interference of 2.45 GHz RFID

    2007-01-01

    IEEE 802.11b WLAN (Wi-Fi) and IEEE 802.15.1 WPAN (bluetooth) are prevalent nowadays, and radio frequency identification (RFID) is an emerging technology which has wider applications. 802.11b occupies unlicensed industrial, scientific and medical (ISM) band (2.4-2.483 5 GHz) and uses direct sequence spread spectrum (DSSS) to alleviate the narrow band interference and fading. Bluetooth is also one user of ISM band and adopts frequency hopping spread spectrum (FHSS) to avoid the mutual interference. RFID can operate on multiple frequency bands, such as 135 KHz, 13.56 MHz and 2.45 GHz. When 2.45 GHz RFID device, which uses FHSS, collocates with 802.11b or bluetooth, the mutual interference is inevitable. Although DSSS and FHSS are applied to mitigate the interference, their performance degradation may be very significant. Therefore, in this article, the impact of 2.45 GHz RFID on 802.11b and bluetooth is investigated. Bit error rate (BER) of 802.11b and bluetooth are analyzed by establishing a mathematical model, and the simula-tion results are compared with the theoretical analysis to justify this mathematical model.

  16. Z45: A New 45-GHz Band Dual-Polarization HEMT Receiver for the NRO 45-m Radio Telescope

    Nakamura, Fumitaka; Yonekura, Yoshinori; Kimura, Kimihiko; Okada, Nozomi; Kozu, Minato; Hasegawa, Yutaka; Tokuda, Kazuki; Ochiai, Tetsu; Mizuno, Izumi; Dobashi, Kazuhito; Shimoikura, Tomomi; Kameno, Seiji; Taniguchi, Kotomi; Shinnaga, Hiroko; Takano, Shuro; Kawabe, Ryohei; Nakajima, Taku; Iono, Daisuke; Kuno, Nario; Onishi, Toshikazu; Momose, Munetake; Yamamoto, Satoshi

    2015-01-01

    We developed a dual-linear-polarization HEMT (High Electron Mobility Transistor) amplifier receiver system of the 45-GHz band (hereafter Z45), and installed it in the Nobeyama 45-m radio telescope. The receiver system is designed to conduct polarization observations by taking the cross correlation of two linearly-polarized components, from which we process full-Stokes spectroscopy. We aim to measure the magnetic field strength through the Zeeman effect of the emission line of CCS ($J_N=4_3-3_2$) toward pre-protostellar cores. A linear-polarization receiver system has a smaller contribution of instrumental polarization components to the Stokes $V$ spectra than that of the circular polarization system, so that it is easier to obtain the Stokes $V$ spectra. The receiver has an RF frequency of 42 $-$ 46 GHz and an intermediate frequency (IF) band of 4$-$8 GHz. The typical noise temperature is about 50 K, and the system noise temperature ranges from 100 K to 150K over the frequency of 42 $-$ 46 GHz. The receiver s...

  17. Planck 2013 results. VI. High Frequency Instrument data processing

    Ade, P.A.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J. -P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bowyer, J.W.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J. -F.; Catalano, A.; Chamballu, A.; Chary, R. -R.; Chen, X.; Chiang, L. -Y; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J. -M.; Désert, F. -X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Enßlin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Girard, D.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Herent, O.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hou, Z.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J. -M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Jeune, M. Le; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; MacTavish, C.J.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M. -A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; North, C.; Noviello, F.; Novikov, D.; Novikov, I.; Orieux, F.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J. -L.; Rachen, J.P.; Racine, B.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sanselme, L.; Santos, D.; Sauvé, A.; Savini, G.; Shellard, E.P.S.; Spencer, L.D.; Starck, J. -L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A. -S.; Sygnet, J. -F.; Tauber, J.A.; Tavagnacco, D.; Techene, S.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; White, S.D.M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (hereafter HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857 GHz with an angular resolution ranging from 9.7 to 4.6 arcmin. The detector noise per (effective) beam solid angle is respectively, 10, 6, 12 and 39 microKelvin in HFI four lowest frequency channel (100--353 GHz) and 13 and 14 kJy/sr for the 545 and 857 GHz channels. Using the 143 GHz channel as a reference, these two high frequency channels are intercalibrated within 5% and the 353 GHz relative calibration is at the percent level. The 100 and 217 GHz channels, which together with the 143 GHz channel determine the high-multipole part of the CMB power spectrum (50 < l <2500), are intercalibrated at better than 0.2 %.

  18. Frequency Reconfigurable Hybrid Slot Antenna Using PIN Diodes

    Yang, Xiaolin; Sheng, Lili; Lin, Jiancheng; Chen, Gang

    2015-11-01

    This paper introduces a frequency reconfigurable hybrid slot antenna fed by coplanar waveguide (CPW) without complex bias network and DC blocking capacitor chips. In order to add reconfigurablility to the antenna, the PIN diodes are equipped in the slots. The antenna is capable of frequency switching at six different frequency bands between 1.7 GHz to 2.5 GHz, which can be used in multiradio wireless systems, such as DCS-1800, PCS1900, UMTS, Wibro and Bluetooth bands. The simulated and measured return loss, peak gain, together with the radiation patterns are presented and compared. Especially, the radiation patterns are stable at different frequency.

  19. Parametric Study of a Small Size 5.8 GHz Slotted Patch Antenna

    Chandra Prakash

    2014-05-01

    Full Text Available This paper presents a design of a coaxially fed microstrip patch antenna (MSPA with multiple slots for applications in BAN (Body Area Networks, PAN (personal area network and WLAN (Wireless Local Area Network at 5.8 GHz. The radiation characteristics and the impedance matching of the proposed antenna are evaluated. The parametric study of slot dimensions and position has been performed to optimize the design for high return loss and increased bandwidth. The maximum achievable bandwidth below -10dB is about 590 MHz with peak gain of 5.47dB. The reflection coefficient S11 of -42dB is obtained at resonating frequency of 5.8 GHz in the Industrial Scientific and Medical band (ISM

  20. A 23 GHz high-temperature superconducting microstrip filter for radio astronomy

    GAO Lu; GUO Jin; WANG YueHui; YU Tao; ZHANG Qiang; LI ChunGuang; ZHANG XueQiang; LI Hong; LI JunJie; LI WuXia; GU ChangZhi; MENG JiBao; FENG Ji; HE YuSheng

    2009-01-01

    This paper reports a 6-pole high-temperature superconducting (HTS) microstrip bandpass filter for radio astronomy applications. The filter has a center frequency of 23 GHz and a bandwidth the 2 GHz. We have made many efforts, such as adopting 0.25-mm-thick substrate, carefully designing the housing box and filter layout, to solve the problems in realizing a K-band planar filter. A special straight-line half-wavelength resonator (center-widen resonator) was also designed to reduce the insertion loss of the filter. The measured results showed a midband insertion loss of 0.11 dB with a ripple of 0.4 dB, and a return loss better than 11.5 dB. Good agreement was obtained between simulated and measured re-suits.

  1. Design and Fabrication of 35 GHz GaAs Gunn Diodes .

    Ishwar Chandra

    1995-01-01

    Full Text Available The paper describes design and fabrication of GaAs 100 mW Gunn diodes for operation at ~35 GHz. As the devices have low efficiency, a large ammount of input power is dessipated as heat, resulting in temperature rise in the device during operation beyond tolerable limits. Heat from these devices can be removed quickly and efficiently by using gold as integral heat sink (IHS. Further, the temperature of the device can be controlled by monitoring device area. Calculations for heat flow and expected efficiency have been done. Required Gunn structure has been grown by molecular beam epitaxy technique. The devices have been fabricated by IHS-IBR integral bonding ribbon technique. From the devices developed, 100 mW of output has been achieved in the frequency range 33-38 GHz with an efficiency of 3-4 percent.

  2. Novel Planar Horn Antenna for 75/85 GHz Experimental Wireless Link

    J. Puskely

    2015-09-01

    Full Text Available In the paper, we describe a novel H-plane horn antenna for an experi¬mental wireless link operating in frequency bands 71 to 76 GHz and 81 to 86 GHz. The horn antenna was designed considering a substrate integrated waveguide (SIW technology, The waveguide WR12 was used as a feeder. In order to improve transition between a thin-substrate SIW horn antenna and the air, we combined two approaches; a printed transition and a dielectric load. That way, a better impedance matching and better radiation properties were reached. In comparison with other planar horn antennas, we obtained a more directional radiation pattern with more than 5 dB higher gain and sufficient side lobe suppression in the E-plane. The novel planar H-plane horn antenna was compared with a designed conventional metallic horn antenna.

  3. DESIGN OF 2.4 GHz CMOS POWER AMPLIFIER FOR WIRELESS COMMUNICATION

    Atul V. Jiwtode,

    2014-04-01

    Full Text Available This paper gives the information about designing the 2.4GHz CMOS power amplifier for wireless communication using 130nm technology. Previously work present different approaches for designing the CMOS power amplifier for different class with different technology. This paper proposed class-B power amplifier using 130 nm technology for gain more than 15dB.The class-B power amplifier is design and to meet the frequency response for 2.4 GHz with gain of 67.321dB, the proposed power supply work with the voltage from 1.3 to 3V, which means that we can used these design for battery aided hand held electronic moving or electronic mobile communication equipment .The proposed power amplifier is designed using ADS tool.

  4. A 12–16 GHz microelectromechanical system-switchable bandpass filter

    This paper describes a novel monolithic switchable filter covering a bandpass frequency of 12–16 GHz at the Ku-band on a silicon substrate. The filter structure is based on parallel-coupled half-wavelength resonator topologies and microelectromechanical system-tunable resonators designed by placing ohmic switches at the open ends of the microstrip resonators. A wideband coplanar waveguide is designed for microstrip transition without via holes during wafer testing. The measured results show a minimum insertion loss of 3.6 dB, a return loss better than 15 dB, a 10.2% fractional bandwidth and a 14.2% tuning range from 13 to 15 GHz. The fabricated filter has a chip area of 15.1 mm × 3 mm and has achieved skirt slopes of over 30 dB GHz−1. (paper)

  5. Performance Analysis of a 60 GHz Near Gigabit System for WPAN Applications

    Rakotondrainibe, Lahatra; Zaharia, Gheorghe; Grunfelder, Guy; Zein, Ghaïs El

    2010-01-01

    A 60 GHz wireless Gigabit Ethernet (G.E.) communication system capable of near gigabit data rate has been developed at IETR. The realized system covers 2 GHz available bandwidth. This paper describes the design and realization of the overall system including the baseband (BB), intermediate frequency (IF) and radiofrequency (RF) blocks. A differential binary shift keying (DBPSK) modulation and a differential demodulation are adopted at IF. In the BB processing block, an original byte/frame synchronization technique is designed to provide a small value of the preamble false alarm and missing probabilities. For the system performances, two different real scenarios are investigated: measurements carried out in a large gym and in hallways. Bit error rate (BER) measurements have been performed in different configurations: with/without RS (255, 239) coding, with frame synchronization using 32/64 bits preambles. As shown by simulation, the 64 bits preamble provides sufficient robustness and improves the system perfor...

