Comparison of Stationarity Regions for Wireless Channels From 2 GHz to 30 GHz

DEFF Research Database (Denmark)

Yi, Tan; Wang, Chengxiang; Nielsen, Jesper Ødum

2017-01-01

Millimeter wave (mmWave) communication works in the frequencies above 6 gigahertz (GHz), with the system bandwidth up to 500 megahertz (MHz) or wider. In this case, the channel situations are dramatically different from the existing wireless channels in Third Generation/Fourth Generation (3G/4G...

Interference Mitigation Technique Using Active Spaceborne Sensor Antenna in EESS (Active) and Space Research Service (Active) for Use in 500 MHz Bandwidth Near 9.6 GHz

Science.gov (United States)

Huneycutt, Bryan L.

2005-01-01

This document presents an interference mitigation technique using the active spaceborne sensor SAR3 antenna in the Earth Exploration-Satellite Service (active) and Space Research Service (active) for use in a 500 MHz bandwidth near 9.6 GHz. The purpose of the document is present antenna designs which offer lower sidelobes and faster rolloff in the sidelobes which in turn mitigates the interference to other services from the EESS (active) and SRS (active) sensors.

High Dielectric Low Loss Transparent Glass Material Based Dielectric Resonator Antenna with Wide Bandwidth Operation

Science.gov (United States)

Mehmood, Arshad; Zheng, Yuliang; Braun, Hubertus; Hovhannisyan, Martun; Letz, Martin; Jakoby, Rolf

2015-01-01

This paper presents the application of new high permittivity and low loss glass material for antennas. This glass material is transparent. A very simple rectangular dielectric resonator antenna is designed first with a simple microstrip feeding line. In order to widen the bandwidth, the feed of the design is modified by forming a T-shaped feeding. This new design enhanced the bandwidth range to cover the WLAN 5 GHz band completely. The dielectric resonator antenna cut into precise dimensions is placed on the modified microstrip feed line. The design is simple and easy to manufacture and also very compact in size of only 36 × 28 mm. A -10 dB impedance bandwidth of 18% has been achieved, which covers the frequency range from 5.15 GHz to 5.95 GHz. Simulations of the measured return loss and radiation patterns are presented and discussed.

A new metasurface reflective structure for simultaneous enhancement of antenna bandwidth and gain

International Nuclear Information System (INIS)

Habib Ullah, M; Islam, M T

2014-01-01

A new bi-layered metasurface reflective structure (MRS) on a high-permittivity, low-loss, ceramic-filled, bio-plastic, sandwich-structured, dielectric substrate is proposed for the simultaneous enhancement of the bandwidth and gain of a dual band patch antenna. By incorporating the MRS with a 4 mm air gap between the MRS and the antenna, the bandwidth and gain of the dual band patch antenna are significantly enhanced. The reflection coefficient (S11 < −10 dB) bandwidth of the proposed MRS-loaded antenna increased by 240% (178%), and the average peak gain improved by 595% (128%) compared to the antenna alone in the lower (upper) band. Incremental improvements of the magnitude and directional patterns have been observed from the measured radiation patterns at the three resonant frequencies of 0.9 GHz, 3.7 GHz and 4.5 GHz. The effects of different configurations of the radiating patch and the ground plane on the reflection coefficient have been analyzed. In addition, the voltage standing wave ratio and input impedance have also been validated using a Smith chart. (paper)

A new metasurface reflective structure for simultaneous enhancement of antenna bandwidth and gain

Science.gov (United States)

Ullah, M. Habib; Islam, M. T.

2014-08-01

A new bi-layered metasurface reflective structure (MRS) on a high-permittivity, low-loss, ceramic-filled, bio-plastic, sandwich-structured, dielectric substrate is proposed for the simultaneous enhancement of the bandwidth and gain of a dual band patch antenna. By incorporating the MRS with a 4 mm air gap between the MRS and the antenna, the bandwidth and gain of the dual band patch antenna are significantly enhanced. The reflection coefficient (S11 < -10 dB) bandwidth of the proposed MRS-loaded antenna increased by 240% (178%), and the average peak gain improved by 595% (128%) compared to the antenna alone in the lower (upper) band. Incremental improvements of the magnitude and directional patterns have been observed from the measured radiation patterns at the three resonant frequencies of 0.9 GHz, 3.7 GHz and 4.5 GHz. The effects of different configurations of the radiating patch and the ground plane on the reflection coefficient have been analyzed. In addition, the voltage standing wave ratio and input impedance have also been validated using a Smith chart.

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

Directory of Open Access Journals (Sweden)

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

A polarization independent electromagnetically induced transparency-like metamaterial with large group delay and delay-bandwidth product

Science.gov (United States)

Bagci, Fulya; Akaoglu, Baris

2018-05-01

In this study, a classical analogue of electromagnetically induced transparency (EIT) that is completely independent of the polarization direction of the incident waves is numerically and experimentally demonstrated. The unit cell of the employed planar symmetric metamaterial structure consists of one square ring resonator and four split ring resonators (SRRs). Two different designs are implemented in order to achieve a narrow-band and wide-band EIT-like response. In the unit cell design, a square ring resonator is shown to serve as a bright resonator, whereas the SRRs behave as a quasi-dark resonator, for the narrow-band (0.55 GHz full-width at half-maximum bandwidth around 5 GHz) and wide-band (1.35 GHz full-width at half-maximum bandwidth around 5.7 GHz) EIT-like metamaterials. The observed EIT-like transmission phenomenon is theoretically explained by a coupled-oscillator model. Within the transmission window, steep changes of the phase result in high group delays and the delay-bandwidth products reach 0.45 for the wide-band EIT-like metamaterial. Furthermore, it has been demonstrated that the bandwidth and group delay of the EIT-like band can be controlled by changing the incidence angle of electromagnetic waves. These features enable the proposed metamaterials to achieve potential applications in filtering, switching, data storing, and sensing.

10 GHz frequency comb spectral broadening in AlGaAs-on-Insulator nano-waveguide with ultra-low pump power

DEFF Research Database (Denmark)

Hu, Hao; Pu, Minhao; Yvind, Kresten

2017-01-01

We experimentally demonstrated 10 GHz frequency comb spectral broadening with a 30-dB bandwidth of 238 nm in an 11-mm long AlGaAsOI nano-waveguide. The 10-GHz 230-fs pump pulse has an average power of only 12 mW.......We experimentally demonstrated 10 GHz frequency comb spectral broadening with a 30-dB bandwidth of 238 nm in an 11-mm long AlGaAsOI nano-waveguide. The 10-GHz 230-fs pump pulse has an average power of only 12 mW....

Preamplifier design with wide bandwidth using InGaP/GaAs HBT for 10-Gbps photoreceiver module

International Nuclear Information System (INIS)

Hong, S. E.; Lim, J. M.; Kim, S. I.; Nam, E. S.

2004-01-01

We report a preamplifier with wide bandwidth using high-speed and reliable InGaP/GaAs HBT applicable for 10-Gbps photoreceiver modules. The three-stage preamplifier with a negative feedback resistor demonstrates an effective transimpedance gain of 43 dBΩ, a -3-dB bandwidth of 14 GHz corresponding to a very high transimpedance-bandwidth product of 2.52 THzΩ, and an output return loss of -18 dB up to -3-dB bandwidth. This compact circuit is fabricated with an area of 800 X 700 μm 2 . A photoreceiver module of surface-mountable package type, that is composed of preamplifier and photodiode of surface-illumination type, demonstrates an optical bandwidth of 7.5 GHz at λ = 1.55 μ m and a 45-psec rise/fall time for 10-Gbps. The module shows higher sensitivity for a 10-Gbps optical transmission system.

Use of the 37-38 GHz and 40-40.5 GHz Ka-bands for Deep Space Communications

Science.gov (United States)

Morabito, David; Hastrup, Rolf

2004-01-01

This paper covers a wide variety of issues associated with the implementation and use of these frequency bands for deep space communications. Performance issues, such as ground station pointing stability, ground antenna gain, antenna pattern, and propagation effects such as due to atmospheric, charged-particle and space loss at 37 GHz, will be addressed in comparison to the 32 GHz Ka-band deep space allocation. Issues with the use of and competition for this spectrum also will be covered. The state of the hardware developed (or proposed) for operating in this frequency band will be covered from the standpoint of the prospects for achieving higher data rates that could be accommodated in the available bandwidth. Hardware areas to be explored include modulators, digital-to-analog converters, filters, power amplifiers, receivers, and antennas. The potential users of the frequency band will be explored as well as their anticipated methods to achieve the potential high data rates and the implications of the competition for bandwidth.

Micromachined On-Chip Dielectric Resonator Antenna Operating at 60 GHz

KAUST Repository

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.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

LFI 30 and 44 GHz receivers Back-End Modules

International Nuclear Information System (INIS)

Artal, E; Aja, B; Fuente, M L de la; Pascual, J P; Mediavilla, A; Martinez-Gonzalez, E; Pradell, L; Paco, P de; 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

2009-01-01

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: frequency response, effective bandwidth, equivalent noise temperature, 1/f noise and linearity are presented.

Bandwidth scalable, coherent transmitter based on the parallel synthesis of multiple spectral slices using optical arbitrary waveform generation.

Science.gov (United States)

Geisler, David J; Fontaine, Nicolas K; Scott, Ryan P; He, Tingting; Paraschis, Loukas; Gerstel, Ori; Heritage, Jonathan P; Yoo, S J B

2011-04-25

We demonstrate an optical transmitter based on dynamic optical arbitrary waveform generation (OAWG) which is capable of creating high-bandwidth (THz) data waveforms in any modulation format using the parallel synthesis of multiple coherent spectral slices. As an initial demonstration, the transmitter uses only 5.5 GHz of electrical bandwidth and two 10-GHz-wide spectral slices to create 100-ns duration, 20-GHz optical waveforms in various modulation formats including differential phase-shift keying (DPSK), quaternary phase-shift keying (QPSK), and eight phase-shift keying (8PSK) with only changes in software. The experimentally generated waveforms showed clear eye openings and separated constellation points when measured using a real-time digital coherent receiver. Bit-error-rate (BER) performance analysis resulted in a BER < 9.8 × 10(-6) for DPSK and QPSK waveforms. Additionally, we experimentally demonstrate three-slice, 4-ns long waveforms that highlight the bandwidth scalable nature of the optical transmitter. The various generated waveforms show that the key transmitter properties (i.e., packet length, modulation format, data rate, and modulation filter shape) are software definable, and that the optical transmitter is capable of acting as a flexible bandwidth transmitter.

Bandwidth enhancement of a microstrip patch antenna for ultra-wideband applications

Science.gov (United States)

Anum, Khanda; Singh, Milind Saurabh; Mishra, Rajan; Tripathi, G. S.

2018-04-01

The microstrip antennas are used where size, weight, cost, and performance are constraints. Microstrip antennas (MSA) are being used in many government and commercial applications among which it is mostly used in wireless communication. The proposed antenna is designed for Ultra-wideband (UWB), it is designed on FR4 substrate material with ɛr = 4.3 and 0.0025 loss tangent. The shape and size of patch in microstrip patch antenna plays an important role in its performance. In the proposed antenna design the respective changes have been introduced which includes slotting the feedline,adding a curved slot in patch and change in patch shape itself to improve the bandwidth of the conventional antenna. The simulated results of proposed antenna shows impedance bandwidth (defined by 10 dB return loss) of 2-11.1GHz, VSWRcommunication at 7.25-8.395 GHz.

Integrated 60GHz RF Beamforming in CMOS

NARCIS (Netherlands)

Yu, Yikun; Baltus, P.G.M.; Roermund, van A.H.M.

2011-01-01

The 60GHz band is promising for applications such as high-speed short-range wireless personal area network (WPAN), real time video streaming at rates of several Gbps, automotive radar, and mm-Wave imaging, since it provides a large amount of bandwidth that can freely (i.e. without a license) be used

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications.

Science.gov (United States)

Dong, Jian; Li, Qianqian; Deng, Lianwen

2017-02-10

Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR applications.

Influence of Reduced Graphene Oxide on Effective Absorption Bandwidth Shift of Hybrid Absorbers.

Science.gov (United States)

Ameer, Shahid; Gul, Iftikhar Hussain

2016-01-01

The magnetic nanoparticle composite NiFe2O4 has traditionally been studied for high-frequency microwave absorption with marginal performance towards low-frequency radar bands (particularly L and S bands). Here, NiFe2O4 nanoparticles and nanohybrids using large-diameter graphene oxide (GO) sheets are prepared via solvothermal synthesis for low-frequency wide bandwidth shielding (L and S radar bands). The synthesized materials were characterized using XRD, SEM, FTIR and microwave magneto dielectric spectroscopy. The dimension of these solvothermally synthesized pristine particles and hybrids lies within 30-58 nm. Microwave magneto-dielectric spectroscopy was performed in the low-frequency region in the 1 MHz-3 GHz spectrum. The as-synthesized pristine nanoparticles and hybrids were found to be highly absorbing for microwaves throughout the L and S radar bands (graphene sheet coupling shows application of these materials with absorption bandwidth which is tailored such that these could be used for low frequency. Previously, these were used for high frequency absorptions (typically > 4 GHz) with limited selective bandwidth.

Design of a 300 GHZ broadband coupler and RF-structure

International Nuclear Information System (INIS)

Krawczyk, F.L.; Carlsten, B.E.; Earley, L.M.; Sigler, F.E.; Potter, J.M.; Schulze, M.E.

2004-01-01

Recent LANL activities in millimeter wave structures focus on 95 and 300 GHz structures. They aim at power generation from low power (100W-2kW) with a round electron beam (120kV, 0.1-1.0 A) to high power (2-100 kW) with a sheet beam structure (120 kV, 20 A). Applications cover basic research, radar and secure communications and remote sensing of biological and chemical agents. In this presentation the design of a 300 GHz RF-structure with a broadband (> 6% bandwidth) power coupler is presented. The choice of two input/output waveguides, a special coupling region and the structure parameters are presented. As a benchmark also a scaled up version at 10 GHz was designed and measured. These results will also be presented. We are investigating planar micro-fabricated traveling-wave tube amplifiers as sources for the generation of millimeter waves from 95 to 300 GHz. While for low energy applications narrow structures with pencil beams are proposed, for high energy operation flat, thin sheet beams are required. For the latter vane-loaded rectangular waveguides that operate in a slow-wave mode matched to the velocity of the electron beam are especially well suited. The 300 GHz effort initially is limited to narrow structures for pencil beams. The main emphasis for this work are the study of fabrication issues and the understanding of features that allow a broadband operation (5-10% bandwidth).