  6. 79 GHz UWB automotive short range radar – Spectrum allocation and technology trends

    H.-L. Bloecher

    2009-05-01

    Full Text Available Automotive UWB (Ultra-Wideband short range radar (SSR is on the market as a key technology for novel comfort and safety systems. SiGe based 79 GHz UWB SRR will be a definite candidate for the long term substitution of the 24 GHz UWB SRR. This paper will give an overview of the finished BMBF joint project KOKON and the recently started successing project RoCC, which concentrate on the development of this technology and sensor demonstrators. In both projects, the responsibilities of Daimler AG deal with application based sensor specification, test and evaluation of realized sensor demonstrators. Recent UWB SRR frequency regulation approaches and activitites will be introduced. Furthermore, some first results of Daimler activities within RoCC will be presented, dealing with the packaging and operation of these sensors within the complex car environment.

  7. A 94 GHz RF Electronics Subsystem for the CloudSat Cloud Profiling Radar

    LaBelle, Remi C.; Girard, Ralph; Arbery, Graham

    2003-01-01

    The CloudSat spacecraft, scheduled for launch in 2004, will carry the 94 GHz Cloud Profiling Radar (CPR) instrument. The design, assembly and test of the flight Radio Frequency Electronics Subsystem (RFES) for this instrument has been completed and is presented here. The RFES consists of an Upconverter (which includes an Exciter and two Drive Amplifiers (DA's)), a Receiver, and a Transmitter Calibrator assembly. Some key performance parameters of the RFES are as follows: dual 100 mW pulse-modulated drive outputs at 94 GHz, overall Receiver noise figure electron-mobility transistor (HEMT) technology and the Receiver low-noise amplifier (LNA) in 0.1 micron InP HEMT technology.

  8. A 2-20 GHz Analog Lag-Correlator for Radio Interferometry

    Holler, C M; Taylor, A C; Harris, A I; Maas, S A

    2011-01-01

    We present the design and testing of a 2-20 GHz continuum band analog lag correlator with 16 frequency channels for astronomical interferometry. The correlator has been designed for future use with a prototype single-baseline interferometer operating at 185-275 GHz. The design uses a broadband Wilkinson divider tree with integral thin-film resistors implemented on an alumina substrate, and custom-made broadband InGaP/GaAs Gilbert Cell multipliers. The prototype correlator has been fully bench-tested, together with the necessary readout electronics for acquisition of the output signals. The results of these measurements show that the response of the correlator is well behaved over the band. An investigation of the noise behaviour also shows that the signal-to-noise of the system is not limited by the correlator performance.

  9. Development of a cloud profiling FM-CW radar at 95 GHz and its preliminary results

    Takano, Toshiaki; Suga, Yumiro; Takei, Kentaro; Kawamura, Youhei; Sakai, Kurt; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2003-04-01

    A cloud profiling radar transmitting frequency-modulated continuous wave (FM-CW) at 95 GHz is developed for ground-based observations. Millimeter wave at 95 GHz is used to realize high sensitivity to small cloud particles. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 15 km in height with a resolution of 15 m. The system was integrated and sensitivities and stabilities have been measured. Results of test measurements of clouds show that the system is sensitive and stable enough to observe various clouds.

  10. First observational results with the newly developed cloud profiling FM-CW radar at 95 GHz

    Takano, Toshiaki; Suga, Yumiro; Akita, Kenichi; Kawamura, Youhei; Kumagai, Hiroshi; Takamura, Tamio; Nakanishi, Yuji; Nakajima, Teruyuki

    2004-02-01

    We developed a cloud profiling radar transmitting frequency-modulated continuous wave (FM-CW) at 95 GHz for ground-based observations. Millimeter wave at 95 GHz is used to realize high sensitivity to small cloud particles. An FM-CW type radar would realize similar sensitivity with much smaller output to a pulse type radar. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 15 km in height with a resolution of 15 m. Using the facility, test observations and long term campaign observations have been done. Results of observations show that the system is sensitive and stable enough to observe various clouds.

  11. A 94 GHz RF Electronics Subsystem for the CloudSat Cloud Profiling Radar

    LaBelle, Remi C.; Girard, Ralph; Arbery, Graham

    2003-01-01

    The CloudSat spacecraft, scheduled for launch in 2004, will carry the 94 GHz Cloud Profiling Radar (CPR) instrument. The design, assembly and test of the flight Radio Frequency Electronics Subsystem (RFES) for this instrument has been completed and is presented here. The RFES consists of an Upconverter (which includes an Exciter and two Drive Amplifiers (DA's)), a Receiver, and a Transmitter Calibrator assembly. Some key performance parameters of the RFES are as follows: dual 100 mW pulse-modulated drive outputs at 94 GHz, overall Receiver noise figure knowledge accuracy of Receiver gain of monolithic microwave integrated circuit (MMIC) designs were utilized which implement the DA's in 0.1 micron GaAs high electron-mobility transistor (HEMT) technology and the Receiver low-noise amplifier (LNA) in 0.1 micron InP HEMT technology.

  12. A Method to Adjust Dielectric Property of SiC Powder in the GHz Range

    Xiaolei Su; Jie Xu; Zhimin Li; Junbo Wang; Xinhai He; Chong Fu; Wancheng Zhou

    2011-01-01

    The SiC powders by Al or N doping have been synthesized by combustion synthesis, using Al powder and NH4Cl powder as the dopants and polytetrafluoroethylene as the chemical activator. Characterization by X-ray diffraction, Raman spectrometer, scanning electron microscopy and energy dispersive spectrometer demonstrates the formation of Al doped SiC, N doped SiC and the Al and N co-doped SiC solid solution powders, respectively. The electric permittivities of prepared powders have been determined in the frequency range of 8.2-12.4 GHz. It indicates that the electric permittivities of the prepared SiC powders have been improved by the pure Al or N doping and decrease by the Al and N co-doping. The paper presents a method to adjust dielectric property of SiC powders in the GHz range.

  13. Micromachined On-Chip Dielectric Resonator Antenna Operating at 60 GHz

    Sallam, Mai

    2015-06-01

    This paper presents a novel cylindrical Dielectric Resonator Antenna (DRA) suitable for millimeter-wave on-chip systems. The antenna was fabricated from a single high resistivity silicon wafer via micromachining technology. The new antenna was characterized using HFSS and experimentally with good agreement been found between the simulations and experiment. The proposed DRA has good radiation characteristics, where its gain and radiation efficiency are 7 dBi and 79.35%, respectively. These properties are reasonably constant over the working frequency bandwidth of the antenna. The return loss bandwidth was 2.23 GHz, which corresponds to 3.78% around 60 GHz. The antenna was primarily a broadside radiator with -15 dB cross polarization level.

  14. Construction of an integrated down-converter for operation at 200 GHz

    There is currently considerable interest in the part of the electromagnetic spectrum known as the terahertz region (100 GHz to 10 THz). Traditionally, terahertz radiation was the preserve of specialist applications in astronomy, atmospheric studies and plasma diagnostics. However, potential or actual applications in such diverse fields as medicine, security, communications and military applications are now emerging. At present there are very few devices and systems that operate in this spectral region and those which exist are expensive and difficult to manufacture. For the potential of terahertz radiation to be realised by industry, a low-cost (i.e. 'manufacturable') method of constructing terahertz systems is needed; new methods of generating radiation at terahertz frequencies are also urgently required. This thesis presents the development of a novel technique for producing passive and active devices and systems for use at terahertz frequencies. This novel approach utilises standard semiconductor techniques to fabricate metal-pipe waveguides directly onto semiconductor wafers. As standard semiconductor techniques are used, it provides a possible low-cost and highly manufacturable method of producing terahertz devices and systems. The key processes that are needed to produce components and devices for terahertz systems have been developed and presented in this work. Metal-pipe rectangular waveguides for use at W-band (70 GHz - 110 GHz) and G-band (140 GHz - 220 GHz) have been fabricated and S-parameter measurements have been performed on them using a specially designed test fixture. The measured attenuation for these waveguides is approximately 0.2 dB to 5 dB per guide wavelength for W-band and 0.6 dB per guide wavelength for G-band; these results suggest that these components could be used in practical systems. A method of interfacing with terahertz systems and free-space is needed in real applications, so a horn antenna has been designed which can be

  15. Optical injection locking of monolithically integrated photonic source for generation of high purity signals above 100 GHz.

    Balakier, Katarzyna; Fice, Martyn J; van Dijk, Frederic; Kervella, Gael; Carpintero, Guillermo; Seeds, Alwyn J; Renaud, Cyril C

    2014-12-01

    A monolithically integrated photonic source for tuneable mm-wave signal generation has been fabricated. The source consists of 14 active components, i.e. semiconductor lasers, amplifiers and photodetectors, all integrated on a 3 mm(2) InP chip. Heterodyne signals in the range between 85 GHz and 120 GHz with up to -10 dBm output power have been successfully generated. By optically injection locking the integrated lasers to an external optical comb source, high-spectral-purity signals at frequencies >100 GHz have been generated, with phase noise spectral density below -90 dBc/Hz being achieved at offsets from the carrier greater than 10 kHz. PMID:25606875

  16. A broadband 47–67 GHz LNA with 17.3 dB gain in 65-nm CMOS

    A broadband 47–67 GHz low noise amplifier (LNA) with 17.3 dB gain in 65-nm CMOS technology is proposed. The features of millimeter wave circuits are illustrated first and design methodologies are discussed. The wideband input matching of the LNA was achieved by source inductive degeneration, which is narrowband in the low-GHz range but wideband at millimeter-wave frequencies due to the existence of gate–drain capacitance, Cgd. In order to minimize the noise figure (NF), the LNA used a common-source (CS) structure rather than cascode in the first stage, and the noise matching principle is explored. The last two stages of the LNA used a cascode structure to increase the power gain. Analysis of the gain boost effect of the gate inductor at the common-gate (CG) transistor is also performed. T-shape matching networks between stages are intended to enlarge the bandwidth. All on-chip inductors and transmission lines are modeled and simulated with a 3-dimensional electromagnetic (EM) simulation tool to guarantee the success of the design. Measurement results show that the LNA achieves a maximum gain of 17.3 dB at 60 GHz, while the 3-dB bandwidth is 20 GHz (47–67 GHz), including the interested band of 59–64 GHz, and the minimum noise figure is 4.9 dB at 62 GHz. The LNA absorbs a current of 19 mA from a 1.2 V supply and the chip occupies an area of 900 × 550 μm2 including pads. (paper)

  17. A broadband 47-67 GHz LNA with 17.3 dB gain in 65-nm CMOS

    Chong, Wang; Zhiqun, Li; Qin, Li; Yang, Liu; Zhigong, Wang

    2015-10-01

    A broadband 47-67 GHz low noise amplifier (LNA) with 17.3 dB gain in 65-nm CMOS technology is proposed. The features of millimeter wave circuits are illustrated first and design methodologies are discussed. The wideband input matching of the LNA was achieved by source inductive degeneration, which is narrowband in the low-GHz range but wideband at millimeter-wave frequencies due to the existence of gate-drain capacitance, Cgd. In order to minimize the noise figure (NF), the LNA used a common-source (CS) structure rather than cascode in the first stage, and the noise matching principle is explored. The last two stages of the LNA used a cascode structure to increase the power gain. Analysis of the gain boost effect of the gate inductor at the common-gate (CG) transistor is also performed. T-shape matching networks between stages are intended to enlarge the bandwidth. All on-chip inductors and transmission lines are modeled and simulated with a 3-dimensional electromagnetic (EM) simulation tool to guarantee the success of the design. Measurement results show that the LNA achieves a maximum gain of 17.3 dB at 60 GHz, while the 3-dB bandwidth is 20 GHz (47-67 GHz), including the interested band of 59-64 GHz, and the minimum noise figure is 4.9 dB at 62 GHz. The LNA absorbs a current of 19 mA from a 1.2 V supply and the chip occupies an area of 900 × 550 μm2 including pads. Project supported by the National High Technology Research and Development Program of China (No. 2011AA010202).

  18. Monitoring of Gamma-Ray Bright AGN: The Multi-Frequency Polarization of the Flaring Blazar 3C 279

    Kang, Sincheol; Lee, Sang-Sung; Byun, Do-Young

    2015-10-01

    We present results of long-term multi-wavelength polarization observations of the powerful blazar 3C 279 after its γ-ray flare on 2013 December 20. We followed up this flare with single-dish polarization observations using two 21-m telescopes of the Korean VLBI Network. Observations carried out weekly from 2013 December 25 to 2015 January 11, at 22 GHz, 43 GHz, 86 GHz simultaneously, as part of the Monitoring Of GAmma-ray Bright AGN (MOGABA) program. We measured 3C 279 total flux densities of 22-34 Jy at 22 GHz, 15-28 Jy (43 GHz), and 10-21 Jy (86 GHz), showing mild variability of ≤ 50 % over the period of our observations. The spectral index between 22 GHz and 86 GHz ranged from -0.13 to -0.36. Linear polarization angles were 27°-38°, 30°-42°, and 33°-50° at 22 GHz, 43 GHz, and 86 GHz, respectively. The degree of linear polarization was in the range of 6-12%, and slightly decreased with time at all frequencies. We investigated Faraday rotation and depolarization of the polarized emission at 22-86 GHz, and found Faraday rotation measures (RM) of -300 to -1200 rad m^{-2} between 22 GHz and 43 GHz, and -800 to -5100 rad m^{-2} between 43 GHz and 86 GHz.The RM values follow a power law with a mean power law index a of 2.2, implying that the polarized emission at these frequencies travels through a Faraday screen in or near the jet. We conclude that the regions emitting polarized radio emission may be different from the region responsible for the 2013 December γ-ray flare and are maintained by the dominant magnetic field perpendicular to the direction of the radio jet at milliarcsecond scales.

  19. Porcine skin as human body phantom at 60 GHz

    Petrillo, Luca; Mavridis, Theodoros; De Doncker, Philippe; Sarrazin, Julien; Benlarbi-Delai, Aziz

    2015-01-01

    This communication presents the results of an experimental campaign carried out at 60 GHz to demonstrate that porcine skin can be used at 60 GHz as a phantom for the human body. Norton formulations above a flat human body are verified using porcine skin.

  20. Detection of 183 GHz water megamaser emission towards NGC 4945

    Humphreys, Elizabeth; Impellizzeri, Violette; Galametz, Maud; Olberg, Michael; Conway, John; Belitsky, Victor; De Breuck, Carlos

    2016-01-01

    Aim: The aim of this work is to search Seyfert 2 galaxy NGC 4945, a well-known 22 GHz water megamaser galaxy, for water (mega)maser emission at 183 GHz. Method: We used APEX SEPIA Band 5 to perform the observations. Results: We detected 183 GHz water maser emission towards NGC 4945 with a peak flux density of ~3 Jy near the galactic systemic velocity. The emission spans a velocity range of several hundred km/s. We estimate an isotropic luminosity of > 1000 Lsun, classifying the emission as a megamaser. A comparison of the 183 GHz spectrum with that observed at 22 GHz suggests that 183 GHz emission also arises from the active galactic nucleus (AGN) central engine. If the 183 GHz emission originates from the circumnuclear disk, then we estimate that a redshifted feature at 1084 km/s in the spectrum should arise from a distance of 0.022 pc from the supermassive black hole (1.6 x 10(5) Schwarzschild radii), i.e. closer than the water maser emission previously detected at 22 GHz. This is only the second time 183 G...

  1. Measurements of intrinsic shot noise in a 35 GHz gyroklystron

    Calame, J. P.; Danly, B. G.; Garven, M.

    1999-07-01

    Experimental measurements of electron beam shot noise in a 35 GHz, 225 kW, three-cavity gyroklystron have been obtained from both the input and output cavities. This intrinsic noise was studied in the absence of an applied carrier (i.e., at zero drive power). The spectrum of the noise emitted by the input cavity is found to have a Lorentzian shape, with peak noise power densities from the input cavity typically reaching 6.3×10-15 W/Hz (-112 dBm/Hz), and typical 3 dB bandwidths of 160 MHz. The output cavity noise spectrum is found to be equal to the input cavity noise spectrum multiplied by the measured linear frequency response of the gyroklystron. The measured noise levels at the input cavity are 0-5 dB lower than theoretical predictions for shot noise unaltered by collective effects. Furthermore, the input cavity noise power exhibits complex variations as a function of beam current, beam velocity ratio, and circuit magnetic field that are not predicted by present theory. Noise-to-carrier ratios expected in the input cavity during full power amplifier operation are inferred from the noise measurements and known values of drive power required to saturate the gyroklystron. The noise-to-carrier ratio, with typical values of -90 to -80 dBc, is found to be a strong function of the operating parameters.

  2. MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey

    Jackson, J M; Foster, J B; Whitaker, J S; Sanhueza, P; Claysmith, C; Mascoop, J L; Wienen, M; Breen, S L; Herpin, F; Duarte-Cabral, A; Csengeri, T; Longmore, S; Contreras, Y; Indermuehle, B; Barnes, P J; Walsh, A J; Cunningham, M R; Brooks, K J; Britton, T R; Voronkov, M A; Urquhart, J S; Alves, J; Jordan, C H; Hill, T; Hoq, S; Finn, S; C., S; Bains, I; Bontemps, S; Bronfman, L; Caswell, J L; Deharveng, L; Ellingsen, S P; Fuller, G A; Garay, G; Green, J A; Hindson, L; Jones, P A; Lenfestey, C; Lo, N; Lowe, V; Mardones, D; Menten, K M; Minier, V; Morgan, L K; Motte, F; Muller, E; Peretto, N; Purcell, C R; Schilke, P; Schneider-Bontemps, N; Schuller, F; Titmarsh, A; Wyrowski, F; Zavagno, A

    2013-01-01

    The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope, MALT90 has obtained 3' x 3' maps toward ~2000 dense molecular clumps identified in the ATLASGAL 870 um Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to HII regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38") and spectral (0.11 km/s) resolution, the data reveal a wealth of information about the clump's morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and p...

  3. Centrifugal barrel polishing of 1.3 GHz Nb cavities

    Superconducting radio-frequency (SRF) cavities are the key components of particle accelerators such as the European X-ray Free Electron Laser (XFEL, under construction) and the planned future International Linear Collider (ILC). Steady progress in surface treatment techniques of SRF cavities in both the achievable quality factor Q and the accelerating electric field Eacc makes new accelerators and ambitious projects feasible. One of the alternative surface preparation techniques which is actually being explored is centrifugal barrel polishing (CBP) pioneered at KEK in Japan in mid-nineties by T. Hiuchi et al. CBP is a mechanical polishing of cavities and results in around 10 x smaller surface roughness and mirror-like surface as compared to chemistry alone. Q and Eacc are expected to be at least as high as for chemically treated cavities. CBP eliminates the bulk chemistry and has the potential to completely replace the chemistry. The University of Hamburg is installing a CBP machine to study it as a cavity preparation and repair technique for 9-cell 1.3 GHz SRF cavities at the Deutsche Elektronen-Synchrotron (DESY). The setup and first commissioning tests will be presented and discussed.

  4. A 20 GHz, 75 watt, helix TWT for space communications

    Heney, J. F.; Tamashiro, R. N.

    1983-01-01

    A space-qualified, helix-type traveling wave tube is being developed for satellite communication systems in the frequency band of 17.7 to 21.2 GHz. The design approach stresses very high efficiency operation, but with very low distortion. The tube provides multi-mode operation, permitting CW saturated power output levels of 75, 40, and 7.5 W. Operation is also anticipated at 5 dB below these saturation levels to achieve the required low distortion levels. Advanced construction features include a five-stage depressed collector, a diamond supported helix slow-wave circuit, and a type M dispenser cathode. High reliability and long life (10 yr) are objectives of the tube design. Preliminary test results on early developmental models of this tube are very encouraging. An output power of 75 to 90 W has been achieved over the full bandwidth with about 40 dB of saturated gain. More importantly, the basic electronic efficiency of the interaction process has been increased from about 7.5-11 percent by the use of the diamond helix support compared to earlier tubes using BeO support rods. This effort is supported by NASA Lewis Research Center and is aimed toward application in the NASA Advanced Communications Satellite Technology Program.

  5. An All-Optical Frequency Up/Down-Converter Utilizing Stimulated Brillouin Scattering In A Trf And Dcf For Rof Application

    N. A. Awang

    2011-09-01

    Full Text Available A frequency up and down conversion is proposed based on stimulated Brillouin scattering (SBS for Radio-over-fiber (RoF system. Microwave frequency up conversion from 2GHz to 12.5GHz and microwave frequency down conversion from 12.5GHz to 1.8GHz with largest Intermediate Frequency (IF power of -32dBm is successfully demonstrated. The up conversion is based on the 1st Stokes of Brillouin fiber laser in Truewave reach fiber (TWF and the down conversion is based on 1st AntiStokes of Brillouin fiber laser in Dispersion compensating fiber (DCF.