Wide modulation bandwidth terahertz detection in 130 nm CMOS technology

Science.gov (United States)

Nahar, Shamsun; Shafee, Marwah; Blin, Stéphane; Pénarier, Annick; Nouvel, Philippe; Coquillat, Dominique; Safwa, Amr M. E.; Knap, Wojciech; Hella, Mona M.

2016-11-01

Design, manufacturing and measurements results for silicon plasma wave transistors based wireless communication wideband receivers operating at 300 GHz carrier frequency are presented. We show the possibility of Si-CMOS based integrated circuits, in which by: (i) specific physics based plasma wave transistor design allowing impedance matching to the antenna and the amplifier, (ii) engineering the shape of the patch antenna through a stacked resonator approach and (iii) applying bandwidth enhancement strategies to the design of integrated broadband amplifier, we achieve an integrated circuit of the 300 GHz carrier frequency receiver for wireless wideband operation up to/over 10 GHz. This is, to the best of our knowledge, the first demonstration of low cost 130 nm Si-CMOS technology, plasma wave transistors based fast/wideband integrated receiver operating at 300 GHz atmospheric window. These results pave the way towards future large scale (cost effective) silicon technology based terahertz wireless communication receivers.

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

DEFF Research Database (Denmark)

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...

Ultra-wideband and 60 GHz communications for biomedical applications

CERN Document Server

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

Influence of Reduced Graphene Oxide on Effective Absorption Bandwidth Shift of Hybrid Absorbers.

Directory of Open Access Journals (Sweden)

Shahid Ameer

Full Text Available The magnetic nanoparticle composite NiFe2O4 has traditionally been studied for high-frequency microwave absorption with marginal performance towards low-frequency radar bands (particularly L and S bands. Here, NiFe2O4 nanoparticles and nanohybrids using large-diameter graphene oxide (GO sheets are prepared via solvothermal synthesis for low-frequency wide bandwidth shielding (L and S radar bands. The synthesized materials were characterized using XRD, SEM, FTIR and microwave magneto dielectric spectroscopy. The dimension of these solvothermally synthesized pristine particles and hybrids lies within 30-58 nm. Microwave magneto-dielectric spectroscopy was performed in the low-frequency region in the 1 MHz-3 GHz spectrum. The as-synthesized pristine nanoparticles and hybrids were found to be highly absorbing for microwaves throughout the L and S radar bands ( 4 GHz with limited selective bandwidth.

A Reactance Compensated Three-Device Doherty Power Amplifier for Bandwidth and Back-Off Range Extension

Directory of Open Access Journals (Sweden)

Shichang Chen

2018-01-01

Full Text Available This paper proposes a new broadband Doherty power amplifier topology with extended back-off range. A shunted λ/4 short line or λ/2 open line working as compensating reactance is introduced to the conventional load modulation network, which greatly improves its bandwidth. Underlying bandwidth extension mechanism of the proposed configuration is comprehensively analyzed. A three-device Doherty power amplifier is implemented for demonstration based on Cree’s 10 W HEMTs. Measurements show that at least 41% drain efficiency is maintained from 2.0 GHz to 2.6 GHz at 8 dB back-off range. In the same operating band, saturation power is larger than 43.6 dBm and drain efficiency is higher than 53%.

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

DEFF Research Database (Denmark)

Beltrán, M.; Deng, Lei; Pang, Xiaodan

2012-01-01

, allowing the cost and energy efficiency of the system to be increased and supporting different users in the system. Four channels at 9.6 Gb/s/ch in 14.4-GHz bandwidth are generated and transmitted over up to 1.3-m wireless distance. The transmission of a 9.6-Gb/s single-channel signal occupying 3.2-GHz......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......-quadrature-amplitude-modulation OFDM signals is demonstrated with a bit error rate performance within the forward error correction limits. Signals of 19.1 Gb/s in 6.3-GHz bandwidth are transmitted over up to 1.3-m wireless distance. Optical comb generation is further employed to support different channels...

THz-bandwidth photonic Hilbert transformers based on fiber Bragg gratings in transmission.

Science.gov (United States)

Fernández-Ruiz, María R; Wang, Lixian; Carballar, Alejandro; Burla, Maurizio; Azaña, José; LaRochelle, Sophie

2015-01-01

THz-bandwidth photonic Hilbert transformers (PHTs) are implemented for the first time, to the best of our knowledge, based on fiber Bragg grating (FBG) technology. To increase the practical bandwidth limitation of FBGs (typically <200  GHz), a superstructure based on two superimposed linearly-chirped FBGs operating in transmission has been employed. The use of a transmission FBG involves first a conversion of the non-minimum phase response of the PHT into a minimum-phase response by adding an anticipated instantaneous component to the desired system temporal impulse response. Using this methodology, a 3-THz-bandwidth integer PHT and a fractional (order 0.81) PHT are designed, fabricated, and successfully characterized.

Arbitrary waveform modulated pulse EPR at 200 GHz

Science.gov (United States)

Kaminker, Ilia; Barnes, Ryan; Han, Songi

2017-06-01

We report here on the implementation of arbitrary waveform generation (AWG) capabilities at ∼200 GHz into an Electron Paramagnetic Resonance (EPR) and Dynamic Nuclear Polarization (DNP) instrument platform operating at 7 T. This is achieved with the integration of a 1 GHz, 2 channel, digital to analog converter (DAC) board that enables the generation of coherent arbitrary waveforms at Ku-band frequencies with 1 ns resolution into an existing architecture of a solid state amplifier multiplier chain (AMC). This allows for the generation of arbitrary phase- and amplitude-modulated waveforms at 200 GHz with >150 mW power. We find that the non-linearity of the AMC poses significant difficulties in generating amplitude-modulated pulses at 200 GHz. We demonstrate that in the power-limited regime of ω1 10 MHz) spin manipulation in incoherent (inversion), as well as coherent (echo formation) experiments. Highlights include the improvement by one order of magnitude in inversion bandwidth compared to that of conventional rectangular pulses, as well as a factor of two in improvement in the refocused echo intensity at 200 GHz.

Desain Antena Hexagonal Patch Array Berbasis Sistem Transfer Daya Wireless pada Frekuensi 2,4 GHz

Directory of Open Access Journals (Sweden)

Herma Nugroho R. A. K.

2016-06-01

Full Text Available Pada penelitian ini telah didesain antena hexagonal patch array yang dapat digunakan sebagai perangkat catu daya wireless. Antena hexagonal patch array ini didesain untuk menangkap gelombang radio (RF pada frekuensi 2,4 GHz yang dapat diaplikasikan sebagai antena pada Wireless Local Area Network (WLAN. Desain antena dilakukan menggunakan software CST Microwave studio, kemudian dilakukan pabrikasi dan pengukuran secara riil. Parameter pengujian antena hexagonal patch array meliputi return loss, Voltage Standing Wave Ratio (VSWR, gain, bandwidth, dan daya. Metode yang digunakan adalah pemodelan transmission line dan corporate feed line untuk pengaturan perubahan jarak antar patch antena. Perubahan variabel juga diteliti pengaruhnya terhadap parameter antena khususnya daya terima antena yang kemudian ditransmisikan ke rangkaian power harvester. Nilai parameter antena hasil simulasi menunjukkan nilai return loss adalah -33,38 dB, VSWR sebesar 1,041, gain sebesar 8,81 dBi, bandwidth adalah 0,084 GHz, daya sebesar 0,499 W (-3 dBm. Sedangkan parameter hasil pengukuran dari antena yang telah dipabrikasi adalah nilai return loss sebesar -33,21 dB, VSWR sebesar 1,048, gain sebesar 5 dBi, bandwidth adalah 0,145 GHz, daya sebesar -33 dBm.

Receiver bandwidth effects on complex modulation and detection using directly modulated lasers.

Science.gov (United States)

Yuan, Feng; Che, Di; Shieh, William

2016-05-01

Directly modulated lasers (DMLs) have long been employed for short- and medium-reach optical communications due to their low cost. Recently, a new modulation scheme called complex modulated DMLs has been demonstrated showing a significant optical signal to noise ratio sensitivity enhancement compared with the traditional intensity-only detection scheme. However, chirp-induced optical spectrum broadening is inevitable in complex modulated systems, which may imply a need for high-bandwidth receivers. In this Letter, we study the impact of receiver bandwidth effects on the performance of complex modulation and coherent detection systems based on DMLs. We experimentally demonstrate that such systems exhibit a reasonable tolerance for the reduced receiver bandwidth. For 10 Gbaud 4-level pulse amplitude modulation signals, the required electrical bandwidth is as low as 8.5 and 7.5 GHz for 7% and 20% forward error correction, respectively. Therefore, it is feasible to realize DML-based complex modulated systems using cost-effective receivers with narrow bandwidth.

Bandwidth enhancement of a dual band planar monopole antenna using meandered microstrip feeding.

Science.gov (United States)

Ahsan, M R; Islam, M T; Habib Ullah, M; Misran, N

2014-01-01

A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (ε r = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the -10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz-1 GHz) and at upper band is 28% (2.25 GHz-2.95 GHz). The measured maximum gains of -1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications.

Design of ultrathin dual-resonant reflective polarization converter with customized bandwidths

Science.gov (United States)

Kundu, Debidas; Mohan, Akhilesh; Chakrabarty, Ajay

2017-10-01

In this paper, an ultrathin dual-resonant reflective polarization converter is proposed to obtain customized bandwidths using precise space-filling technique to its top geometry. The unit cell of the dual-resonant prototype consists of conductive square ring with two diagonally arranged slits, supported by metal-backed thin dielectric layer. It offers two narrow bands with fractional bandwidths of 3.98 and 6.65% and polarization conversion ratio (PCR) of 97.16 and 98.87% at 4.52 and 6.97 GHz, respectively. The resonances are brought in proximity to each other by changing the length of surface current paths of the two resonances. By virtue of this mechanism, two polarization converters with two different types of bandwidths are obtained. One polarization converter produces a full-width at half-maxima PCR bandwidth of 34%, whereas another polarization converter produces a 90% PCR bandwidth of 19%. All the proposed polarization converters are insensitive to wide variations of incident angle for both TE- and TM-polarized incident waves. Measured results show good agreement with the numerically simulated results.

Fiber Wireless Transmission of 8.3 Gb/s/ch QPSK-OFDM Signals in 75-110 GHz Band

DEFF Research Database (Denmark)

Deng, Lei; Beltrán Ramírez, Marta; Pang, Xiaodan

2012-01-01

In this paper, we present a scalable high speed Wband (75-110 GHz) fiber wireless communication system. By using an optical frequency comb generator, 3-channel 8.3 Gb/s/ch optical orthogonal frequency division multiplexing (OOFDM) baseband signals in a 15 GHz bandwidth are seamlessly translated f...

Laboratory Heterodyne Spectrometers Operating at 100 and 300 GHZ

Science.gov (United States)

Maßen, Jakob; Wehres, Nadine; Hermanns, Marius; Lewen, Frank; Heyne, Bettina; Endres, Christian; Graf, Urs; Honingh, Netty; Schlemmer, Stephan

2017-06-01

Two new laboratory heterodyne emission spectrometers are presented that are currently used for high-resolution rotational spectroscopy of complex organic molecules. The room temperature heterodyne receiver operating between 80-110 GHz, as well as the SIS heterodyne receiver operating between 270-370 GHz allow access to two very important frequency regimes, coinciding with Bands 3 and 7 of the ALMA (Atacama Large Millimeter Array) telescope. Taking advantage of recent progresses in the field of mm/submm technology, we build these two spectrometers using an XFFFTS (eXtended Fast Fourier Transform Spectrometer) for spectral acquisition. The instantaneous bandwidth is 2.5 GHz in a single sideband, spread over 32768 channels. Thus, the spectral resolution is about 76 kHz per channel and thus comparable to high resolution spectra from telescopes. Both receivers are operated in double sideband mode resulting in a total instantaneous bandwidth of 5 GHz. The system performances, in particular the noise temperatures and stabilities are presented. Proof-of-concept is demonstrated by showing spectra of methyl cyanide obtained with both spectrometers. While the transition frequencies for this molecule are very well known, intensities of those transitions can also be determined with high accuracy using our new instruments. This additional information shall be exploited in future measurements to improve spectral predictions for astronomical observations. Other future prospects concern the study of more complex organic species, such as ethyl cyanide. These aspects of the new instruments as well as limitations of the two distinct receivers will be discussed.

Impact of crystal orientation on the modulation bandwidth of InGaN/GaN light-emitting diodes

Science.gov (United States)

Monavarian, M.; Rashidi, A.; Aragon, A. A.; Oh, S. H.; Rishinaramangalam, A. K.; DenBaars, S. P.; Feezell, D.

2018-01-01

High-speed InGaN/GaN blue light-emitting diodes (LEDs) are needed for future gigabit-per-second visible-light communication systems. Large LED modulation bandwidths are typically achieved at high current densities, with reports close to 1 GHz bandwidth at current densities ranging from 5 to 10 kA/cm2. However, the internal quantum efficiency (IQE) of InGaN/GaN LEDs is quite low at high current densities due to the well-known efficiency droop phenomenon. Here, we show experimentally that nonpolar and semipolar orientations of GaN enable higher modulation bandwidths at low current densities where the IQE is expected to be higher and power dissipation is lower. We experimentally compare the modulation bandwidth vs. current density for LEDs on nonpolar (10 1 ¯ 0 ), semipolar (20 2 ¯ 1 ¯) , and polar (" separators="|0001 ) orientations. In agreement with wavefunction overlap considerations, the experimental results indicate a higher modulation bandwidth for the nonpolar and semipolar LEDs, especially at relatively low current densities. At 500 A/cm2, the nonpolar LED has a 3 dB bandwidth of ˜1 GHz, while the semipolar and polar LEDs exhibit bandwidths of 260 MHz and 75 MHz, respectively. A lower carrier density for a given current density is extracted from the RF measurements for the nonpolar and semipolar LEDs, consistent with the higher wavefunction overlaps in these orientations. At large current densities, the bandwidth of the polar LED approaches that of the nonpolar and semipolar LEDs due to coulomb screening of the polarization field. The results support using nonpolar and semipolar orientations to achieve high-speed LEDs at low current densities.