  6. An All-Optical Frequency Up/Down-Converter Utilizing Stimulated Brillouin Scattering In A Trf And Dcf For Rof Application

    N. A. Awang; H Ahmad; S. F. Norizan; M.Z. Zulkifli; Z.A. Ghani; S. W. Harun

    2011-01-01

    A frequency up and down conversion is proposed based on stimulated Brillouin scattering (SBS) for Radio-over-fiber (RoF) system. Microwave frequency up conversion from 2GHz to 12.5GHz and microwave frequency down conversion from 12.5GHz to 1.8GHz with largest Intermediate Frequency (IF) power of -32dBm is successfully demonstrated. The up conversion is based on the 1st Stokes of Brillouin fiber laser in Truewave reach fiber (TWF) and the down conversion is based on 1st AntiStokes of Brillouin...

  7. Measurements of the cosmic microwave background temperature at 1. 47 GHz

    Bensadoun, M.J.

    1991-11-01

    A radiofrequency-gain total power radiometer measured the intensity of the cosmic microwave background (CMB) at a frequency of 1.47 GHz (20.4 cm wavelength) from White Mountain, California, in September 1988 and from the South Pole, Antarctica, in December 1989. The CMB thermodynamic temperature, TCMB, is 2.27 {plus minus} 0.25 K (68% C.L.) measured from White Mountain and 2.26 {plus minus} 0.21 K from the South Pole site. The combined result is 2.27 {plus minus} 0.19 K. The correction for galactic emission has been derived from scaled low-frequency maps and constitutes the main source, of error. The atmospheric signal is found by extrapolation from zenith scan measurements at higher frequencies. The result is consistent with previous low-frequency measurements, including a measurement at 1.41 GHz (Levin et al. 1988) made with an earlier version of this instrument. The result is {approximately}2.5 {sigma} ({approximately}l% probability) from the 2.74 {plus minus} 0.02,K global average CMB temperature.

  8. Measurements of the cosmic microwave background temperature at 1.47 GHz

    Bensadoun, M.J.

    1991-11-01

    A radiofrequency-gain total power radiometer measured the intensity of the cosmic microwave background (CMB) at a frequency of 1.47 GHz (20.4 cm wavelength) from White Mountain, California, in September 1988 and from the South Pole, Antarctica, in December 1989. The CMB thermodynamic temperature, TCMB, is 2.27 {plus_minus} 0.25 K (68% C.L.) measured from White Mountain and 2.26 {plus_minus} 0.21 K from the South Pole site. The combined result is 2.27 {plus_minus} 0.19 K. The correction for galactic emission has been derived from scaled low-frequency maps and constitutes the main source, of error. The atmospheric signal is found by extrapolation from zenith scan measurements at higher frequencies. The result is consistent with previous low-frequency measurements, including a measurement at 1.41 GHz (Levin et al. 1988) made with an earlier version of this instrument. The result is {approximately}2.5 {sigma} ({approximately}l% probability) from the 2.74 {plus_minus} 0.02,K global average CMB temperature.

  9. A 3.16–7 GHz transformer-based dual-band CMOS VCO

    A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order (LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band (VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher quality-factor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18-μm CMOS technology and has 75% wide tuning range of 3.16–7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 mA. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are −122.5, −113.3, −110.1, and −116.8 dBc/Hz, respectively. The chip area, including the pads, is 1.2 × 0.62 mm2 and the supply voltage is 1.8 V. (paper)

  10. A quasioptical resonant-tunneling-diode oscillator operating above 200 GHz

    Brown, E. R.; Parker, C. D.; Molvar, K. M.; Calawa, A. R.; Manfra, M. J.

    1992-01-01

    We have fabricated and characterized a quasioptically stabilized resonant-tunneling-diode (RTD) oscillator having attractive performance characteristics for application as a radiometric local oscillator. The fundamental frequency of the oscillator is tunable from about 200 to 215 GHz, the instantaneous linewidth is between 10 and 20 kHz, and the output power across the tuning band is about 50 micro-W. The narrow linewidth and fine tuning of the frequency are made possible by a scanning semiconfocal open cavity which acts as the high-Q resonator for the oscillator. The cavity is compact, portable, and insensitive to vibration and temperature variation. The total dc power consumption (RTD plus bias supply) is only 10 mW. The present oscillator provides the highest power obtained to date from an RTD above 200 GHz. We attribute this partly to the use of the quasioptical resonator, but primarily to the quality of the RTD. It is fabricated from the In(0.53)Ga(0.47)As/AlAs materials system, which historically has yielded the best overall resonant-tunneling characteristics of any material system. The RTD active area is 4 sq microns, and the room-temperature peak current density and peak-to-valley current ratio are 2.5x10(exp 5) A cm(exp -2) and 9, respectively. The RTD is mounted in a WR-3 standard-height rectangular waveguide and is contacted across the waveguide by a fine wire that protrudes through a via hole in a Si3N4 'honeycomb' overlayer. We estimate that the theoretical maximum frequency of oscillation of this RTD is approximately 1.1 THz, and that scaled-down versions of the same quasioptical oscillator design should operate in a fundamental mode up to frequencies of at least 500 GHz.

  11. Optical frequency comb technology for ultra-broadband radio-frequency photonics

    Torres-Company, Victor; Weiner, Andrew M.

    2014-01-01

    The outstanding phase-noise performance of optical frequency combs has led to a revolution in optical synthesis and metrology, covering a myriad of applications, from molecular spectroscopy to laser ranging and optical communications. However, the ideal characteristics of an optical frequency comb are application dependent. In this review, the different techniques for the generation and processing of high-repetition-rate (>10 GHz) optical frequency combs with technologies compatible with opti...

  12. High frequency optical pulse generation by frequency doubling using polarization rotation

    Liu, Yang

    2016-05-01

    In this work, we propose and experimentally characterize a stable 40 GHz optical pulse generation by frequency doubling using polarization rotation in a phase modulator (PM). Only half the electrical driving frequency is required (i.e. 20 GHz); hence the deployment cost can be reduced. Besides, precise control of the bias of the PM is not required. The generated optical pulses have a high center-mode-suppression-ratio (CMSR) of  >  28 dB. The single sideband (SSB) noise spectrum is also measured, and the time-domain waveforms under different CMSRs are also analyzed and discussed.

  13. BICEP2 / Keck Array VI: Improved Constraints On Cosmology and Foregrounds When Adding 95 GHz Data From Keck Array

    Array, Keck; Ade, P A R; Ahmed, Z; Aikin, R W; Alexander, K D; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Bowens-Rubin, R; Brevik, J A; Buder, I; Bullock, E; Buza, V; Connors, J; Crill, B P; Duband, L; Dvorkin, C; Filippini, J P; Fliescher, S; Grayson, J; Halpern, M; Harrison, S; Hilton, G C; Hui, H; Irwin, K D; Karkare, K S; Karpel, E; Kaufman, J P; Keating, B G; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Megerian, K G; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Orlando, A; Pryke, C; Richter, S; Schwarz, R; Sheehy, C D; Staniszewski, Z K; Steinbach, B; Sudiwala, R V; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C; Turner, A D; Vieregg, A G; Weber, A C; Wiebe, D V; Willmert, J; Wong, C L; Wu, W L K; Yoon, K W

    2016-01-01

    We present results from an analysis of all data taken by the BICEP2 & Keck Array CMB polarization experiments up to and including that taken during the 2014 observing season. This includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes $Q$ and $U$ in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 GHz to 353 GHz. An excess over lensed-LCDM is detected at modest significance in the 95x150 $BB$ spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23x95, or for dust/sync correlation in spectra such as 23x353. We take the likelihood of all the spectra for a multi-component model including lensed-LCDM, dust, synchrotron and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio $...

  14. First Season QUIET Observations: Measurements of CMB Polarization Power Spectra at 43 GHz in the Multipole Range 25 <= ell <= 475

    Bischoff, C; Buder, I; Chinone, Y; Cleary, K; Dumoulin, R N; Kusaka, A; Monsalve, R; Næss, S K; Newburgh, L B; Reeves, R; Smith, K M; Wehus, I K; Zuntz, J A; Zwart, J T L; Bronfman, L; Bustos, R; Church, S E; Dickinson, C; Eriksen, H K; Ferreira, P G; Gaier, T; Gundersen, J O; Hasegawa, M; Hazumi, M; Huffenberger, K M; Jones, M E; Kangaslahti, P; Kapner, D J; Lawrence, C R; Limon, M; May, J; McMahon, J J; Miller, A D; Nguyen, H; Nixon, G W; Pearson, T J; Piccirillo, L; Radford, S J E; Readhead, A C S; Richards, J L; Samtleben, D; Seiffert, M; Shepherd, M C; Staggs, S T; Tajima, O; Thompson, K L; Vanderlinde, K; Williamson, R; Winstein, B

    2010-01-01

    The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43GHz and 95GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the CMB. QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, >10,000hours of data were collected, first with the 19-element 43GHz array (3458hours) and then with the 90-element 95GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ~1000deg^2. This paper reports initial results from the 43GHz receiver which has an array sensitivity to CMB fluctuations of 69uK sqrt(s). The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until th...

  15. Radio-frequency power generation

    Carter, Richard G.

    2013-01-01

    This paper reviews the main types of radio-frequency power amplifiers which are, or may be, used for high-power hadron accelerators. It covers tetrodes, inductive output tubes, klystrons and magnetrons with power outputs greater than 10 kW continuous wave or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for...

  16. ECRH in LDX with Many Microwave Frequencies

    Woskov, P.; Kesner, J.; Michael, P.; Garnier, D.; Mauel, M.; Davis, M.

    2010-11-01

    The large magnetic field range from 0.007 to 3.2 Tesla on closed flux surfaces around the LDX floating coil makes LDX uniquely capable of using many frequencies for electron cyclotron resonance heating (ECRH) to breakdown, build up, and sustain a core plasma. There are five sources installed with a combined injected power of 27 kW: two 2.45 GHz magnetrons at 2.5 and 1.9 kW, a 6.4 GHz, 2.5 kW klystron, a 10.5 GHz, 10 kW klystron, and a 28 GHz, 10 kW gyrotron. With all sources operating, D2 plasma density has increased to new highs near 10^18 m-3. Modeling with natural profiles shows strong ECRH absorption localized to discreet toroidal rings, each encompassing the plasma profile, that are located more inward with frequency. The relative size of the launched ECRH patterns to the absorption regions requires reflective trapping for complete absorption. Experimental observations show that higher frequencies are more efficient at generating density and lower frequencies are better at generating stored energy and energetic electrons.