Customer premise service study for 30/20 GHz satellite system

Science.gov (United States)

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.

160 Gbit/s photonics wireless transmission in the 300-500 GHz band

Directory of Open Access Journals (Sweden)

X. Yu

2016-11-01

Full Text Available To accommodate the ever increasing wireless traffic in the access networks, considerable efforts have been recently invested in developing photonics-assisted wireless communication systems with very high data rates. Superior to photonic millimeter-wave systems, terahertz (THz band (300 GHz-10 THz provides a much larger bandwidth and thus promises an extremely high capacity. However, the capacity potential of THz wireless systems has by no means been achieved yet. Here, we successfully demonstrate 160 Gbit/s wireless transmission by using a single THz emitter and modulating 25 GHz spaced 8 channels (20 Gbps per channel in the 300-500 GHz band, which is the highest bitrate in the frequency band above 300 GHz, to the best of our knowledge.

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

Science.gov (United States)

2010-10-01

... fundamental frequency following the provisions of § 15.31(m). (3) For systems operating in the 23.12-29.0 GHz... with the transmitter operating continuously at a fundamental frequency. The video bandwidth of the... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation of wideband vehicular radar systems...

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation.

Science.gov (United States)

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation

Science.gov (United States)

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

38.2-Gb/s Optical-Wireless Transmission in 75-110 GHz Based on Electrical OFDM with Optical Comb Expansion

DEFF Research Database (Denmark)

Deng, Lei; Pang, Xiaodan; Beltrán, Marta

2012-01-01

We demonstrate scalable optical comb- and heterodyning-based generation, optical and 1.3-m wireless transmission, and electrical heterodyne detection of multiband OFDM up to 38.2 Gb/s occupying 14.4-GHz RF bandwidth, for high-capacity optical-wireless links in 75-110 GHz....

On-chip patch antenna on InP substrate for short-range wireless communication at 140 GHz

DEFF Research Database (Denmark)

Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

2017-01-01

This paper presents the design of an on-chip patch antenna on indium phosphide (InP) substrate for short-range wireless communication at 140 GHz. The antenna shows a simulated gain of 5.3 dBi with 23% bandwidth at 140 GHz and it can be used for either direct chip-to-chip communication or chip...

Perancangan Dan Analisis Antena Mikrostrip Mimo Circular Pada Frekuensi 2.35 GHz Untuk Aplikasi LTE

Directory of Open Access Journals (Sweden)

Imam M.P Budi

2017-02-01

Full Text Available LTE (long Term Evolution merupakan teknologi komunikasi wireless generasi keempat yang saat ini sedang mengalami perkembangan. Salah satu perangkat yang sangat dibutuhkan pada teknologi tersebut adalah antenna. Teknik yang digunakan adalah teknik MIMO. Teknik MIMO menggunakan multiantena baik di sisi transmitter maupun di sisi receiver dengan koefisien korelasi di bawah 0.2. Untuk menghasilkan nilai koefisien korelasi di bawah 0.2, antena menggunakan ?/2 untuk jarak antar dua antena. Perancangan dan realisasi antena pada skripsi ini dipergunakan untuk aplikasi LTE yang bekerja pada frekuensi 2.3 GHz sampai 2.4 GHz. Simulasi antena menunjukkan frekuensi kerja yang direncanakan yaitu antara 2.3 GHz – 2.4 GHz, memiliki Return Loss -38.582 dB dan VSWR 1.0238 pada frekuensi tengah 2.350 MHz, gain sebesar 4.332 dBi. Hasil pengukuran antena satu terdapat pergeseran frekuensi dari 2.300 MHz - 2.400 MHz menjadi 2.310 - 2.384 MHz, antena  ini memiliki  Return  Loss -35.476 dB dan VSWR 1.034. Bandwidth 74 Mhz. Untuk antena dua terdapat pergeseran frekuensi menjadi 2.310 - 2.382 MHz, dengan Return  Loss -33.637 dB  dan VSWR  1.042. Bandwidth 72 MHz. Pada frekuensi 2.35 GHz gain sebesar 8 dBi dengan pola radiasi unidirectional dan polarisasi elips. Dari perancangan dan analisis tersebut, maka antena ini dapat digunakan sebagai antena teknologi LTE

125-GHz Microwave Signal Generation Employing an Integrated Pulse Shaper

DEFF Research Database (Denmark)

Liao, Shasha; Ding, Yunhong; Dong, Jianji

2017-01-01

We propose and experimentally demonstrate an on-chip pulse shaper for 125-GHz microwave waveform generation. The pulse shaper is implemented based on a silicon-on-insulator (SOI) platform that has a structure with eight-tap finite impulse response (FIR) and there is an amplitude modulator on each...... of the generated microwave waveforms is larger than 100 GHz, and it has wide bandwidth when changing the time delay of the adjacent taps and compactness, capability for integration with electronics and small power consumption are also its merits.......We propose and experimentally demonstrate an on-chip pulse shaper for 125-GHz microwave waveform generation. The pulse shaper is implemented based on a silicon-on-insulator (SOI) platform that has a structure with eight-tap finite impulse response (FIR) and there is an amplitude modulator on each...

High-fidelity polarization storage in a gigahertz bandwidth quantum memory

International Nuclear Information System (INIS)

England, D G; Michelberger, P S; Champion, T F M; Reim, K F; Lee, K C; Sprague, M R; Jin, X-M; Langford, N K; Kolthammer, W S; Nunn, J; Walmsley, I A

2012-01-01

We demonstrate a dual-rail optical Raman memory inside a polarization interferometer; this enables us to store polarization-encoded information at GHz bandwidths in a room-temperature atomic ensemble. By performing full process tomography on the system, we measure up to 97 ± 1% process fidelity for the storage and retrieval process. At longer storage times, the process fidelity remains high, despite a loss of efficiency. The fidelity is 86 ± 4% for 1.5 μs storage time, which is 5000 times the pulse duration. Hence, high fidelity is combined with a large time-bandwidth product. This high performance, with an experimentally simple setup, demonstrates the suitability of the Raman memory for integration into large-scale quantum networks. (paper)

Zero-Dispersion Slow Light with Wide Bandwidth in Photonic Crystal Coupled Waveguides

International Nuclear Information System (INIS)

Xiao-Yu, Mao; Geng-Yan, Zhang; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

2008-01-01

By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide (W 2 ) and the hole radii of the coupling region (r') will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity ν g in incident waveguide can be achieved. In particular, proper W 2 and r' can lead to the lowest ν g of 0.0085c at 1550 nm with wide bandwidth of 202 GHz for zero dispersion

3-D Printed Fabry–Pérot Resonator Antenna with Paraboloid-Shape Superstrate for Wide Gain Bandwidth

Directory of Open Access Journals (Sweden)

Qiang Chen

2017-11-01

Full Text Available A three-dimensional (3-D printed Fabry–Pérot resonator antenna (FPRA, which designed with a paraboloid-shape superstrate for wide gain bandwidth is proposed. In comparison with the commonly-adopted planar superstrate, the paraboloid-shape superstrate is able to provide multiple resonant heights and thus satisfy the resonant condition of the FPRA in a wide frequency band. A FPRA working at 6 GHz is designed, fabricated, and tested. Considering the fabrication difficulty caused by its complex structure, the prototype antenna was fabricated by using the 3-D printing technology, i.e., all components of the prototype antenna were printed with photopolymer resin and then treated by the surface metallization process. Measurement results agree well with the simulation results, and show the 3-D printed FPRA has a |S11| < −10 dB impedance bandwidth of 12.4%, and a gain of 16.8 dBi at its working frequency of 6 GHz. Moreover, in comparison with the planar superstrate adopted in traditional FPRAs, the paraboloid-shape superstrate of the proposed FPRA significantly improves the 3-dB gain bandwidth from 6% to 22.2%.

A 750MHz and a 8GHz High Bandwidth Digital FFT Spectrometer, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The scope of this project is to to develop a wide bandwidth, low power, and compact single board digital Fast Fourier Transform spectrometer (FFTS) optimized for the...

Design and Characterization of CMOS On-Chip Antennas for 60 GHz Communications

Directory of Open Access Journals (Sweden)

D.Titz

2012-04-01

Full Text Available In this paper, we present the design and the measurement of two antennas realized on a 130nm CMOS process. They both radiate in the 60 GHz band and are dedicated to Wireless Personal Area Network (WPAN applications. The antennas are manufactured within the frame of a multi-wafer project with several surrounding microelectronic circuits. The first antenna is an Inverted-F antenna (IFA. It has a maximum gain of -8 dBi and a -10 dB matching bandwidth of 20%. The second radiator is a meandered dipole. It has a maximum gain of -14 dBi and a -10 dB matching bandwidth of 10%. The challenging measurement of their reflection coefficient and their gain radiation pattern are presented. Simulated versus measured curves are analyzed. We especially demonstrate the necessity to take into account the closest microelectronic circuits of the antennas for accurate modeling of the radiating performance of 60 GHz on-chip dies.

Characterization of a 300-GHz Transmission System for Digital Communications

Science.gov (United States)

Hudlička, Martin; Salhi, Mohammed; Kleine-Ostmann, Thomas; Schrader, Thorsten

2017-08-01

The paper presents the characterization of a 300-GHz transmission system for modern digital communications. The quality of the modulated signal at the output of the system (error vector magnitude, EVM) is measured using a vector signal analyzer. A method using a digital real-time oscilloscope and consecutive mathematical processing in a computer is shown for analysis of signals with bandwidths exceeding that of state-of-the-art vector signal analyzers. The uncertainty of EVM measured using the real-time oscilloscope is open to analysis. Behaviour of the 300-GHz transmission system is studied with respect to various modulation schemes and different signal symbol rates.

A High Gain-Bandwidth Product Distributed Transimpedance Amplifier IC for High-Speed Optical Transmission Using Low-Cost GaAs Technology.

OpenAIRE

Giannini, F.; Limiti, E.; Orengo, G.; Serino, A.; De Dominicis, M.

2002-01-01

This paper reports a distributed baseband transimpedance amplifier for optical links up to 10 Gb/s. The amplifier operates as a baseband amplifier with a transimpedance gain of 48 dB Ω and a DC-to-9 GHz bandwidth. Some innovative design techniques to improve gain-bandwidth performance at low and high frequency with an available low-cost GaAs MESFET technology have been developed.

A mechanism for tuning 5 GHz HTS filters

Energy Technology Data Exchange (ETDEWEB)

Ohsaka, M.; Takeuchi, S.; Ono, S.; Lee, J.H.; Saito, A. [Department of Electrical Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan); Akasegawa, A.; Yamanaka, K.; Kurihara, K. [Fujitsu LTD., 10-1 Wakamiya, Morinosato, Atsugi, Kanagawa 243-0197 (Japan); Ohshima, S. [Department of Electrical Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)], E-mail: ohshima@yz.yamagata-u.ac.jp

2008-09-15

We developed a tuning mechanism of HTS filter with a dielectric tuning plate, dielectric trimming rods, and conducting trimming rods. The tuning plate has windows through which the dielectric and conducting trimming rods pass. The tuning plate was designed for a 3-pole filter with 5 GHz center frequency (f{sub c}) and 100 MHz bandwidth (BW) using a 3-dimensional electromagnetic simulator. We were able to shift the f{sub c} to frequencies below 500 MHz using the tuning plate with a dielectric constant of 45. However, the insertion loss (IL) and the pass-band ripple of the filter became more severe and the BW of the filter was narrower after tuning. We tried to improve the filter properties after tuning using the dielectric and conducting trimming rods. We decreased the IL and the pass-band ripple by adjusting the height of the dielectric trimming rods to above the resonators. Also, the BW was improved by using copper (Cu) trimming rods above the spaces between the resonators. The tuning plate and the trimming rods did not affect the IL. So, we simulated 500 MHz tuning without the filter properties deteriorating at f{sub c} = 5 GHz. Also, we experimentally evaluated that the f{sub c} could be shifted to 340 MHz using the dielectric plate, the pass-band ripple could be decreased by ripple trimming using the dielectric rods, and the BW could be increased 31 MHz by BW trimming using the Cu rods.

Electrically-driven GHz range ultrafast graphene light emitter (Conference Presentation)

Science.gov (United States)

Kim, Youngduck; Gao, Yuanda; Shiue, Ren-Jye; Wang, Lei; Aslan, Ozgur Burak; Kim, Hyungsik; Nemilentsau, Andrei M.; Low, Tony; Taniguchi, Takashi; Watanabe, Kenji; Bae, Myung-Ho; Heinz, Tony F.; Englund, Dirk R.; Hone, James

2017-02-01

Ultrafast electrically driven light emitter is a critical component in the development of the high bandwidth free-space and on-chip optical communications. Traditional semiconductor based light sources for integration to photonic platform have therefore been heavily studied over the past decades. However, there are still challenges such as absence of monolithic on-chip light sources with high bandwidth density, large-scale integration, low-cost, small foot print, and complementary metal-oxide-semiconductor (CMOS) technology compatibility. Here, we demonstrate the first electrically driven ultrafast graphene light emitter that operate up to 10 GHz bandwidth and broadband range (400 1600 nm), which are possible due to the strong coupling of charge carriers in graphene and surface optical phonons in hBN allow the ultrafast energy and heat transfer. In addition, incorporation of atomically thin hexagonal boron nitride (hBN) encapsulation layers enable the stable and practical high performance even under the ambient condition. Therefore, electrically driven ultrafast graphene light emitters paves the way towards the realization of ultrahigh bandwidth density photonic integrated circuits and efficient optical communications networks.