  17. A low power, low noise figure quadrature demodulator for a 60 GHz receiver in 65-nm CMOS technology

    This paper presents the design of a low power (LP) and a low noise figure (NF) quadrature demodulator with an on-chip frequency divider for quadrature local oscillator (LO) signal generation. The transconductance stage of the mixer is implemented by an AC-coupled self-bias current reuse topology. On-chip series inductors are employed at the gate terminals of the differential input transconductance stage to improve the voltage gain by enhancing the effective transconductance. The chip is implemented in 65-nm LP CMOS technology. The demodulator is designed for an input radio frequency (RF) band ranging from 10.25 to 13.75 GHz. A fixed LO frequency of 12 GHz down-converts the RF band to an intermediate frequency (IF) band ranging from DC to 1.75 GHz. From 10 MHz to 1.75 GHz the demodulator achieves a voltage conversion gain (VCG) ranging from 14.2 to 13.2 dB, and a minimum single-sideband NF (SSB-NF) of 9 dB. The measured third-order input intercept point (IIP3) is −3.3 dBm for a two-tone test frequency spacing of 1 MHz. The mixer alone draws a current of only 2.5 mA, whereas the complete demodulator draws a current of 7.18 mA from a 1.2 V supply. The measurement results for a frequency divider, which was fabricated individually, prior to being integrated with the quadrature demodulator, in 65-nm LP CMOS technology, are also presented in this paper. (paper)

  18. EVN observations of eleven GHz-Peaked-Spectrum radio sources at 2.3/8.4GHz

    Xiang, L; Cassaro, P; Jiang, D; Reynolds, C

    2005-01-01

    We present results of EVN observations of eleven GHz-Peaked-Spectrum (GPS) radio sources at 2.3/8.4 GHz. These sources are from the classical ''bright'' GPS source samples with peak flux densities $>$ 0.2 Jy and spectral indices $\\alpha < -0.2$ ($S \\propto \

  19. A Three-Frequency Feed for Millimeter-Wave Radiometry

    Hoppe, Daniel J.; Khayatian, Behrouz; Sosnowski, John B.; Johnson, Alan K.; Bruneau, Peter J.

    2012-01-01

    A three-frequency millimeter-wave feed horn was developed as part of an advanced component technology task that provides components necessary for higher-frequency radiometers to meet the needs of the Surface Water and Ocean Topography (SWOT) mission. The primary objectives of SWOT are to characterize ocean sub-mesoscale processes on 10-km and larger scales in the global oceans, and to measure the global water storage in inland surface water bodies, including rivers, lakes, reservoirs, and wetlands. In this innovation, the feed provides three separate output ports in the 87-to- 97-GHz, 125-to-135-GHz, and 161-to-183- GHz bands; WR10 for the 90-GHz channel, WR8 for the 130-GHz channel, and WR5 for the 170-GHz channel. These ports are in turn connected to individual radiometer channels that will also demonstrate component technology including new PIN-diode switches and noise diodes for internal calibration integrated into each radiometer front end. For this application, a prime focus feed is required with an edge taper of approximately 20 dB at an illumination angle of 40 deg. A single polarization is provided in each band. Preliminary requirements called for a return loss of better than 15 dB, which is achieved across all three bands. Good pattern symmetry is also obtained throughout all three-frequency bands. This three-frequency broadband millimeter-wave feed also minimizes mass and provides a common focal point for all three millimeter-wave bands.

  20. How to improve the High Frequency capabilities of SRT

    Pisanu, T; Pernechele, C; Buffa, F; Vargiu, G

    2004-01-01

    The SRT (Sardinia Radio Telescope) is a general purpose, fully steerable, active surface equipped, 64 meters antenna, which is in an advanced construction state near Cagliari (Sardinia - Italy). It will be an antenna which could improve a lot the performances of the EVN network, particularly at frequencies higher than 22 GHz. The main antenna geometry consist of a shaped reflector system pair, based on the classical parabola-ellipse Gregorian configuration. It is designed to be able to operate with a good efficiency in a frequency range from 300 MHz up to 100 GHz. This frequency range, is divided in two parts which define also two antenna operational modes, one up to 22 GHz with a minimal amount of accessory instrumentation, and the other up to 100 GHz with a full complement of instrumentation. The goal is to make it possible to build a telescope operable up to 22 GHz, and then upgrade it at a future date to operate at frequencies up to 100 GHz. In order to get these goals, the SRT Metrology group is studying...

  1. Microwave frequency modulation in continuous-wave far-infrared ESR utilizing a quasioptical reflection bridge

    Nafradi, Balint; Gaal, Richard; Feher, Titusz; Forro, Laszlo

    2008-01-01

    We report the development of the frequency-modulation (FM) method for measuring electron spin resonance (ESR) absorption in the 210-420 GHz frequency range. We demonstrate that using a high-frequency ESR spectrometer without resonating microwave components enables us to overcome technical difficulties associated with the FM method due to nonlinear microwave-elements, without sacrificing spectrometer performance. FM was achieved by modulating the reference oscillator of a 13 GHz Phase Locked D...

  2. 35 GHz, 4-Cavity Gyroklystron Amplifier Experiment

    Garven, M.; Calame, J. P.; Danly, B. G.; Levush, B.; Wood, F.

    1998-11-01

    Gyroklystron amplifiers operating in the Ka-band are attractive sources for the next generation of millimeter wave radars and are currently under investigation at the Naval Research Laboratory (NRL). A four-cavity, 35 GHz gyroklystron experiment has been designed to demonstrate higher saturated gain (50dB) than previous experiments at NRL( J. J. Choi et al, IEEE Trans. Plasma Sci. 26(3), 416, 1998.). Non-linear, time-dependent simulations of the 4-cavity gyroklystron amplifier design using MAGYKL(P. E. Latham et al IEEE Trans. Plasma Sci. 22, 804, 1994.) predict 35% efficiency, 225 kW peak power, 50 dB saturated gain and a -3 dB bandwidth of 0.6%. For this four-cavity gyroklystron, the interaction between the TE_01 mode and a 70 kV, 9 A electron beam was studied with α=1.3 and an rms perpendicular velocity spread of 9%. Initial studies have shown that variations in magnetic field and voltage affect the trade-offs between power, bandwidth and efficiency. Theoretical design studies and experimental progress will be presented.

  3. [CI] 492 GHz mapping toward Cas A

    Mookerjea, B; Roshi, D A; Masur, M

    2006-01-01

    We have mapped the [C I] emission at 492 GHz toward the supernova remnant Cas A. We detect [C I] emission from the periphery of the diffuse Photon Dominated Region (PDR) covering the disk of Cas A, as traced by the carbon recombination lines, as well as from the denser PDRs associated with the molecular clouds towards the south-east. [C I] emission is detected from both the Perseus and Orion arm molecular clouds, with the -47 km s^-1 Perseus arm feature being strong enough to be detected at all positions. We estimate the C/CO relative abundance to be 0.2 at the position of the identified CO clouds and >1 for most of the cloud. Here we show that the distribution of [C I] emitting regions compared to the C+ region and molecular cloud is consistent with a scenario involving PDRs. Using physical models for PDRs we constrain the physical properties of the [C I] line-forming regions. We estimate the densities of the [C I] emitting regions to be between 10^2 and 10^3 cm^-3. Based on rather high volume filling factor...

  4. An Integrated 520-600 GHz Sub-Harmonic Mixer and Tripler Combination Based on GaAs MMIC Membrane Planar Schottky Diodes

    Thomas, B.; Gill, J.; Maestrini, A.; Lee, C.; Lin, R.; Sin, S.; Peralta, A.; Mehdi, I.

    2011-01-01

    We present here the design, development and test of an integrated sub-millimeter front-end featuring a 520-600 GHz sub-harmonic mixer and a 260-300 GHz frequency tripler in a single cavity. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional machined as well as silicon micro-machined blocks. Measurement results on the metal block give best DSB mixer noise temperature of 2360 K and conversion losses of 7.7 dB at 520 GHz. Preliminary results on the silicon micro-machined blocks give a DSB mixer noise temperature of 4860 K and conversion losses of 12.16 dB at 540 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer for both packages is between 30 and 50 mW

  5. First detection at 5.5 and 9 GHz of the radio relics in bullet cluster with ATCA

    Malu, Siddharth; Sandhu, Pritpal

    2016-01-01

    We present here results from observations at 5.5 and 9 GHz of the Bullet cluster 1E 0657-55.8 with the Australia Telescope Compact Array (ATCA). Our results show detection of diffuse emission in the cluster. Our findings are consistent with the previous observations by Shimwell et al. (2014) and Shimwell et al. (2015) at 1.1-3.1 GHz. Morphology of diffuse structures (relic regions A and B and the radio halo) are consistent with those reported by the previous study. Our results indicate steepening in the spectral index at higher frequencies (at and greater than 5.0 GHz) for region A. The spectrum can be fit well by a broken power law. We discuss the possibility of a few recent theoretical models explaining this break in the power law spectrum, and find that a modified Diffusive Shock Acceleration (DSA) model or a turbulent reacceleration model may be relevant. Deep radio observations at high frequencies (at and greater than 5 GHz) are required for a detailed comparison with this model.

  6. 3D Hot Test Simulations of a 220 GHz Folded Waveguide Traveling Wave Tube Using a CFDTD PIC Method

    Lin, Ming-Chieh; Song, Heather

    2015-11-01

    Millimeter or sub-THz wave sources centered at 220 GHz is of interest due to the potential for its commercial and military applications including high resolution radar, remote sensing, and high-data-rate communications. It has been demonstrated via 3D cold test finite element method (FEM) simulations that a folded waveguide traveling wave tube (FWTWT) can be designed and optimized at this frequency range with a small signal gain of 18 dB over a comparatively broad (-3 dB) bandwidth of ~ 10%. On the other hand, 3D hot test simulations of a V-band ladder TWT have been successfully demonstrated using a conformal finite-difference time-domain (CFDTD) particle-in-cell (PIC) method for center frequency of 50 GHz. In the present work, the 220 GHz FWTWT designs have been reviewed and studied. 3D Cold test simulations using both the CFDTD and FEM methods have been carried out and compared with each other as basis for 3D hot test CFDTD PIC simulations. The preliminary simulation result shows that the gain-bandwidth features at 220 GHz are achievable while carefully avoiding beam interceptions. Our study shows that the interaction characteristics are very sensitive to the operating beam parameters. Detail simulation results and discussions will be presented.

  7. Frequency-Tunable Microwave Field Detection in an Atomic Vapor Cell

    Horsley, Andrew

    2016-01-01

    We use an atomic vapor cell as a frequency tunable microwave field detector operating at frequencies from GHz to tens of GHz. We detect microwave magnetic fields from 2.3 GHz to 26.4 GHz, and measure the amplitude of the sigma+ component of an 18 GHz microwave field. Our proof-of-principle demonstration represents a four orders of magnitude extension of the frequency tunable range of atomic magnetometers from their previous dc to several MHz range. When integrated with a high resolution microwave imaging system, this will allow for the complete reconstruction of the vector components of a microwave magnetic field and the relative phase between them. Potential applications include near-field characterisation of microwave circuitry and devices, and medical microwave sensing and imaging.

  8. Non-Uniform Bias Enhancement of a Varactor-Tuned FSS used with a Low Profile 2.4 GHz Dipole Antenna

    Cure, David; Weller, Thomas M.; Miranda, Felix A.

    2012-01-01

    In this paper a low profile antenna using a nonuniformly biased varactor-tuned frequency selective surface (FSS) is presented. The tunable FSS avoids the use of vias and has a simplified DC bias network. The voltages to the DC bias ports can be varied independently allowing adjustment in the frequency response and enhanced radiation properties. The measured data demonstrate tunability from 2.15 GHz to 2.63 GHz with peak efficiencies that range from 50% to 90% and instantaneous bandwidths of 50 MHz to 280 MHz within the tuning range. The total antenna thickness is approximately lambda/45.

  9. Uso de la banda de 2,4 GHz según la regulación colombiana

    Roberto Cárdenas Castiblanco

    2010-12-01

    Full Text Available In this paper some calculus over 2, 4 GHz frequency band have been proposed, using the 802.11 standard and reviewing the fulfillment of current local official framework for this frequency band.The unlicensed frequency bands for telecommunications have been regulated by international and national agencies for over 30 years and nowadays they are 689.5 MHz of the radio electric spectrum. This regulation has allowed the emergence of low cost systems for mass consumption. This paper examines the calculation of links in these bands using the current Colombian regulations.

  10. The Q/U Imaging Experiment: Polarization Measurements of Radio Sources at 43 and 95 GHz

    Huffenberger, K M; Bischoff, C; Buder, I; Chinone, Y; Cleary, K; Kusaka, A; Monsalve, R; Næss, S K; Newburgh, L B; Reeves, R; Ruud, T M; Wehus, I K; Zwart, J T L; Dickinson, C; Eriksen, H K; Gaier, T; Gundersen, J O; Hasegawa, M; Hazumi, M; Miller, A D; Radford, S J E; Readhead, A C S; Staggs, S T; Tajima, O; Thompson, K L

    2014-01-01

    We present polarization measurements of extragalactic radio sources observed during the Cosmic Microwave Background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, $>$40 mJy catalog of the Australia Telescope (AT20G) survey. There are $\\sim$480 such sources within QUIET's four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30--40 mJy per Stokes parameter. At S/N $> 3$ significance, we detect linear polarization for seven sources in Q-band and six in W-band; only $1.3 \\pm 1.1$ detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization meas...

  11. Analysis of quasi-optical power combiners by vector field measurements at 150 GHz

    R. Judaschke

    2007-06-01

    Full Text Available A Two-dimensional quasi-optical power dividing/combining circuit has been experimentally investigated at 150 GHz. It consists of a rectangular horn antenna array as receiving/transmitting unit and a dual offset reflector setup to match the radiated field(s to the pattern of the receiving antenna(s. To verify both design and adjustment of the quasi-optical circuit, electric field scans have been performed in selected planes and volumes of the setup. To measure the spatial electric field distribution, a vector field measurement system has been developed which operates in the frequency range between 148 GHz and 152 GHz. Excellent agreement between calculated and measured results for a horn antenna array approve the predicted results calculated under the physical optics approximation. Measured power dividing/combining efficiency of the passive structure of 63% for an inter-element spacing of 10$ lambda$ indicates that the power combining principle is a suitable method up to submillimeter wavelengths.

  12. High power tests of an electroforming cavity operating at 11.424 GHz

    Dolgashev, V. A.; Gatti, G.; Higashi, Y.; Leonardi, O.; Lewandowski, J. R.; Marcelli, A.; Rosenzweig, J.; Spataro, B.; Tantawi, S. G.; Yeremian, D. A.

    2016-03-01

    The achievement of ultra high accelerating gradients is mandatory in order to fabricate compact accelerators at 11.424 GHz for scientific and industrial applications. An extensive experimental and theoretical program to determine a reliable ultra high gradient operation of the future linear accelerators is under way in many laboratories. In particular, systematic studies on the 11.424 GHz frequency accelerator structures, R&D on new materials and the associated microwave technology are in progress to achieve accelerating gradients well above 120 MeV/m. Among the many, the electroforming procedure is a promising approach to manufacture high performance RF devices in order to avoid the high temperature brazing and to produce precise RF structures. We report here the characterization of a hard high gradient RF accelerating structure at 11.424 GHz fabricated using the electroforming technique. Low-level RF measurements and high power RF tests carried out at the SLAC National Accelerator Laboratory on this prototype are presented and discussed. In addition, we present also a possible layout where the water-cooling of irises based on the electroforming process has been considered for the first time.

  13. High power tests of an electroforming cavity operating at 11.424 GHz

    The achievement of ultra high accelerating gradients is mandatory in order to fabricate compact accelerators at 11.424 GHz for scientific and industrial applications. An extensive experimental and theoretical program to determine a reliable ultra high gradient operation of the future linear accelerators is under way in many laboratories. In particular, systematic studies on the 11.424 GHz frequency accelerator structures, R and D on new materials and the associated microwave technology are in progress to achieve accelerating gradients well above 120 MeV/m. Among the many, the electroforming procedure is a promising approach to manufacture high performance RF devices in order to avoid the high temperature brazing and to produce precise RF structures. We report here the characterization of a hard high gradient RF accelerating structure at 11.424 GHz fabricated using the electroforming technique. Low-level RF measurements and high power RF tests carried out at the SLAC National Accelerator Laboratory on this prototype are presented and discussed. In addition, we present also a possible layout where the water-cooling of irises based on the electroforming process has been considered for the first time

  14. CBI limits on 31 GHz excess emission in southern HII regions

    Dickinson, C; Bronfman, L; Casassus, S; Davis, R J; Pearson, T J; Readhead, A C S; Wilkinson, P N

    2007-01-01

    We have mapped four regions of the southern Galactic plane at 31 GHz with the Cosmic Background Imager. From the maps, we have extracted the flux densities for six of the brightest \\hii regions in the southern sky and compared them with multi-frequency data from the literature. The fitted spectral index for each source was found to be close to the theoretical value expected for optically thin free-free emission, thus confirming that the majority of flux at 31 GHz is due to free-free emission from ionised gas with an electron temperature of $\\approx 7000-8000$ K. We also found that, for all six sources, the 31 GHz flux density was slightly higher than the predicted value from data in the literature. This excess emission could be due to spinning dust or another emission mechanism. Comparisons with $100 \\mu$m data indicate an average dust emissivity of $3.3\\pm1.7 mu$K (MJy/sr)$^{-1}$, or a 95 per cent confidence limit of $<6.1 \\mu$K (MJy/sr)$^{-1}$. This is lower than that found in diffuse clouds at high Gala...

  15. Quasi-optical log-periodic antenna SIS mixers for the 100 GHz band

    We designed and tested a quasi-optical SIS mixer that incorporates a substrate lens for the 100 GHz band. The mixer uses a planar self-complementary log-periodic antenna with an integrated tuning circuit. The antenna has a frequency independent impedance of around 114Ω over several octaves. The tuning circuit consists of two SIS junctions connected in parallel through a superconducting stripline inductor for tuning out the junction capacitances and a λ/4 impedance transformer for matching the junction resistance to the antenna impedance. The SIS junctions are Nb/AlOx/Nb and have an area of 10 μm2 and a current density of 1.7 kA cm-2 . The IF output from the mixer is brought out in a balanced way at each edge of the antenna, and is coupled to a cooled low-noise amplifier through a balun transformer by using a 180 deg. hybrid coupler. A double-sideband receiver noise temperature less than 130 K was measured from 85 to 110 GHz. The best noise temperature was 90 K at 101 GHz, which is the same as for waveguide receivers. (author)

  16. Initial Performance of BICEP3: A Degree Angular Scale 95 GHz Band Polarimeter

    Wu, W L K; Ahmed, Z; Alexander, K D; Amiri, M; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Bowens-Rubin, R; Buder, I; Bullock, E; Buza, V; Connors, J A; Filippini, J P; Fliescher, S; Grayson, J A; Halpern, M; Harrison, S A; Hilton, G C; Hristov, V V; Hui, H; Irwin, K D; Kang, J; Karkare, K S; Karpel, E; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Megerian, K G; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Pryke, C; Reintsema, C D; Richter, S; Sorensen, C; Staniszewski, Z K; Steinbach, B; Sudiwala, R V; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C E; Turner, A D; Vieregg, A G; Weber, A C; Wiebe, D V; Willmert, J; Yoon, K W

    2016-01-01

    BICEP3 is a $550~mm$ aperture telescope with cold, on-axis, refractive optics designed to observe at the $95~GHz$ band from the South Pole. It is the newest member of the BICEP/Keck family of inflationary probes specifically designed to measure the polarization of the cosmic microwave background (CMB) at degree-angular scales. BICEP3 is designed to house 1280 dual-polarization pixels, which, when fully-populated, totals to $\\sim$9$\\times$ the number of pixels in a single Keck $95~GHz$ receiver, thus further advancing the BICEP/Keck program's $95~GHz$ mapping speed. BICEP3 was deployed during the austral summer of 2014-2015 with 9 detector tiles, to be increased to its full capacity of 20 in the second season. After instrument characterization measurements were taken, CMB observation commenced in April 2015. Together with multi-frequency observation data from Planck, BICEP2, and the Keck Array, BICEP3 is projected to set upper limits on the tensor-to-scalar ratio to $r$ $\\lesssim 0.03$ at $95\\%$ C.L..

  17. Computer Aided Design and Analysis of a 2-4 GHz Broadband Balanced Microstrip Amplifier

    S. H. Ibrahim

    2012-07-01

    Full Text Available In this paper, a computer-aided design and analysis of a 2-4 GHz broadband balanced microstrip amplifier using a full computer simulation program developed by the author and others is presented. A short and efficient CAD procedure for broadband amplifier design is introduced. The first step is to design an initial narrow-band high gain microstrip amplifier at 3-GHz central frequency. The second step is to optimize the initial lengths and widths of the input and output microstrip-matching circuits to get the broadband amplifier over the range 2-4 GHz. The analysis of both narrow and broadband amplifiers is investigated. In addition, with the design and analysis of a low-pass microstrip filter, the paper introduces the design and analysis of a Lange coupler. The final AC schematic diagram of the designed amplifier with the lengths and widths of microstrip lines is presented.Key Words: Computer-Aided Design and Analysis, Microstrip Amplifier, Microwave Amplifier.