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

Science.gov (United States)

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.

Free space broad-bandwidth tunable laser diode based on Littman configuration for 3D profile measurement

Science.gov (United States)

Shirazi, Muhammad Faizan; Kim, Pilun; Jeon, Mansik; Kim, Chang-Seok; Kim, Jeehyun

2018-05-01

We developed a tunable laser diode for an optical coherence tomography system that can perform three-dimensional profile measurement using an area scanning technique. The tunable laser diode is designed using an Eagleyard tunable laser diode with a galvano filter. The Littman free space configuration is used to demonstrate laser operation. The line- and bandwidths of this source are 0.27 nm (∼110 GHz) and 43 nm, respectively, at the center wavelength of 860 nm. The output power is 20 mW at an operating current of 150 mA. A step height target is imaged using a wide-area scanning system to show the measurement accuracy of the proposed tunable laser diode. A TEM grid is also imaged to measure the topography and thickness of the sample by proposed tunable laser diode.

Broadband, large-area microwave antenna for optically detected magnetic resonance of nitrogen-vacancy centers in diamond

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Kento; Monnai, Yasuaki; Saijo, Soya; Fujita, Ryushiro; Ishi-Hayase, Junko; Itoh, Kohei M., E-mail: kitoh@appi.keio.ac.jp; Abe, Eisuke, E-mail: e-abe@keio.jp [School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Watanabe, Hideyuki [Correlated Electronics Group, Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

2016-05-15

We report on a microwave planar ring antenna specifically designed for optically detected magnetic resonance (ODMR) of nitrogen-vacancy (NV) centers in diamond. It has the resonance frequency at around 2.87 GHz with the bandwidth of 400 MHz, ensuring that ODMR can be observed under external magnetic fields up to 100 G without the need of adjustment of the resonance frequency. It is also spatially uniform within the 1-mm-diameter center hole, enabling the magnetic-field imaging in the wide spatial range. These features facilitate the experiments on quantum sensing and imaging using NV centers at room temperature.

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications

Directory of Open Access Journals (Sweden)

Jian Dong

2017-02-01

Full Text Available Ultrawideband (UWB antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT. A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36–4.16, 4.92–5.36, and 5.68–6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for

Linearizing of Low Noise Power Amplifier Using 5.8GHz Double Loop Feedforward Linearization Technique

Directory of Open Access Journals (Sweden)

Abdulkareem Mokif Obais

2017-05-01

Full Text Available In this paper, a double loop feedforward linearization technique is analyzed and built with a MMIC low noise amplifier “HMC753” as main amplifier and a two-stage class-A power amplifier as error amplifier. The system is operated with 5V DC supply at a center frequency of 5.8GHz and a bandwidth of 500MHz. The proposed technique, increases the linearity of the MMIC amplifier from 18dBm at 1dB compression point to more than 26dBm. In addition, the proposed system is tested with OFDM signal and it reveals good response in maximizing the linearity region and eliminating distortions. The proposed system is designed and simulated onAdvanced Wave Research-Microwave Office (AWR-MWO.

Tactical Decision Aids High Bandwidth Links Using Autonomous Vehicles

Science.gov (United States)

2004-01-01

1 Tactical Decision Aids (High Bandwidth Links Using Autonomous Vehicles ) A. J. Healey, D. P. Horner, Center for Autonomous Underwater Vehicle...SUBTITLE Tactical Decision Aids (High Bandwidth Links Using Autonomous Vehicles ) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Design of a 300 GHz Broadband TWT Coupler and RF-Structure

CERN Document Server

Krawczyk, F L

2004-01-01

Recent LANL activities in millimeter wave structures focus on 94 and 300 GHz structures. They aim at power generation from low power (100–2000 W) with a round electron beam (120 kV, 0.1–1.0 A) to high power (2–100 kW) with a sheet beam structure (120 kV, 20 A). Applications cover basic research, radar and secure communications and remote sensing of biological and chemical agents. In this presentation the design and cold-test measurements of a 300 GHz RF-structure with a broadband (>6% bandwidth) power coupler are presented. The design choice of two input/output waveguides, a special coupling region and the structure parameters themselves are presented. As a benchmark also a scaled up version at 10 GHz was designed and measured. These results will also be presented.

Accounting for binaural detection as a function of masker interaural correlation: effects of center frequency and bandwidth.

Science.gov (United States)

Bernstein, Leslie R; Trahiotis, Constantine

2014-12-01

Binaural detection was measured as a function of the center frequency, bandwidth, and interaural correlation of masking noise. Thresholds were obtained for 500-Hz or 125-Hz Sπ tonal signals and for the latter stimuli (noise or signal-plus-noise) transposed to 4 kHz. A primary goal was assessment of the generality of van der Heijden and Trahiotis' [J. Acoust. Soc. Am. 101, 1019-1022 (1997)] hypothesis that thresholds could be accounted for by the "additive" masking effects of the underlying No and Nπ components of a masker having an interaural correlation of ρ. Results indicated that (1) the overall patterning of the data depended neither upon center frequency nor whether information was conveyed via the waveform or by its envelope; (2) thresholds for transposed stimuli improved relative to their low-frequency counterparts as bandwidth of the masker was increased; (3) the additivity approach accounted well for the data across stimulus conditions but consistently overestimated MLDs, especially for narrowband maskers; (4) a quantitative approach explicitly taking into account the distributions of time-varying ITD-based lateral positions produced by masker-alone and signal-plus-masker waveforms proved more successful, albeit while employing a larger set of assumptions, parameters, and computational complexity.

110 GHz hybrid mode-locked fiber laser with enhanced extinction ratio based on nonlinear silicon-on-insulator micro-ring-resonator (SOI MRR)

International Nuclear Information System (INIS)

Liu, Yang; Hsu, Yung; Chow, Chi-Wai; Yang, Ling-Gang; Lai, Yin-Chieh; Yeh, Chien-Hung; Tsang, Hon-Ki

2016-01-01

We propose and experimentally demonstrate a new 110 GHz high-repetition-rate hybrid mode-locked fiber laser using a silicon-on-insulator microring-resonator (SOI MRR) acting as the optical nonlinear element and optical comb filter simultaneously. By incorporating a phase modulator (PM) that is electrically driven at a fraction of the harmonic frequency, an enhanced extinction ratio (ER) of the optical pulses can be produced. The ER of the optical pulse train increases from 3 dB to 10 dB. As the PM is only electrically driven by the signal at a fraction of the harmonic frequency, in this case 22 GHz (110 GHz/5 GHz), a low bandwidth PM and driving circuit can be used. The mode-locked pulse width and the 3 dB spectral bandwidth of the proposed mode-locked fiber laser are measured, showing that the optical pulses are nearly transform limited. Moreover, stability evaluation for an hour is performed, showing that the proposed laser can achieve stable mode-locking without the need for optical feedback or any other stabilization mechanism. (letter)

High capacity hybrid optical fiber-wireless links in 75–300GHz band

DEFF Research Database (Denmark)

Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

2014-01-01

Seamless convergence of fiber-optic and the wireless networks is of great interest for enabling transparent delivery of broadband services to users in different locations, including both metropolitan and rural areas. Current demand of bandwidth by end-users, especially using mobile devices......, is seeding the need to use bands located at the millimeter-wave region (30–300 GHz), mainly because of its inherent broadband nature. In our lab, we have conducted extensive research on high-speed photonic-wireless links in the W-band (75–110GHz). In this paper, we will present our latest findings...

Thin and Broadband Two-Layer Microwave Absorber in 4-12 GHz with Developed Flaky Cobalt Material

Science.gov (United States)

Gill, Neeraj; Singh, Jaydeep; Puthucheri, Smitha; Singh, Dharmendra

2018-03-01

Microwave absorbing materials (MAMs) in the frequency range of 2.0-18.0 GHz are essential for the stealth and communication applications. Researchers came up with effective MAMs for the higher frequency regions, i.e., 8.0-18.0 GHz, while absorbers with comparable properties in the lower frequency band are still not in the limelight. Designing a MAM for the lower frequency range is a critical task. It is known that the factors governing the absorption in this frequency predominantly depend on the permeability and conductivity of the material, whereas the shape anisotropy of the particles can initiate different absorption mechanisms like multiple internal reflections, phase cancellations, surface charge polarization and enhanced conductivity that can promote the microwave absorption towards lower frequencies. But the material alone may not serve the purpose of getting broad absorption bandwidth. With the effective use of advanced electromagnetic technique like multi-layering this problem may be solved. Therefore, in this paper, a material with shape anisotropy (cobalt flakes with high shape anisotropy) has been prepared and a two-layer structure is developed which gives the absorption bandwidth in 4.17-12.05 GHz at a coating thickness of 2.66 mm.

Pierce-Wiggler electron beam system for 250 GHz GYRO-BWO: Final report

International Nuclear Information System (INIS)

Pirkle, D.R.; Alford, C.W.; Anderson, M.H.; Garcia, R.F.; Legarra, J.R.; Nordquist, A.L.

1989-01-01

This final report summarizes the design and performance of the VUW-8028 Pierce-Wiggler electron beam systems, which can be used to power high frequency gyro-BWO's. The operator's manual for this gyro-BWO beamstick is included as appendix A. Researchers at Lawrence Livermore National Laboratory (LLNL) are developing a gyro-BWO with a center frequency of 250 GHz, 6% bandwidth, and 10 kV peak output power. The gyro-BWO will be used to drive a free electron laser amplifier at LLNL. The electron beam requirements of the gyro-BWO application are: Small beam size, .100 inch at 2500 gauss axial magnetic field; a large fraction of the electron energy in rotational velocity; ability to vary the electrons' axial velocity easily, for electronic tuning; and low velocity spread i.e. little variation in the axial velocities of the electrons in the interaction region. 1 ref., 13 figs

InP MMIC Chip Set for Power Sources Covering 80-170 GHz

Science.gov (United States)

Ngo, Catherine

2001-01-01

We will present a Monolithic Millimeter-wave Integrated Circuit (MMIC) chip set which provides high output-power sources for driving diode frequency multipliers into the terahertz range. The chip set was fabricated at HRL Laboratories using a 0.1-micrometer gate-length InAlAs/InGaAs/InP high electron mobility transistor (HEMT) process, and features transistors with an f(sub max) above 600 GHz. The HRL InP HEMT process has already demonstrated amplifiers in the 60-200 GHz range. In this paper, these high frequency HEMTs form the basis for power sources up to 170 GHz. A number of state-of-the-art InP HEMT MMICs will be presented. These include voltage-controlled and fixed-tuned oscillators, power amplifiers, and an active doubler. We will first discuss an 80 GHz voltage-controlled oscillator with 5 GHz of tunability and at least 17 mW of output power, as well as a 120 GHz oscillator providing 7 mW of output power. In addition, we will present results of a power amplifier which covers the full WRIO waveguide band (75-110 GHz), and provides 40-50 mW of output power. Furthermore, we will present an active doubler at 164 GHz providing 8% bandwidth, 3 mW of output power, and an unprecedented 2 dB of conversion loss for an InP HEMT MMIC at this frequency. Finally, we will demonstrate a power amplifier to cover 140-170 GHz with 15-25 mW of output power and 8 dB gain. These components can form a power source in the 155-165 GHz range by cascading the 80 GHz oscillator, W-band power amplifier, 164 GHz active doubler and final 140-170 GHz power amplifier for a stable, compact local oscillator subsystem, which could be used for atmospheric science or astrophysics radiometers.

Multi-gigabit wireless data transfer at 60 GHz

International Nuclear Information System (INIS)

Soltveit, H K; Schöning, A; Wiedner, D; Brenner, R

2012-01-01

In this paper we describe the status of the first prototype of the 60 GHz wireless Multi-gigabit data transfer topology currently under development at University of Heidelberg using IBM 130 nm SiGe HBT BiCMOS technology. The 60 GHz band is very suitable for high data rate and short distance applications. One application can be a wireless multi Gbps radial data transmission inside the ATLAS silicon strip detector, making a first level track trigger feasible. The wireless transceiver consists of a transmitter and a receiver. The transmitter includes an On-Off Keying (OOK) modulator, a Local Oscillator (LO), a Power Amplifier (PA) and a Band-pass Filter (BPF). The receiver part is composed of a Band-pass Filter (BPF), a Low Noise Amplifier (LNA), a double balanced down-convert Gilbert mixer, a Local Oscillator (LO), then a BPF to remove the mixer introduced noise, an Intermediate Amplifier (IF), an On-Off Keying demodulator and a limiting amplifier. The first prototype would be able to handle a data-rate of about 3.5 Gbps over a link distance of 1 m. The first simulations of the LNA show that a Noise figure (NF) of 5 dB, a power gain of 21 dB at 60 GHz with a 3 dB bandwidth of more than 20 GHz with a power consumption 11 mW are achieved. Simulations of the PA show an output referred compression point P1dB of 19.7 dB at 60 GHz.

Energy-efficient virtual optical network mapping approaches over converged flexible bandwidth optical networks and data centers.

Science.gov (United States)

Chen, Bowen; Zhao, Yongli; Zhang, Jie

2015-09-21

In this paper, we develop a virtual link priority mapping (LPM) approach and a virtual node priority mapping (NPM) approach to improve the energy efficiency and to reduce the spectrum usage over the converged flexible bandwidth optical networks and data centers. For comparison, the lower bound of the virtual optical network mapping is used for the benchmark solutions. Simulation results show that the LPM approach achieves the better performance in terms of power consumption, energy efficiency, spectrum usage, and the number of regenerators compared to the NPM approach.

100 GHz Externally Modulated Laser for Optical Interconnects Applications

DEFF Research Database (Denmark)

Ozolins, Oskars; Pang, Xiaodan; Iglesias Olmedo, Miguel

2017-01-01

We report on a 116 Gb/s on-off keying (OOK), four pulse amplitude modulation (PAM) and 105-Gb/s 8-PAM optical transmitter using an InP-based integrated and packaged externally modulated laser for high-speed optical interconnects with up to 30 dB static extinction ratio and over 100-GHz 3-d......B bandwidth with 2 dB ripple. In addition, we study the tradeoff between power penalty and equalizer length to foresee transmission distances with standard single mode fiber....

60 GHz Wireless Propagation Channels: Characterization, Modeling and Evaluation

OpenAIRE

Gustafson, Carl

2014-01-01

To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. A promising way to increase the amount of available spectrum is to utilize frequency bands in the mm-wave range of 30-300 GHz that previously have not been used for typical co...

A 94 GHz CMOS based oscillator transmitter with an on-chip meandered dipole antenna

KAUST Repository

Cheema, Hammad M.

2015-10-26

A miniaturized 94 GHz oscillator transmitter in 65nm CMOS is presented. An extremely small silicon foot-print of 0.25mm2 is achieved through meandering of the top-metal dipole antenna, conjugate matching between the oscillator and the antenna without impedance matching elements and efficient placement of the oscillator circuit within the antenna. The antenna demonstrates bandwidth of 90 to 99 GHz (10%) and a gain of -6dBi. The use of parasitic aware antenna-circuit code-sign strategy results in an accurate measured oscillation frequency of 94.1 GHz. The oscillator exhibits a measured output power of -25 dBm, phase noise of -88 dBc/Hz at 1 MHz offset and consumes 8.4mW from a 1V supply. © 2015 IEEE.

Integrated 1 GHz 4-channel InP phasar based WDM-receiver with Si bipolar frontend array

NARCIS (Netherlands)

Steenbergen, C.A.M.; Vreede, de L.C.N.; Dam, van C.; Scholtes, T.L.M.; Smit, M.K.; Tauritz, J.L.; Pedersen, J.W.; Moerman, I.; Verbeek, B.H.; Baets, R.G.F.

1995-01-01

An integrated 4-channel WDM-receiver frontend with 1 GHz channel bandwidth is described. The receiver consists of an integrated wavelength demultiplexer with photodiodes in InP technology connected through bond wires with a 4 channel Si bipolar transimpedance amplifier mounted on an epoxy board. The

VizieR Online Data Catalog: 22GHz image of 3C 273 (Bruni+, 2017)

Science.gov (United States)

Bruni, G.; Gomez, J. L.; Casadio, C.; Lobanov, A.; Kovalev, Y. Y.; Sokolovsky, K. V.; Lisakov, M. M.; Bach, U.; Marscher, A.; Jorstad, S.; Anderson, J. M.; Krichbaum, T. P.; Savolainen, T.; Vega-Garcia, L.; Fuentes, A.; Zensus, J. A.; Alberdi, A.; Lee, S.-S.; Lu, R.-S.; Perez-Torres, M.; Ros, E.

2017-07-01

A global ground array of 22 antennas was used to perform observations, including VLBA (Sc, Hn, Nl, Fd, La, Kp, Pt, Ov, Br, Mk), EVN (Hh, Mc, Nt, Tr, Jb, Ef, Ys), Long Baseline Array (-LBA- At, Mp, Ho, Cd), and two Kvazar antennas (Sv, Zc), plus Kalyazin (managed by ASC, Russia), and Green Bank (NRAO, USA). The observations took place on January 18-19, 2014, for a total of 16.8 hours, and at three different frequencies: 15GHz, 22GHz, and 43GHz. RA was involved only for the 22GHz part, while for the other bands only the VLBA was used. Both the Green Bank and Pushchino tracking station took part in the experiment. A RA-compatible total bandwidth of 32MHz, split into two 16-MHz IFs, was used. RA was scheduled to observe three consecutive 9.5 minute scans every 1.25 hours, to allow for antenna cooling. (2 data files).

Experimental evaluation of prefiltering for 56 Gbaud DP-QPSK signal transmission in 75 GHz WDM grid

DEFF Research Database (Denmark)

Borkowski, Robert; de Carvalho, Luis Henrique H.; Silva, Edson Porto da

2014-01-01

We investigate optical prefiltering for 56Gbaud (224Gbit/s) electrical time-division multiplexed (ETDM) dual polarization (DP) quaternary phase shift keying (QPSK) transmission. Different transmitter-side optical filter shapes are tested and their bandwidths are varied. Comparison of studied filter...... shapes shows an advantage of a pre-emphasis filter. Subsequently, we perform a fiber transmission of the 56Gbaud DP QPSK signal filtered with the 65GHz pre-emphasis filter to fit the 75GHz transmission grid. Bit error rate (BER) of the signal remains below forward error correction (FEC) limit after 300km...

Microphonics detuning compensation in 3.9 GHZ superconducting RF cavities

International Nuclear Information System (INIS)

Ruben Carcagno

2003-01-01

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

Microphonics detuning compensation in 3.9 GHZ superconducting RF cavities

Energy Technology Data Exchange (ETDEWEB)

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.

Optoelectronic time-domain characterization of a 100 GHz sampling oscilloscope

International Nuclear Information System (INIS)

Füser, H; Baaske, K; Kuhlmann, K; Judaschke, R; Pierz, K; Bieler, M; Eichstädt, S; Elster, C

2012-01-01

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

Chip design of a 5.8-GHz fractional-N frequency synthesizer with a tunable Gm−C loop filter

International Nuclear Information System (INIS)

Huang Jhin-Fang; Lai Wen-Cheng; Shin Chun-Wei; Hsu Chien-Ming; Liu Ron-Yi

2012-01-01

This paper proposes a novel G m −C loop filter instead of a conventional passive loop filter used in a phase-locked loop. The innovative advantage of the proposed architecture is tunable loop filter bandwidth and hence the process variations of passive elements of resistance R and capacitance C can be overcome and the chip area is greatly reduced. Furthermore, the MASH 1-1-1 sigma-delta (ΣΔ) modulator is adopted for performing the fractional division number and hence improves the phase noise as well. Measured results show that the locked phase noise is −114.1 dBc/Hz with lower G m −C bandwidth and −111.7 dBm/C with higher G m −C bandwidth at 1 MHz offset from carrier of 5.68 GHz. Including pads and built-in G m −C filter, the chip area of the proposed frequency synthesizer is 1.06 mm 2 . The output power is −8.69 dBm at 5.68 GHz and consumes 56 mW with an off-chip buffer from 1.8-V supply voltage. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

Energy Technology Data Exchange (ETDEWEB)

Li, X.; Zheng, C.; Pong, Philip W. T. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Zhou, Y., E-mail: yanzhou@hku.hk [School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Department of Physics, The University of Hong Kong (Hong Kong); Kubota, H.; Yuasa, S. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

2016-06-06

Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model. The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.

Broadband rectangular TEn0 mode exciter with H-plane power dividers for 100 GHz confocal gyro-devices.

Science.gov (United States)

Yao, Yelei; Wang, Jianxun; Li, Hao; Liu, Guo; Luo, Yong

2017-07-01

A generic approach to excite TE n0 (n ≥ 1) modes in a rectangular waveguide for confocal gyro-devices is proposed. The exciter consists of a 3 dB H-plane power divider (n ≥ 3) and a mode-converting section. The injection power is split into two in-phase signals with equal amplitudes which simultaneously excite the secondary waveguide via two sets of multiple slots. Both the position and width of the slot are symmetrically distributed with respect to the center line for each set of slots. The slot width complies with a geometry sequence, with adjacent slots being spaced a quarter wavelength apart to cancel the backward wave out. A TE 40 mode exciter at 100 GHz is numerically simulated and optimized, achieving a 1 dB and a 3 dB transmission bandwidth of 18.2 and 21 GHz, respectively. The prototype is fabricated and measured. The cold test is carried out utilizing two identical back-to-back connected mode exciters, and the measured performances are in good agreement with the numerical simulation results when taking into account the wall loss and assembly tolerance.

Bandwidth enhancement of monopole antenna with DGS for SHF and reconfigurable structure for WiMAX, WLAN and C-band applications

Science.gov (United States)

Beigi, P.; Mohammadi, P.

2017-11-01

In this study a reconfigurable antenna for WiMAX, WLAN, C-bands and SHF applications has been presented. The main body of antenna includes rectangular and L-shaped slotted ground plane and a rectangular patch with slotted feed line, for impedance bandwidth enhancement. In the proposed antenna, a PIN diode is used to adjust the frequency band to SHF, WiMAX, WLAN and C-bands applications. When PIN diode is forward-biased, the antenna covers the 3.5-31 GHz frequency range (i.e. a 160% bandwidth) and when the PIN diode is in its off-state, it operates between 3.4-5.8 GHz. The designed antenna, with a very small size of 12 × 18 × 1.6 mm3, has been fabricated and tested. The radiation pattern is approximately omnidirectional. Simulations and experimental results are in a good agreement with each other and suggest good performance for the presented antenna.

A Decade-Bandwidth Distributed Power Amplifier MMIC Using 0.25 μm GaN HEMT Technology

Directory of Open Access Journals (Sweden)

Dong-Hwan Shin

2017-10-01

Full Text Available This study presents a 2–20 GHz monolithic distributed power amplifier (DPA using a 0.25 μm AlGaN/GaN on SiC high electron mobility transistor (HEMT technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a nonuniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC are 35.3–38.6 dBm and 11.4%–31%, respectively, for 2–20 GHz.

Novel Radio Architectures for UWB, 60 GHz, and Cognitive Wireless Systems

Directory of Open Access Journals (Sweden)

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.

Indoor Corridor Wideband Radio Propagation Measurements and Channel Models for 5G Millimeter Wave Wireless Communications at 19 GHz, 28 GHz, and 38 GHz Bands

Directory of Open Access Journals (Sweden)

Ahmed M. Al-samman

2018-01-01

Full Text Available This paper presents millimeter wave (mmWave measurements in an indoor environment. The high demands for the future applications in the 5G system require more capacity. In the microwave band below 6 GHz, most of the available bands are occupied; hence, the microwave band above 6 GHz and mmWave band can be used for the 5G system to cover the bandwidth required for all 5G applications. In this paper, the propagation characteristics at three different bands above 6 GHz (19, 28, and 38 GHz are investigated in an indoor corridor environment for line of sight (LOS and non-LOS (NLOS scenarios. Five different path loss models are studied for this environment, namely, close-in (CI free space path loss, floating-intercept (FI, frequency attenuation (FA path loss, alpha-beta-gamma (ABG, and close-in free space reference distance with frequency weighting (CIF models. Important statistical properties, such as power delay profile (PDP, root mean square (RMS delay spread, and azimuth angle spread, are obtained and compared for different bands. The results for the path loss model found that the path loss exponent (PLE and line slope values for all models are less than the free space path loss exponent of 2. The RMS delay spread for all bands is low for the LOS scenario, and only the directed path is contributed in some spatial locations. For the NLOS scenario, the angle of arrival (AOA is extensively investigated, and the results indicated that the channel propagation for 5G using high directional antenna should be used in the beamforming technique to receive the signal and collect all multipath components from different angles in a particular mobile location.

Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

Energy Technology Data Exchange (ETDEWEB)

Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

2012-07-01

The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

Wideband Spectroscopy: The Design and Implementation of a 3 GHz Bandwidth, 8192 Channel, Polyphase Digital Spectrometer

Science.gov (United States)

Monroe, Ryan M.

2011-01-01

A family of state-of-the-art digital Fourier transform spectrometers has been developed, with a combination of high bandwidth and fine resolution unavailable elsewhere. Analog signals consisting of radiation emitted by constituents in planetary atmospheres or galactic sources are downconverted and subsequently digitized by a pair of interleaved Analog-to-Digital Converters, (ADC). This 6 Gsps (giga-sample per second) digital representation of the analog signal is then processed through an FPGA-based streaming Fast Fourier Transform (FFT), the key development described below. Digital spectrometers have many advantages over previously used analog spectrometers, especially in terms of accuracy and resolution, both of which are particularly important for the type of scientific questions to be addressed with next-generation radiometers. the implementation, results and underlying math for this spectrometer, as well as, potential for future extension to even higher bandwidth, resolution and channel orthogonality, needed to support proposed future advanced atmospheric science and radioastronomy, are discussed.

Performance characteristics of the 12 GHz, 200 watt Transmitter Experiment Package for CTS. [Communication Technology Satellite

Science.gov (United States)

Miller, E. F.; Fiala, J. L.; Hansen, I. G.

1975-01-01

Measured performance characteristics from ground test of the Transmitter Experiment Package (TEP) for the Communications Technology Satellite are presented. The experiment package consists of a 200 W Output Stage Tube (OST) powered by a Power Processing System (PPS). Descriptions of both the PPS and OST are given. The PPS provides the necessary voltages with a measured dc/dc conversion efficiency of 89 per cent. The OST, a traveling wave tube with multiple collectors, has a saturated rf output power of 224 W and operates at an overall efficiency exceeding 40 per cent over an 85 MHz bandwidth at 12 GHz. OST performance given includes frequency response, saturation characteristics, group delay, AM to PM conversion, intermodulation distortion, and two channel gain suppression. Single and dual channel FM video performance is presented. It was determined that for 12 MHz peak to peak frequency deviation on each channel, dual channel FM television signals can be transmitted through the TEP at 60 W, each channel, with 40 MHz channel spacing (center to center).

Improving microwave antenna gain and bandwidth with phase compensation metasurface

Directory of Open Access Journals (Sweden)

Ke Chen

2015-06-01

Full Text Available Metasurface, as a planar version of artificial metamaterial, provide an effective way to manipulate electromagnetic wave propagation. Here, we present a transparent metasurface for compensating the out-of-phase radiation from a microstrip patch antenna to improve its radiation gain and bandwidth. Based on the equivalence principle of Huygens’ surface, we propose metasurface composed of both inductive and capacitive resonant elements which could produce high transmission with variable phase characteristics. Such metasurface mounted on a patch antenna can transform the spherical-like phase profile generated from the patch into an in-phase planar one. A prototype antenna has been fabricated and validated the squeezed radiation pattern with suppressed sidelobes as well as enhanced impedance bandwidth due to strong near-field coupling. As operating at around 5.7 GHz, the proposed antenna may have potential application in wireless communication systems especially for point-to-point data transmission. It is believed that the design methodology could also be scaled to other frequency bands such as millimeter or terahertz wave.