  18. Rain Attenuation at 58 GHz: Prediction versus Long-Term Trial Results

    Kvicera Vaclav

    2007-01-01

    Full Text Available Electromagnetic wave propagation research in frequency band 58 GHz was started at TESTCOM in Praha due to lack of experimentally obtained results needed for a realistic calculation of quality and availability of point-to-point fixed systems. Rain attenuation data obtained from a path at 58 GHz with V polarization located in Praha was processed over a 5-year period. Rainfall intensities have been measured by means of a heated siphon rain gauge. In parallel, rainfall intensity data from rain gauge records was statistically processed over the same year periods as the rain attenuation data. Cumulative distributions of rainfall intensities obtained as well as cumulative distributions of rain attenuation obtained are compared with the calculated ones in accordance with relevant ITU-R recommendations. The results obtained can be used as the primary basis for the possible extension of the ITU-R recommendation for calculating rain attenuation distributions up to 60 GHz. The obtained dependence of percentages of time of the average year on the percentages of time of the average worst month is also compared with the relevant ITU-R recommendation. The results obtained are discussed.

  19. Rain Attenuation at 58 GHz: Prediction versus Long-Term Trial Results

    Vaclav Kvicera

    2007-03-01

    Full Text Available Electromagnetic wave propagation research in frequency band 58 GHz was started at TESTCOM in Praha due to lack of experimentally obtained results needed for a realistic calculation of quality and availability of point-to-point fixed systems. Rain attenuation data obtained from a path at 58 GHz with V polarization located in Praha was processed over a 5-year period. Rainfall intensities have been measured by means of a heated siphon rain gauge. In parallel, rainfall intensity data from rain gauge records was statistically processed over the same year periods as the rain attenuation data. Cumulative distributions of rainfall intensities obtained as well as cumulative distributions of rain attenuation obtained are compared with the calculated ones in accordance with relevant ITU-R recommendations. The results obtained can be used as the primary basis for the possible extension of the ITU-R recommendation for calculating rain attenuation distributions up to 60 GHz. The obtained dependence of percentages of time of the average year on the percentages of time of the average worst month is also compared with the relevant ITU-R recommendation. The results obtained are discussed.

  20. Heater design and thermal analysis of cathode assembly for 170 GHZ, 1 MW gyrotron

    An activity of design and development of 170 GHz gyrotron is started at CEERI Pilani. 170 GHz is chosen ECRH frequency at ITER and total 24 MW of RF power generated from gyrotrons will be pumped into the ECRH system of ITER. This paper presents the design of toroid shape heater for dispenser cathode and the thermal analysis of complete cathode assembly for 3.2 MW triode type MIG for 170 GHz gyrotron. Finite element method based simulation tool ANSYS Work Banch (v.14.0) is used in the simulations. In the heater design, various electrical and geometrical parameters such as filament radius, number of turns, wire thickness, heater voltage, etc are optimized. The temperature on heater is optimized around 1600 °C considering the cathode temperature around 1100 °C. Tungsten is used as the filament material due to its excellent thermal properties. After the design of heater, thermal analysis is also performed for the complete cathode assembly. Various types of potting materials are also investigated. (author)

  1. A low power 20 GHz comparator in 90 nm COMS technology

    A low power 20 GHz CMOS dynamic latched regeneration comparator for ultra-high-speed, low-power analog-to-digital converters (ADCs) is proposed. The time constant in both the tracking and regeneration phases of the latch are analyzed based on the small signal model. A dynamic source-common logic (SCL) topology is adopted in the master-slave latch to increase the tracking and regeneration speeds. Implemented in 90 nm CMOS technology, this comparator only occupies a die area of 65 × 150 μm2 with a power dissipation of 14 mW from a 1.2 V power supply. The measurement results show that the comparator can work up to 20 GHz. Operating with an input frequency of 1 GHz, the circuit can oversample up to 20 Giga-sampling-per-second (GSps) with 5 bits resolution; while operating at Nyquist, the comparator can sample up to 20 GSps with 4 bits resolution. The comparator has been successfully used in a 20 GSps flash ADC and the circuit can be also used in other high speed applications. (semiconductor integrated circuits)

  2. A low power 20 GHz comparator in 90 nm COMS technology

    Kai, Tang; Qiao, Meng; Zhigong, Wang; Ting, Guo

    2014-05-01

    A low power 20 GHz CMOS dynamic latched regeneration comparator for ultra-high-speed, low-power analog-to-digital converters (ADCs) is proposed. The time constant in both the tracking and regeneration phases of the latch are analyzed based on the small signal model. A dynamic source-common logic (SCL) topology is adopted in the master-slave latch to increase the tracking and regeneration speeds. Implemented in 90 nm CMOS technology, this comparator only occupies a die area of 65 × 150 μm2 with a power dissipation of 14 mW from a 1.2 V power supply. The measurement results show that the comparator can work up to 20 GHz. Operating with an input frequency of 1 GHz, the circuit can oversample up to 20 Giga-sampling-per-second (GSps) with 5 bits resolution; while operating at Nyquist, the comparator can sample up to 20 GSps with 4 bits resolution. The comparator has been successfully used in a 20 GSps flash ADC and the circuit can be also used in other high speed applications.

  3. Wideband Dual-Frequency Dual-Polarized Dipole-Like Antenna

    Bao, Xiulong; Ammann, Max

    2011-01-01

    A wideband dual-frequency dual-polarized printed antenna is proposed for LTE, WLAN, and UWB systems. The dual-band antenna provides wide impedance bandwidths of 74% with respect to the center frequency of 2.725 GHz, and 39% with respect to the center frequency of 7.15 GHz. An open slot in the ground plane between the feed arms provides an orthogonal path to realize an embedded circularly polarized band at 2.35 GHz with an axial-ratio bandwidth of 16%. Dual-band characteristics are achieved by...

  4. Antipodal Linear Tapered Slot Antenna Based Radio Link Characterization in Narrow Hallway Environment at 60 GHz

    Shrivastava, Purva; Rao, T. Rama

    2016-05-01

    The performance of wireless communication systems is predominantly dependent on propagation environment and respective radiating antennas. Due to the shorter wavelength at millimeter wave (MmW) frequencies, the propagation loss through the objects in indoor environments is typically very high. To improve the channel capacity and to reduce inter-user interference, a high gain directional antenna is desired at MmW frequencies. Traditional antennas used in MmW devices are not suitable for low-cost commercial devices due to their heavy and bulky configurations. This paper focuses on design and development of a very compact (44.61 × 9.93 × 0.381 mm) high gain antipodal linear tapered slot antenna (ALTSA) utilizing substrate integrated waveguide (SIW) technology at 60 GHz. Received signal strength (RSS), path loss, and capacity are studied for MmW indoor applications utilizing ALTSA with radio frequency (RF) measurement equipment in narrow hallway environment.

  5. Multi-Gbit/s 60 GHz Transceiver Analysis Using FDM Architecture and Six-Port Circuit

    Nazih Khaddaj Mallat; Emilia Moldovan; Serioja O. Tatu; Ke Wu

    2011-01-01

    This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks (WLANs) operating at millimeter-wave frequencies. To obtain realistic simulation results, a six-port model based on the measurement results of a fabricated V-band hybrid coupler, the core component, is used. A frequency-division multiplexing scheme is used by introducing four quadrature phase-shift keying (QPSK) channels in the wireless communication link. The data rate achieved is about 4 Gbit/s. The operating frequency is in the 60-64 GHz unlicensed band. Bit error rate (BER) results are presented, and a comparison is made between single-carrier and multicarrier architectures. The proposed wireless system can be considered an efficient candidate for millimeter-wave communication systems operating at quasi-optical data rates.

  6. Antipodal Linear Tapered Slot Antenna Based Radio Link Characterization in Narrow Hallway Environment at 60 GHz

    Shrivastava, Purva; Rao, T. Rama

    2016-09-01

    The performance of wireless communication systems is predominantly dependent on propagation environment and respective radiating antennas. Due to the shorter wavelength at millimeter wave (MmW) frequencies, the propagation loss through the objects in indoor environments is typically very high. To improve the channel capacity and to reduce inter-user interference, a high gain directional antenna is desired at MmW frequencies. Traditional antennas used in MmW devices are not suitable for low-cost commercial devices due to their heavy and bulky configurations. This paper focuses on design and development of a very compact (44.61 × 9.93 × 0.381 mm) high gain antipodal linear tapered slot antenna (ALTSA) utilizing substrate integrated waveguide (SIW) technology at 60 GHz. Received signal strength (RSS), path loss, and capacity are studied for MmW indoor applications utilizing ALTSA with radio frequency (RF) measurement equipment in narrow hallway environment.

  7. Verification of scattering parameter measurements in waveguides up to 325 GHz including highly-reflective devices

    Schrader, T.; Kuhlmann, K.; Dickhoff, R.; Dittmer, J.; Hiebel, M.

    2011-07-01

    Radio-frequency (RF) scattering parameters (S-parameters) play an important role to characterise RF signal transmission and reflection of active and passive devices such as transmission lines, components, and small-signal amplifiers. Vector network analysers (VNAs) are employed as instrumentation for such measurements. During the last years, the upper frequency limit of this instrumentation has been extended up to several hundreds of GHz for waveguide measurements. Calibration and verification procedures are obligatory prior to the VNA measurement to achieve accurate results and/or to obtain traceability to the International System of Units (SI). Usually, verification is performed by measuring well-matched devices with known S-parameters such as attenuators or short precision waveguide sections (shims). In waveguides, especially above 110 GHz, such devices may not exist and/or are not traceably calibrated. In some cases, e.g. filter networks, the devices under test (DUT) are partly highly reflective. This paper describes the dependency of the S-parameters a) on the calibration procedure, b) on the applied torque to the flange screws during the mating process of the single waveguide elements. It describes further c) how highly-reflective devices (HRD) can be used to verify a calibrated VNA, and d) how a measured attenuation at several hundreds of GHz can be substituted by a well-known coaxial attenuation at 279 MHz, the intermediate frequency (IF) of the VNA, to verify the linearity. This work is a contribution towards traceability and to obtain knowledge about the measurement uncertainty of VNA instrumentation in the millimetre-wave range.

  8. Packaging of microwave integrated circuits operating beyond 100 GHz

    Samoska, L.; Daniel, E.; Sokolov, V.; Sommerfeldt, S.; Bublitz, J.; Olson, K.; Gilbert, B.; Chow, D.

    2002-01-01

    Several methods of packaging high speed (75-330 GHz) InP HEMT MMIC devices are discussed. Coplanar wirebonding is presented with measured insertion loss of less than 0.5dB and return loss better than -17 dB from DC to 110 GHz. A motherboard/daughterboard packaging scheme is presented which supports minimum loss chains of MMICs using this coplanar wirebonding method. Split waveguide block packaging approaches are presented in G-band (140-220 GHz) with two types of MMIC-waveguide transitions: E-plane probe andantipodal finline.