Some fundamental problems relating to optical fibres. II. The ultimate bandwidth performance of optical fibre transmission lines

International Nuclear Information System (INIS)

Gambling, W.A.

1977-01-01

Optical fibre transmission lines can be divided broadly into two types, namely single mode and multimode. The bandwidth of the former is limited by the variation in group velocity with frequency caused by mode dispersion and material dispersion, with predicted values of tens of gigahertz over tens of kilometres for a monochromatic carrier, falling to approximately l GHz over 1km for a typical injection laser. Multimode fibres have the additional limitation of group delay between the various propagating modes. Several schemes have been suggested for reducing this effect, such as: (a) exciting only a few modes (ideally one) in a fibre exhibiting no mode conversion, (b) inducing coupling between bound modes but not into radiating modes, and (c) equalizing the mode velocities by means of a suitable refractive index profile. Most effort is presently being devoted to (c) and it has been shown that the optimum profile is affected by leaky modes and material dispersion. By operating at a wavelength in the region of 1.25μm the effect of material dispersion can be greatly reduced and bandwidths in excess of 1 GHz over 1km might be expected, even with sources of large linewidth. (author)

Observation of 45 GHz current waveforms using HTS sampler

International Nuclear Information System (INIS)

Maruyama, M.; Suzuki, H.; Hato, T.; Wakana, H.; Nakayama, K.; Ishimaru, Y.; Horibe, O.; Adachi, S.; Kamitani, A.; Suzuki, K.; Oshikubo, Y.; Tarutani, Y.; Tanabe, K.

2005-01-01

We succeeded in observing high-frequency current waveforms up to 45 GHz using a high-temperature superconducting (HTS) sampler. In this experiment, we used a sampler circuit with a superconducting pickup coil, which magnetically detects current signals flowing through a micro-strip line on a printed board placed outside the cryochamber. This type of measurement enables non-contact current-waveform observation that seems useful for analyses of EMI, defects in LSI, etc. Computer simulation reveals that one of our latest versions of HTS sampler circuits having Josephson transmission lines with optimized biases as buffers has a potential of sampling high-frequency signals with a bandwidth above 100 GHz. To realize the circuit parameters required in the simulations, we developed an HTS circuit fabrication process employing a lower ground plane structure with SrSnO 3 insulating layers. We consider that improvement of the circuit fabrication process and optimization of the pickup coil lead to much higher signal frequency observable by the sampler

Sub-GHz-resolution C-band Nyquist-filtering interleaver on a high-index-contrast photonic integrated circuit.

Science.gov (United States)

Zhuang, Leimeng; Zhu, Chen; Corcoran, Bill; Burla, Maurizio; Roeloffzen, Chris G H; Leinse, Arne; Schröder, Jochen; Lowery, Arthur J

2016-03-21

Modern optical communications rely on high-resolution, high-bandwidth filtering to maximize the data-carrying capacity of fiber-optic networks. Such filtering typically requires high-speed, power-hungry digital processes in the electrical domain. Passive optical filters currently provide high bandwidths with low power consumption, but at the expense of resolution. Here, we present a passive filter chip that functions as an optical Nyquist-filtering interleaver featuring sub-GHz resolution and a near-rectangular passband with 8% roll-off. This performance is highly promising for high-spectral-efficiency Nyquist wavelength division multiplexed (N-WDM) optical super-channels. The chip provides a simple two-ring-resonator-assisted Mach-Zehnder interferometer, which has a sub-cm2 footprint owing to the high-index-contrast Si3N4/SiO2 waveguide, while manifests low wavelength-dependency enabling C-band (> 4 THz) coverage with more than 160 effective free spectral ranges of 25 GHz. This device is anticipated to be a critical building block for spectrally-efficient, chip-scale transceivers and ROADMs for N-WDM super-channels in next-generation optical communication networks.

Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions

Science.gov (United States)

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

Eight-Element Antenna Array for LTE 3.4-3.8 GHz Mobile Handset Applications

Science.gov (United States)

Yang, Lingsheng; Ji, Ming; Cheng, Biyu; Ni, Bo

2017-05-01

In this letter, an eight-element Multiple-input multiple-output (MIMO) antenna system for LTE mobile handset applications is proposed. The antenna array consists of eight 3D inverted F-shaped antennas (3D-IFA), and the measured -10 dB impedance bandwidth is 3.2-3.9 GHz which can cover the LTE bands 42 and 43 (3.4-3.8 GHz). By controlling the rotation of the antenna elements, no less than 10 dB isolation between antenna elements can be obtained. After using the specially designed meandered slots on the ground as decoupling structures, the measured isolation can be further improved to higher than 13 dB between the antenna elements at the whole operating band.

Traveling-Wave Maser for 32 GHz

Science.gov (United States)

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

FRB121102: First detection across 5 - 8 GHz and spectral properties from the Breakthrough Listen instrument

Science.gov (United States)

Gajjar, Vishal; Siemion, Andrew; MacMohan, David; Croft, Steve; Hellbourg, Greg; Isaacson, Howard; Enriquez, J. Emilio; Price, Daniel; Lebofsky, Matt; De Boer, David; Werthimer, Dan; Hickish, Jack; Brinkman, Casey; Chatterjee, Shami; Ransom, Scott M.; Law, Casey; Hessels, Jason W. T.; Cordes, Jim; Spitler, Laura; Lynch, Ryan; McLaughlin, Maura; Scholz, Paul; Marcote, Benito; Bower, Geoffrey C.; Tendulkar, Shriharsh

2018-01-01

Fast Radio Bursts (FRBs) are some of the most energetic and enigmatic events in the Universe. The origin of these sources is among the most challenging questions of modern-day astrophysics. Thus, it is imperative to understand the properties of these bursts across a range of radio frequencies. Among the known FRBs, FRB121102 is the only source known to show repeated bursts [Spitler et al., Nature, 531, 7593 202-205, 2016], which can allow a detailed investigation of various origin models. In August 2017, we initiated a campaign observing FRB 121102 using the Breakthrough Listen Digital Backend with the C-band receiver at the Robert C. Byrd Green Bank Telescope (GBT). We recorded baseband voltage data across 5.4 GHz of bandwidth, completely covering the C-band receiver's nominal 4-8 GHz band [MacMahon et al. arXiv:1707.06024v2]. The recorded data were searched for dispersed pulses consistent with the known dispersion measure of FRB 121102 (557 pc cm-3) using high-speed GPU software tools. We detected 21 bursts above our detection threshold of 6 sigmas in the first 60-minutes, out of which 18 occurred in the first 30-minutes only. To our knowledge, this is the highest event rate seen for FRB121102 at any observing frequency. These observations are the highest frequency and widest bandwidth detection of bursts from FRB 121102 (or any other FRB) obtained to-date. We note that individual bursts show marked changes in spectral extent ranging from hundreds of MHz to several GHz. We have used high frequency dynamic spectra of these bursts to estimate the characteristic scintillation bandwidth and correlation time-scale. We also found distinctive temporal structures, separated by a few milliseconds, in three of the strongest bursts, with each sub-structure exhibiting varied spectral features. We will discuss our findings and how these detections of FRB 121102 around 8 GHz opens up a new regime in scrutinizing various origin models. We will also highlight the unique

Design and Measurement of a 2.45 Ghz On-Body Antenna Optimized for Hearing Instrument Applications

DEFF Research Database (Denmark)

Kvist, Søren Helstrup; Jakobsen, Kaj Bjarne; Thaysen, Jesper

2012-01-01

A balanced PIFA-inspired antenna design is presented for use with the 2:45 GHz ear-to-ear radio channel. The antenna is designed such that the radiated electric fields are primarily polarized normal to the surface of the head, in order to obtain a high on-body path gain (jS21 j). The antenna...... structure can be made conformal to the outer surface of a hearing instrument, such that the bandwidth of the antenna is optimized given the available volume. The radiation patterns, ear-to-ear path gain and available bandwidth is measured and compared to the simulated results. It is found that the antenna...

Beam-Steering Performance of Flat Luneburg Lens at 60 GHz for Future Wireless Communications

Directory of Open Access Journals (Sweden)

Robert Foster

2017-01-01

Full Text Available The beam-steering capabilities of a simplified flat Luneburg lens are reported at 60 GHz. The design of the lens is first described, using transformation electromagnetics, before discussion of the fabrication of the lens using casting of ceramic composites. The simulated beam-steering performance is shown, demonstrating that the lens, with only six layers and a highest permittivity of 12, achieves scan angles of ±30° with gains of at least 18 dBi over a bandwidth from 57 to 66 GHz. To verify the simulations and further demonstrate the broadband nature of the lens, raw high definition video was transmitted over a wireless link at scan angles up to 36°.

GHz modulation enabled using large extinction ratio waveguide-modulator integrated with 404 nm GaN laser diode

KAUST Repository

Shen, Chao

2017-01-30

A 404-nm emitting InGaN-based laser diode with integrated-waveguide-modulator showing a large extinction ratio of 11.3 dB was demonstrated on semipolar (2021) plane GaN substrate. The device shows a low modulation voltage of −2.5 V and ∼ GHz −3 dB bandwidth, enabling 1.7 Gbps data transmission.

GHz modulation enabled using large extinction ratio waveguide-modulator integrated with 404 nm GaN laser diode

KAUST Repository

Shen, Chao; Lee, Changmin; Ng, Tien Khee; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.; Alyamani, Ahmed Y.; Eldesouki, Munir M.; Ooi, Boon S.

2017-01-01

A 404-nm emitting InGaN-based laser diode with integrated-waveguide-modulator showing a large extinction ratio of 11.3 dB was demonstrated on semipolar (2021) plane GaN substrate. The device shows a low modulation voltage of −2.5 V and ∼ GHz −3 dB bandwidth, enabling 1.7 Gbps data transmission.

A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

Directory of Open Access Journals (Sweden)

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.

A 0.8–8 GHz Multi-Section Coupled Line Balun

Directory of Open Access Journals (Sweden)

Srikanth Itapu

2015-04-01

Full Text Available In this work, we propose a wideband multi-section transforming coupled-line balun using near equal length transmission line elements. The resulting design is realized by cascading several coupled-lines with minimal discontinuities. The multi-section Chebyshev matching optimizes bandwidth at the expense of passband ripple. The proposed design delivers good impedance matching and consistent 180° phase shift over 0.8–8 GHz frequency spectrum. Furthermore, the need for vias in conventional balun designs is relaxed by replacing the short-circuited (SC terminal by its equivalent dual open-circuited (OC element. The proposed design is simulated, fabricated, and measured. Both simulated and measured results are in a good agreement, and show an input port matching of below −9.7 dB over the design bandwidth, with a maximum phase and amplitude imbalance of 2.1° and 0.9 dB, respectively.

60 GHz gyrotron development program. Final report, April 1979-June 1984

International Nuclear Information System (INIS)

Shively, J.F.; Bier, R.E.; Caplan, M.

1986-01-01

The original objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW CW power output at 110 GHz. The use of cyclotron resonance interaction was pursued, and the design phases of this effort are discussed. Later, however, the program's objective was changed to develop a family of oscillators capable of producing 200 kw of peak output power at 60 GHz. Gyrotron behavior studies were performed at 28 GHz to obtain generic design information as quickly as possible. The first experimental device at 60 GHz produced over 200 kw of peak power at a pulse duration of 20 μs. Heating problems and mode interference were encountered. The second experimental tube incorporated an optimized gun location but also suffered from mode interference. The third experimental tube included modifications that reduced mode interference. It demonstrated 200 kw of peak output at 100 ms pulse duration. The fourth experimental tube, which used an older rf circuit design but in a CW configuration, produced 71.5 kW CW. The fifth experimental tube incorporated a thinner double-disc output window which improved window bandwidth and reduced window loss. This tube also incorporated modifications to the drift tunnel and cavity coupling, which had proven successful in the third experimental pulse tube tests. It produced 123 kW of CW output power at 60 GHz rf load coolant boiling and tube window failure terminated the tests. A new waterload was designed and constructed, and alternative window designs were explored

Robust Sub-harmonic Mixer at 340 GHz Using Intrinsic Resonances of Hammer-Head Filter and Improved Diode Model

Science.gov (United States)

Wang, Cheng; He, Yue; Lu, Bin; Jiang, Jun; Miao, Li; Deng, Xian-Jin; Xiong, Yong-zhong; Zhang, Jian

2017-11-01

This paper presents a sub-harmonic mixer at 340 GHz based on anti-parallel Schottky diodes (SBDs). Intrinsic resonances in low-pass hammer-head filter have been adopted to enhance the isolation for different harmonic components, while greatly minimizing the transmission loss. The application of new DC grounding structure, impedance matching structure, and suspended micro-strip mitigates the negative influences of fabrication errors from metal cavity, quartz substrate, and micro-assembly. An improved lumped element equivalent circuit model of SBDs guarantees the accuracy of simulation, which takes current-voltage (I/V) behavior, capacitance-voltage (C/V) behavior, carrier velocity saturation, DC series resistor, plasma resonance, skin effect, and four kinds of noise generation mechanisms into consideration thoroughly. The measurement indicates that with local oscillating signal of 2 mW, the lowest double sideband conversion loss is 5.5 dB at 339 GHz; the corresponding DSB noise temperature is 757 K. The 3 dB bandwidth of conversion loss is 50 GHz from 317 to 367 GHz.

Optimization of Quantum-Dot Molecular Beam Epitaxy for Broad Spectral Bandwidth Devices

KAUST Repository

Majid, Mohammed Abdul

2012-12-01

The optimization of the key growth parameters for broad spectral bandwidth devices based on quantum dots is reported. A combination of atomic force microscopy, photoluminescence of test samples, and optoelectronic characterization of superluminescent diodes (SLDs) is used to optimize the growth conditions to obtain high-quality devices with large spectral bandwidth, radiative efficiency (due to a reduced defective-dot density), and thus output power. The defective-dot density is highlighted as being responsible for the degradation of device performance. An SLD device with 160 nm of bandwidth centered at 1230 nm is demonstrated.

Optimization of Quantum-Dot Molecular Beam Epitaxy for Broad Spectral Bandwidth Devices

KAUST Repository

Majid, Mohammed Abdul; Hugues, M.; Vézian, S.; Childs, D. T. D.; Hogg, R. A.

2012-01-01

The optimization of the key growth parameters for broad spectral bandwidth devices based on quantum dots is reported. A combination of atomic force microscopy, photoluminescence of test samples, and optoelectronic characterization of superluminescent diodes (SLDs) is used to optimize the growth conditions to obtain high-quality devices with large spectral bandwidth, radiative efficiency (due to a reduced defective-dot density), and thus output power. The defective-dot density is highlighted as being responsible for the degradation of device performance. An SLD device with 160 nm of bandwidth centered at 1230 nm is demonstrated.

Fading Evaluation in the 60 GHz Band in Line-of-Sight Conditions

Directory of Open Access Journals (Sweden)

J. Reig

2014-01-01

Full Text Available An exhaustive analysis of the small-scale fading amplitude in the 60 GHz band is addressed for line-of-sight conditions (LOS. From a measurement campaign carried out in a laboratory, we have estimated the distribution of the small-scale fading amplitude over a bandwidth of 9 GHz. From the measured data, we have estimated the parameters of the Rayleigh, Rice, Nakagami-m, Weibull, and α-μ distributions for the small-scale amplitudes. The test of Kolmogorov-Smirnov (K-S for each frequency bin is used to evaluate the performance of such statistical distributions. Moreover, the distributions of the main estimated parameters for such distributions are calculated and approximated for lognormal statistics in some cases. The matching of the above distributions to the experimental distribution has also been analyzed for the lower tail of the cumulative distribution function (CDF. These parameters offer information about the narrowband channel behavior that is useful for a better knowledge of the propagation characteristics at 60 GHz.

Harbor porpoise clicks do not have conditionally minimum time bandwidth product

DEFF Research Database (Denmark)

Beedholm, Kristian

2008-01-01

The hypothesis that odontocete clicks have minimal time frequency product given their delay and center frequency values is tested by using an in-phase averaged porpoise click compared with a pure tone weighted with the same envelope. These signals have the same delay and the same center frequency...... values but the time bandwidth product of the artificial click is only 0.76 that of the original. Therefore signals with the same parameters exist that have a lower time bandwidth product. The observation that porpoise clicks are in fact minimum phase is confirmed for porpoise clicks and this property...... is argued to be incompatible with optimal reception, if auditory filters are also minimum phase....

Development of high frequency and wide bandwidth Johnson noise thermometry

International Nuclear Information System (INIS)

Crossno, Jesse; Liu, Xiaomeng; Kim, Philip; Ohki, Thomas A.; Fong, Kin Chung

2015-01-01

We develop a high frequency, wide bandwidth radiometer operating at room temperature, which augments the traditional technique of Johnson noise thermometry for nanoscale thermal transport studies. Employing low noise amplifiers and an analog multiplier operating at 2 GHz, auto- and cross-correlated Johnson noise measurements are performed in the temperature range of 3 to 300 K, achieving a sensitivity of 5.5 mK (110 ppm) in 1 s of integration time. This setup allows us to measure the thermal conductance of a boron nitride encapsulated monolayer graphene device over a wide temperature range. Our data show a high power law (T ∼ 4) deviation from the Wiedemann-Franz law above T ∼ 100 K

Characterization of a 15 GHz integrated bulk InGaAsP passively modelocked ring laser at 1.53microm.

Science.gov (United States)

Barbarin, Yohan; Bente, Erwin A J M; Heck, Martijn J R; Oei, Y S; Nötzel, Richard; Smit, Meint K

2006-10-16

We report on an extensive characterization of a 15GHz integrated bulk InGaAsP passively modelocked ring laser at 1530 nm. The laser is modelocked for a wide range of amplifier currents and reverse bias voltages on the saturable absorber. We have measured a timing jitter of 7.1 ps (20 kHz - 80 MHz), which is low for an all-active device using bulk material and due to the ring configuration. Measured output pulses are highly chirped, a FWHM bandwidth is obtained of up to 4.5 nm. Such lasers with high bandwidth pulses and compatible with active-passive integration are of great interest for OCDMA applications.

Bandwidth efficient coding

CERN Document Server

Anderson, John B

2017-01-01

Bandwidth Efficient Coding addresses the major challenge in communication engineering today: how to communicate more bits of information in the same radio spectrum. Energy and bandwidth are needed to transmit bits, and bandwidth affects capacity the most. Methods have been developed that are ten times as energy efficient at a given bandwidth consumption as simple methods. These employ signals with very complex patterns and are called "coding" solutions. The book begins with classical theory before introducing new techniques that combine older methods of error correction coding and radio transmission in order to create narrowband methods that are as efficient in both spectrum and energy as nature allows. Other topics covered include modulation techniques such as CPM, coded QAM and pulse design.

2 GHz self-aligning tandem A/D converter for SAR

DEFF Research Database (Denmark)

Søbjærg, Sten Schmidl; Christensen, Erik Lintz

2001-01-01

digitizing, and the other is to digitize the signal before digital I/Q demodulation. In both cases the digitizing may be performed by a digital front end (DFE) with two parallel analog-to-digital-converters (ADCs) sampling at 1 GHz in phase or in anti-phase respectively, provided the analog bandwidth...... of the ADC is sufficient. In the first case each ADC has to digitize a 0-400 MHz signal, and in the second case both ADCs have to digitize a 100-900 MHz signal. In both cases the sampling time alignment is a critical parameter. The paper addresses some aspects of ADC alignment in the implementation of a DFE...

Wideband Circularly Polarized Printed Ring Slot Antenna for 5 GHz – 6 GHz

Science.gov (United States)

Nasrun Osman, Mohamed; Rahim, Mohamad Helmi A.; Jusoh, Muzammil; Sabapathy, Thennarasan; Rahim, Mohamad Kamal A.; Norlyana Azemi, Saidatul

2018-03-01

This paper presents the design of circularly polarized printed slot antenna operating at 5 – 6 GHz. The proposed antenna consists of L-shaped feedline on the top of structure and circular ring slot positioned at the ground plane underneath the substrate as a radiator. A radial and narrow slot in the ground plane provides coupling between the L-shaped feedline and circular ring slot. The circular polarization is realized by implementing the slits perturbation located diagonally to perturb the current flow on the slot structure. The antenna prototype is fabricated on FR4 substrate. The simulated and measured results are compared and analyzed to demonstrate the performance of the antenna. Good measured of simulated results are obtained at the targeted operating frequency. The simulated -10dB reflection coefficient bandwidths and axial ratio are 750 MHz and 165 MHz, respectively. The investigation on the affect of the important parameters towards the reflection coefficient and axial are also presented. The proposed antenna is highly potential to be used for wireless local area network (WLAN) and wireless power transfer (WPT).

Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

Science.gov (United States)

Guan, Xiaotong; Fu, Wenjie; Yan, Yang

2018-02-01

A design of high-order mode input coupler for 220-GHz confocal gyrotron travelling wave tube is proposed, simulated, and demonstrated by experimental tests. This input coupler is designed to excite confocal TE 06 mode from rectangle waveguide TE 10 mode over a broadband frequency range. Simulation results predict that the optimized conversion loss is about 2.72 dB with a mode purity excess of 99%. Considering of the gyrotron interaction theory, an effective bandwidth of 5 GHz is obtained, in which the beam-wave coupling efficiency is higher than half of maximum. The field pattern under low power demonstrates that TE 06 mode is successfully excited in confocal waveguide at 220 GHz. Cold test results from the vector network analyzer perform good agreements with simulation results. Both simulation and experimental results illustrate that the reflection at input port S11 is sensitive to the perpendicular separation of two mirrors. It provides an engineering possibility for estimating the assembly precision.

A Microfabricated 8-40 GHz Dual-Polarized Reflector Feed

Science.gov (United States)

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.

Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

Science.gov (United States)

Pubby, Kunal; Narang, Sukhleen Bindra; Kaur, Prabhjyot; Chawla, S. K.

2017-05-01

Hexaferrite nano-particles of stoichiometric composition {{Sr}}{({{CoZr}})_x}{{F}}{{{e}}_{12 - 2x}}{{{O}}_{19}}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure {{SrF}}{{{e}}_{12}}{{{O}}_{19}} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also

Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

Energy Technology Data Exchange (ETDEWEB)

Pubby, Kunal; Narang, Sukhleen Bindra [Guru Nanak Dev University, Department of Electronics Technology, Amritsar (India); Kaur, Prabhjyot; Chawla, S.K. [Guru Nanak Dev University, Department of Chemistry, Centre for Advanced Studies-I, Amritsar (India)

2017-05-15

Hexaferrite nano-particles of stoichiometric composition Sr(CoZr){sub x}Fe{sub 12-2x}O{sub 19}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure SrFe{sub 12}O{sub 19} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also have high absorption bandwidth

Lunar Reconnaissance Orbiter K-Band (26 GHz) Signal Analysis: Initial Study Results

Science.gov (United States)

Morabito, D. D.; Heckman, D.

2017-11-01

Lower frequency telemetry bands are becoming more limited in bandwidth due to increased competition between flight projects and other entities. Higher frequency bands offer significantly more bandwidth and hence the prospect of much higher data rates. Future or prospective flight projects considering higher frequency bands such as Ka-band (32 GHz) for deep-space and K-band (26 GHz) for near-Earth telemetry links are interested in past flight experience with available received data at these frequencies. Given that there is increased degradation due to the atmosphere at these higher frequencies, there is an effort to retrieve flight data of received signal strength to analyze performance under a variety of factors. Such factors include elevation angle, season, and atmospheric conditions. This article reports on the analysis findings of over 10 million observations of received signal strength of the Lunar Reconnaissance Orbiter (LRO) spacecraft collected between 2014 and 2017. We analyzed these data to characterize link performance over a wide range of weather conditions, season, and as a function of elevation angle. Based on this analysis, we have confirmed the safety of using a 3-dB margin for preflight planning purposes. These results suggest that a 3-dB margin with respect to adverse conditions will ensure a 98 to 99 percent data return under 95 percent weather conditions at 26 GHz (K-band), thus confirming expectations from link budget predictions. The results suggest that this margin should be applicable for all elevation angles above 10 deg. Thus, missions that have sufficient power for their desired data rates may opt to use 10 deg as their minimum elevation angle. Limitations of this study include climate variability and the fact that the observations require removal of hotbody noise in order to perform an adequate cumulative distribution function (CDF) analysis, which is planned for a future comprehensive study. Flight projects may use other link margins

High-throughput and low-latency 60GHz small-cell network architectures over radio-over-fiber technologies

Science.gov (United States)

Pleros, N.; Kalfas, G.; Mitsolidou, C.; Vagionas, C.; Tsiokos, D.; Miliou, A.

2017-01-01

Future broadband access networks in the 5G framework will need to be bilateral, exploiting both optical and wireless technologies. This paper deals with new approaches and synergies on radio-over-fiber (RoF) technologies and how those can be leveraged to seamlessly converge wireless technology for agility and mobility with passive optical networks (PON)-based backhauling. The proposed convergence paradigm is based upon a holistic network architecture mixing mm-wave wireless access with photonic integration, dynamic capacity allocation and network coding schemes to enable high bandwidth and low-latency fixed and 60GHz wireless personal area communications for gigabit rate per user, proposing and deploying on top a Medium-Transparent MAC (MT-MAC) protocol as a low-latency bandwidth allocation mechanism. We have evaluated alternative network topologies between the central office (CO) and the access point module (APM) for data rates up to 2.5 Gb/s and SC frequencies up to 60 GHz. Optical network coding is demonstrated for SCM-based signaling to enhance bandwidth utilization and facilitate optical-wireless convergence in 5G applications, reporting medium-transparent network coding directly at the physical layer between end-users communicating over a RoF infrastructure. Towards equipping the physical layer with the appropriate agility to support MT-MAC protocols, a monolithic InP-based Remote Antenna Unit optoelectronic PIC interface is shown that ensures control over the optical resource allocation assisting at the same time broadband wireless service. Finally, the MT-MAC protocol is analysed and simulation and analytical theoretical results are presented that are found to be in good agreement confirming latency values lower than 1msec for small- to mid-load conditions.

Making Better Use of Bandwidth: Data Compression and Network Management Technologies

National Research Council Canada - National Science Library

Pane, John F; Joe, Leland

2005-01-01

.... Furthermore, future demands seem likely to increase. Researchers from RAND Arroyo Center have been seeking ways in which the Army might use bandwidth better, specifically how new compression technologies might help improve information throughput...

45-110 GHz Quad-Ridge Horn With Stable Gain and Symmetric Beam

Science.gov (United States)

Manafi, Sara; Al-Tarifi, Muhannad; Filipovic, Dejan S.

2017-09-01

A quad-ridge horn antenna with stabilized gain and minimum difference between Eand H-plane half-power beamwidths (HPBWs) is demonstrated for operation over 45-110 GHz bandwidth. Multistep flaring and corrugations on a finite ground plane are applied to obtain stable radiation patterns with 16-dBi minimum gain over the entire range. The computational studies are validated through measurements of a 3-D printed prototype using the direct metal laser sintering (DMLS) process. Accurate fabrication with achieved surface roughness of DMLS is a viable fabrication process for wideband horn antennas at millimeter-wave frequencies.

Compact 84 GHz passive mode-locked fiber laser using dual-fiber coupled fused-quartz microresonator

Science.gov (United States)

Liu, Tze-An; Hsu, Yung; Chow, Chi-Wai; Chuang, Yi-Chen; Ting, Wei-Jo; Wang, Bo-Chun; Peng, Jin-Long; Chen, Guan-Hong; Chang, Yuan-Chia

2017-10-01

We propose and demonstrate a compact and portable-size 84-GHz passive mode-locked fiber laser, in which a dual-fiber coupled fused-quartz microresonator is employed as the intracavity optical comb filter as well as the optical nonlinear material for optical frequency comb generation. About eight coherent optical tones can be generated in the proposed fiber laser. The 20-dB bandwidth is larger than 588 GHz. The full-width half-maximum pulse-width of the proposed laser is 2.5 ps. We also demonstrate the feasibility of using the proposed passive mode-locked fiber laser to carry a 5-Gbit/s on-off-keying signal and transmit over 20-km standard single mode fiber. A 7% forward error correction requirement can be achieved, showing the proposed fiber laser can be a potential candidate for fiber-wireless applications.