  9. An automated 55 GHz cryogenic Josephson sampling oscilloscope

    A computer-automated superconductive 55 GHz sampling oscilloscope based on 4 kA/cm2, Nb/Nb2O5/Pb edge Josephson junctions is presented. The Josephson sampler chip was flip-chip bonded to a carrier chip with a coplanar transmission line by use of a novel flip-chip bonding machine. A 5.6 ps step pulse was successfully coupled in to the transmission line and 18.5 GHz multiple reflections plus a parasitic oscillation at 43 GHz were observed

  10. Asymptotic entanglement transformation between W and GHZ states

    Vrana, Péter [Institute for Theoretical Physics, ETH Zürich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich (Switzerland); Department of Geometry, Budapest University of Technology and Economics, Egry József u. 1., 1111 Budapest (Hungary); Christandl, Matthias [Institute for Theoretical Physics, ETH Zürich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich (Switzerland); Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark)

    2015-02-15

    We investigate entanglement transformations with stochastic local operations and classical communication in an asymptotic setting using the concepts of degeneration and border rank of tensors from algebraic complexity theory. Results well-known in that field imply that GHZ states can be transformed into W states at rate 1 for any number of parties. As a generalization, we find that the asymptotic conversion rate from GHZ states to Dicke states is bounded as the number of subsystems increases and the number of excitations is fixed. By generalizing constructions of Coppersmith and Winograd and by using monotones introduced by Strassen, we also compute the conversion rate from W to GHZ states.

  11. 14/12-GHz-band satellite communication services

    Hayashi, Kunihiro; Nagaki, Kiyoaki; Mori, Yasuo

    1990-01-01

    Three new systems for integrated TV-relay services have been developed: Satellite Video Comunication Service (SVCS) and Satellite Digital Communication Service (SDCS), with Japan's 14/12-GHz-band commercial communication satellites. These systems have been in commercial use since May 1989. Usually SVCS and SDCS have been provided using Ka-band (30/20 GHz-band) of CS-2 and Cs-3. This paper provides an overview of the design, the performance, and the systems of the new 14/12-GHz-band satellite communication services.

  12. Tests of Low-Noise MMIC Amplifier Module at 290 to 340 GHz

    Gaier, Todd; Samoska, Lorene; Fung, King Man; Deal, William; Mei, Xiaobing; Lai, Richard

    2009-01-01

    A document presents data from tests of a low-noise amplifier module operating in the frequency range from 290 to 340 GHz said to be the highest-frequency low-noise, solid-state amplifier ever developed. The module comprised a three-stage monolithic microwave integrated circuit (MMIC) amplifier integrated with radial probe MMIC/waveguide transitions and contained in a compact waveguide package, all according to the concepts described in the immediately preceding article and in the referenced prior article, "Integrated Radial Probe Transition From MMIC to Waveguide" (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. The tests included measurements by the Y-factor method, in which noise figures are measured repeatedly with an input noise source alternating between an "on" (hot-load) condition and an "off" (cold-load) condition. (The Y factor is defined as the ratio between the "on" and "off" noise power levels.) The test results showed that, among other things, the module exhibited a minimum noise figure of about 8.7 dB at 325 GHz and that the gain at that frequency under the bias conditions that produced the minimum noise figure was between about 9 and 10 dB.

  13. A Microfabricated 8-40 GHz Dual-Polarized Reflector Feed

    Vanhille, Kenneth; Durham, Tim; Stacy, William; Karasiewicz, David; Caba, Aaron; Trent, Christopher; Lambert, Kevin; Miranda, Felix

    2014-01-01

    Planar antennas based on tightly coupled dipole arrays (also known as a current sheet antenna or CSA) are amenable for use as electronically scanned phased arrays. They are capable of performance nearing a decade of bandwidth. These antennas have been demonstrated in many implementations at frequencies below 18 GHz. This paper describes the implementation using a relatively new multi-layer microfabrication process resulting in a small, 6x6 element, dual-linear polarized array with beamformer that operates from 8 to 40 GHz. The beamformer includes baluns that feed the dual-polarized differential antenna elements and reactive splitter networks that also cover the full frequency range of operation. This antenna array serves as a reflector feed for a multi-band instrument designed to measure snow water equivalent (SWE) from airborne platforms. The instrument has both radar and radiome try capability at multiple frequencies. Scattering-parameter and time-domain measurements have been used to characterize the array feed. Radiation patterns of the antenna have been measured and are compared to simulation. To the best of the authors' knowledge, this work represents the most integrated multi-octave millimeter-wave antenna feed fabricated to date.

  14. The Development of 460 GHz gyrotrons for 700 MHz DNP-NMR spectroscopy

    Idehara, T.; Tatematsu, Y.; Yamaguchi, Y.; Khutoryan, E. M.; Kuleshov, A. N.; Ueda, K.; Matsuki, Y.; Fujiwara, T.

    2015-07-01

    Two demountable gyrotrons with internal mode converters were developded as sub-THz radiation sources for 700 MHz DNP (Dynamic Nuclear Polarization) enhanced NMR spectroscopy. Experimental study on the DNP-NMR spectroscopy will be carried out in Osaka University, Institute for Protein Research, as a collaboration with FIR UF. Both gyrotrons operate near 460 GHz and the output CW power measured at the end of transmission system made by circular waveguides is typically 20 to 30 watts. One of them named Gyrotron FU CW GVI (we are using "Gyrotron FU CW GO-1" as an official name in Osaka University) is designed to have a special function of high speed frequency modulation δ f within 100 MHz band. This will expand excitable band width of ESR and increase the number of electron spins contributing to DNP. The other gyrotron, Gyrotron FU CW GVIA ("Gyrotron FU CW GO-II") has a function of frequency tunability Δ f in the range of wider than 1.5 GHz, which is achieved in steady state by changing magnetic field intensity. This function should be used for adjusting the output frequency at the optimal value to achieve the highest enhancement factor of DNP.

  15. 160 GHz Gaussian beam microwave interferometry in low-density rf plasmas

    160 GHz Gaussian beam microwave interferometry is realized for electron density analysis in low pressure rf plasmas. Measurement of electron densities lower than 1016 m−3 with corresponding phase shift less than 0.3° demands high stability of the interferometer frequency and minimum disturbance due to external interfering voltages and mechanical vibrations of the optical components. The interferometer consists of a frequency stabilized (phase lock loop) heterodyne system operating at a frequency of fMWI = 160.28 GHz and wavelength of λMWI = 1.87 mm, respectively. A quasi-optical setup is used, considering specially designed horn antennas and elliptical mirrors as well as components which have to comply with the aperture limit in relation to the Gaussian microwave beam and its optimal coupling and focusing into the plasma center. A spatial and temporal resolution of about 10 mm (beam waist 5 mm) and 0.2 µs is achieved, respectively. In cc-rf plasma the lowest measurable phase shift is in the order of 0.01°, which corresponds to a line-integrated electron density of about 5 × 1013 m−2 or an electron density of 5 × 1014 m−3 averaged over the electrode diameter. Results are presented and discussed concerning line-integrated electron density in an asymmetric argon cc-rf plasma in dependence on rf power and total pressure. (paper)

  16. An RFI investigation for setting up a VLBI station below 2.8 GHz in Malaysia

    Abidin, Zamri Zainal; Ibrahim, Zainol Abidin; Rosli, Zulfazli; Malim, Siti Fatin Fathinah; Anim, Norsuzian Mohd; Noorazlan, Noorkhallaf

    2012-02-01

    In this paper, we investigated the radio frequency interference (RFI) that future Very Long Baseline Interferometer (VLBI) observations in Malaysia may encounter. Four frequency windows below 2.8 GHz were chosen for this study and their spectra were measured at four sites. The frequency windows are 322-328 MHz, 608-614 MHz, 1660-1660.5 MHz and 1660.5-1668.4 MHz. The measured averaged RFI floor noise levels in these windows are -99.992 (±0.570) dBm, -99.907 (±0.639) dBm, -100.220 (±0.4941) dBm and -100.359 (±0.110) dBm, respectively. We found that only two bands below 2.8 GHz are permitted for the purpose of radio astronomy in Malaysia. They are 608-614 MHz and 1660-1660.5 MHz. The RFI levels in these permissible bands at the best site (Langkawi) were also measured and concluded to be relatively low. Main sources of RFI in these bands in Malaysia were identified. We also reviewed several current VLBI observations in these two bands.

  17. Multi-resonance split ring resonator structures at sub-terahertz frequencies

    Galal, Hossam

    2016-01-01

    This paper reports on the computational development of novel architectures of multi-resonance Split Ring Resonators (SRRs), for efficient manipulation of Terahertz (THz) frequency beams. The conceived resonators are based on both a capacitive and inductive scheme. Simulation results have been obtained for a 60 GHz to 240 GHz operational bandwidth.

  18. Polarization structure of 12 gamma-ray quasars at 5 and 15 GHz

    Vetukhnovskaya, Yu. N.; Gabuzda, D. C.

    2012-12-01

    The results of dual-frequency polarization observations of 12 gamma-ray quasars are presented (as a continuation of a study of six blazars carried out earlier). The observations were obtained with the American Very Long Baseline Array. The distributions of intensity and polarization were obtained at 5 and 15 GHz. The degrees of polarization in the cores and jets of the 18 gamma-ray quasars do not stand out from those of other quasars. The brightness temperatures of the core components do not strongly exceed 1012 K.

  19. Air microwave yield (AMY): an experiment for measuring the GHz emission from air shower plasma

    The AMY experiment aim is to measure and characterize the microwave emission from plasmas induced in air by an electron beam. The study of this phenomenon could provide the development of new techniques for detecting high-energy cosmic rays over large area with a 100% duty cycle. We present the results of a first test beam done at the electron Beam Test Facility (BTF) of the Laboratori Nazionali di Frascati (LNF, Roma Italy) in November 2011. The measurements were performed with an electron beam of 510MeV energy. A frequency range between 1 and 20 GHz has been investigated.

  20. A 4-bit 7.5 GHz A/D Converter

    Tsenes, Petros; Uzunoglu, Nikolaos

    2003-01-01

    Based on a conventional flash architecture a 4-bit GaAs analog to digital (A/D) converter has been designed using OMMIC-Philips GaAs foundry and particularly its commercial enhancement/depletion mode 0.18 µm pHEMT technology process. The ADC operates at 7.5 GHz sampling rate with full power analog input bandwidth from DC to Nyquist frequency. Differential source coupled FET logic (SCFL) was used and the complexity of the whole chip is more than 1900 active devices. The converter can be used i...