Network Bandwidth Utilization Forecast Model on High Bandwidth Network

Energy Technology Data Exchange (ETDEWEB)

Yoo, Wucherl; Sim, Alex

2014-07-07

With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2percent. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

Network bandwidth utilization forecast model on high bandwidth networks

Energy Technology Data Exchange (ETDEWEB)

Yoo, Wuchert (William) [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-03-30

With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2%. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

Wide-bandwidth electron bolometric mixers - A 2DEG prototype and potential for low-noise THz receivers

Science.gov (United States)

Yang, Jian-Xun; Agahi, Farid; Dai, Dong; Musante, Charles F.; Grammer, Wes; Lau, Kei M.; Yngvesson, K. S.

1993-01-01

This paper presents a new type of electron bolometric ('hot electron') mixer. We have demonstrated a 3 order-of-magnitude improvement in the bandwidth compared with previously known types of electron bolometric mixers, by using the two-dimensional electron gas (2DEG) medium at the heterointerface between AlGaAs and GaAs. We have tested both in-house MOCVD-grown material and MBE material, with similar results. The conversion loss (Lc) at 94 GHz is presently 18 dB for a mixer operating at 20 K, and calculations indicate that Lc can be decreased to about 10 dB in future devices. Calculated and measured curves of Lc versus P(LO), and I(DC), respectively, agree well. We argue that there are several different configurations of electron bolometric mixers, which will all show wide bandwidth, and that these devices are likely to become important as low-noise THz receivers in the future.

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

Directory of Open Access Journals (Sweden)

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.

Comparison of OQPSK and CPM for Communications at 60 GHz with a Nonideal Front End

Directory of Open Access Journals (Sweden)

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.

Comparison of OQPSK and CPM for Communications at 60 GHz with a Nonideal Front End

Directory of Open Access Journals (Sweden)

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.

RF MEMS suspended band-stop resonator and filter for frequency and bandwidth continuous fine tuning

International Nuclear Information System (INIS)

Jang, Yun-Ho; Kim, Yong-Kweon; Llamas-Garro, Ignacio; Kim, Jung-Mu

2012-01-01

We firstly propose the concept of a frequency and bandwidth fine-tuning method using an RF MEMS-based suspended tunable band-stop resonator. We experimentally show the feasibility of the continuously tuned resonator, including a second-order filter, which consists of cascaded resonators to achieve center frequency and bandwidth fine tuning. The structure consists of a freestanding half-wavelength (λ/2) resonator connected to a large displacement comb actuator. The lateral movement of the λ/2 resonator over the main transmission line produces different electromagnetic decoupling values from the main transmission line. The decoupled energy leads to continuous center frequency and bandwidth tuning using the band-stop resonator circuit for fine-tuning applications. The freestanding λ/2 resonator plays the role of a variable capacitor as well as a decoupling resonator in the proposed structure. The fabricated tunable filter shows suitability for Ku-band wireless communication system applications with continuous reconfiguration

A Wideband High-Gain Dual-Polarized Slot Array Patch Antenna for WiMAX Applications in 5.8 GHz

Directory of Open Access Journals (Sweden)

Amir Reza Dastkhosh

2012-01-01

Full Text Available A low-cost, easy-to-fabricate, wideband and high-gain dual-polarized array antenna employing an innovative microstrip slot patch antenna element is designed and fabricated. The design parameters of the antenna are optimized using commercial softwares (Microwave Office and Zeland IE3D to get the suitable -parameters and radiation patterns. Finally, the simulation results are compared to the experimental ones and a good agreement is demonstrated. The antenna has an approximately bandwidth of 14% (5.15–5.9 GHz which covers Worldwide Interoperability Microwave Access (WiMAX/5.8. It also has the peak gain of 26 dBi for both polarizations and high isolation between two ports over a wide bandwidth.

A U-Shaped Slot UWB Antenna with Flexible and Wide Tunable Dual Notch Band

Directory of Open Access Journals (Sweden)

Zhang Zhongmin

2016-01-01

Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with flexible and wide tunable dual bandnotched characteristics is proposed in this paper. The dual band-notched function is achieved by using an U-shaped slot inserted into the ellipse radiation patch and by using an elliptic parasitic slit placed near the ground plane. The wide tunable band-notched characteristic is implemented by adjusting the length of U-shaped slot and by adjusting the length of ellipse parasitic slit. The design aims to achieve wide reconfigurable band-notched features on the UWB antenna. The simulated results indicate that the proposed antenna has a wide bandwidth (VSWR under 2 from 2.9GHz to 12.6GHz with fractional bandwidth of 125%, and has a wide tunable notch band center frequency from 4.5GHz to 12.4GHz.

Integration of a versatile bridge concept in a 34 GHz pulsed/CW EPR spectrometer

Science.gov (United States)

Band, Alan; Donohue, Matthew P.; Epel, Boris; Madhu, Shraeya; Szalai, Veronika A.

2018-03-01

We present a 34 GHz continuous wave (CW)/pulsed electron paramagnetic resonance (EPR) spectrometer capable of pulse-shaping that is based on a versatile microwave bridge design. The bridge radio frequency (RF)-in/RF-out design (500 MHz to 1 GHz input/output passband, 500 MHz instantaneous input/output bandwidth) creates a flexible platform with which to compare a variety of excitation and detection methods utilizing commercially available equipment external to the bridge. We use three sources of RF input to implement typical functions associated with CW and pulse EPR spectroscopic measurements. The bridge output is processed via high speed digitizer and an in-phase/quadrature (I/Q) demodulator for pulsed work or sent to a wideband, high dynamic range log detector for CW. Combining this bridge with additional commercial hardware and new acquisition and control electronics, we have designed and constructed an adaptable EPR spectrometer that builds upon previous work in the literature and is functionally comparable to other available systems.

Entanglement swapping of a GHZ state via a GHZ-like state

Energy Technology Data Exchange (ETDEWEB)

Tsai, Chia-Wei; Hwang, Tzonelih, E-mail: hwangtl@ismail.csie.ncku.edu.t [National Cheng Kung University, Department of Computer Science and Information Engineering, No. 1 Ta-Hsueh Road, Tainan City 701, Taiwan (China)

2011-10-15

This study uses the Greenberger-Horne-Zeilinger (GHZ)-like state |G>= 1/2 (|001>+|010>+|100>+|111>) to establish an entanglement swapping protocol on a pure GHZ state. A quantum circuit is proposed to assist in teleporting the entanglement of the pure GHZ state. Furthermore, on the basis of the generation of the GHZ-like state, an improved protocol to reduce the number of transmitted photons required in the process of entanglement swapping is proposed.

A 130 GHz Electro-Optic Ring Modulator with Double-Layer Graphene

Directory of Open Access Journals (Sweden)

Lei Wu

2017-02-01

Full Text Available The optical absorption coefficient of graphene will change after injecting carriers. Based on this principle, a high-speed double-layer graphene electro-optic modulator with a ring resonator structure was designed in this paper. From the numerical simulations, we designed a modulator. Its optical bandwidth is larger than 130 GHz, the switching energy is 0.358 fJ per bit, and the driven voltage is less than 1.2 V. At the same time, the footprint of the proposed modulator is less than 10 microns squared, which makes the process compatible with the Complementary Metal Oxide Semiconductors (CMOS process. This will provide the possibility for the on-chip integration of the photoelectric device.

Simultaneous generation of 40, 80 and 120 GHz optical millimeter-wave from one Mach-Zehnder modulator and demonstration of millimeter-wave transmission and down-conversion

Science.gov (United States)

Zhou, Wen; Qin, Chaoyi

2017-09-01

We demonstrate multi-frequency QPSK millimeter-wave (mm-wave) vector signal generation enabled by MZM-based optical carrier suppression (OCS) modulation and in-phase/quadrature (I/Q) modulation. We numerically simulate the generation of 40-, 80- and 120-GHz vector signal. Here, the three different signals carry the same QPSK modulation information. We also experimentally realize 11Gbaud/s QPSK vector signal transmission over 20 km fiber, and the generation of the vector signals at 40-GHz, 80-GHz and 120-GHz. The experimental results show that the bit-error-rate (BER) for all the three different signals can reach the forward-error-correction (FEC) threshold of 3.8×10-3. The advantage of the proposed system is that provide high-speed, high-bandwidth and high-capacity seamless access of TDM and wireless network. These features indicate the important application prospect in wireless access networks for WiMax, Wi-Fi and 5G/LTE.

HTS dual-band bandpass filters using stub-loaded hair-pin resonators for mobile communication systems

Energy Technology Data Exchange (ETDEWEB)

Sekiya, N., E-mail: nsekiya@yamanashi.ac.jp; Sugiyama, S.

2014-09-15

Highlights: • We have developed a HTS five-pole dual-band bandpass filter using stub-loaded hair-pin resonators. • The proposed dual-band BPF can independently control of the center frequency. • Flexibly adjustment of the bandwidth can be achieved by the H-shaped waveguide. • The proposed BPF is evaluated by simulation and measurement with good agreement. - Abstract: A HTS dual-band bandpass filter is developed to obtain sharp-cut off characteristics for mobile communication systems. The filter is composed of five stub-loaded hair-pin resonators with H-shaped waveguides between them. The main advantage of the proposed filter is to allow independent control of the center frequency of the first and second bands. The bandwidths can be flexibly adjusted using the H-shaped waveguide. An electromagnetic simulator was used to design and analyze the filter, which have a 3.5-GHz center frequency and a 70-MHz (2%) bandwidth for the first band and a 5.0-GHz center frequency and a 100-MHz (2%) bandwidth for the second band. The filter was fabricated using YBa{sub 2}Cu{sub 3}O{sub y} thin film on an Al{sub 2}O{sub 3} substrate. Ground plane was fabricated using Au thin film. The measured frequency responses of the filter tally well with the simulated ones.

Bandwidth broadening effect in a traveling-wave-tube amplifier by using impulse electron beam

International Nuclear Information System (INIS)

Jung, Sang Wook; Choi, Jin Joo; Kim, Seon Joo

2012-01-01

This paper reports on a wideband amplification mechanism involving an impulse electron beam. To prove broadband amplification with the impulse beam, we perform 3-dimensional particle-in-cell (3D PIC) code simulation. An impulse electron beam with a pulse width of 1 ns with electric potential 17.2 kV is injected into an interaction circuit of a coupled-cavity traveling-wave-tube (CCTWT) driven by a continuous-wave (CW) signal of 29.1 GHz. The resulting output bandwidth was 2.96%, and the peak output power of 713 W was the same as that obtained with CW operation at a single frequency. The simulation yielded very similar results with ultra short impulse signal from the simulation.

Development of a thermionic magnicon amplifier at 11.4 GHz. Final report for period May 16, 1995 - May 15, 2001

International Nuclear Information System (INIS)

Gold, Steven H.; Fliflet, Arne W.

2001-01-01

This is the final report on the research program ''Development of a Thermionic Magnicon Amplifier at 11.4 GHz,'' which was carried out by the Plasma Physics Division of the Naval Research Laboratory. Its goal was to develop a high-power, frequency-doubling X-band magnicon amplifier, an advanced scanning-beam amplifier, for use in future linear colliders. The final design parameters were 61 MW at 11.424 GHz, 59 dB gain, 59% efficiency, 1 microsecond pulselength and 10 Hz repetition rate. At the conclusion of this program, the magnicon was undergoing high-power conditioning, having already demonstrated high-power operation, phase stability, a linear drive curve, a small operational frequency bandwidth and a spectrally pure, single-mode output

Bandwidth-Enhanced Low-Profile Antenna with Parasitic Patches

Directory of Open Access Journals (Sweden)

Son Xuat Ta

2017-01-01

Full Text Available This paper presents low-profile broadband antennas, which are composed of four parasitic patches placed between planar radiators and a perfect electric conductor ground plane. Two types of planar radiators, a conventional dipole and a crossed dipole, are employed to produce linearly polarized (LP and circularly polarized (CP radiations, respectively. The radiator and parasitic patches are realized on thin substrates to lower the cost. Owing to the presence of parasitic patches, the antenna performance improves in terms of profile reduction, resonant frequency decrease, and bandwidth enhancement. These improvements are discussed and confirmed computationally and experimentally. The LP design with the overall dimensions of 120 mm × 120 mm × 16.3 mm (0.64λ0 × 0.64λ0 × 0.087λ0 at 1.6 GHz has a |S11|  96%. The CP design, which has the same physical size as the LP case, has a |S11|  90%.

Recent operating experience with Varian 70 GHz and 140 GHz gyrotrons

International Nuclear Information System (INIS)

Felch, K.; Bier, R.; Fox, L.; Huey, H.; Ives, L.; Jory, H.; Lopez, N.; Shively, J.; Spang, S.

1985-01-01

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 TE 031 0 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

Trade-off between bandwidth and efficiency in semipolar (20 2 ¯ 1 ¯) InGaN/GaN single- and multiple-quantum-well light-emitting diodes

Science.gov (United States)

Monavarian, M.; Rashidi, A.; Aragon, A. A.; Nami, M.; Oh, S. H.; DenBaars, S. P.; Feezell, D.

2018-05-01

InGaN/GaN light-emitting diodes (LEDs) with large modulation bandwidths are desirable for visible-light communication. Along with modulation speed, the consideration of the internal quantum efficiency (IQE) under operating conditions is also important. Here, we report the modulation characteristics of semipolar (20 2 ¯ 1 ¯ ) InGaN/GaN (LEDs) with single-quantum well (SQW) and multiple-quantum-well (MQW) active regions grown on free-standing semipolar GaN substrates with peak internal quantum efficiencies (IQEs) of 0.93 and 0.73, respectively. The MQW LEDs exhibit on average about 40-80% higher modulation bandwidth, reaching 1.5 GHz at 13 kA/cm2, but about 27% lower peak IQE than the SQW LEDs. We extract the differential carrier lifetimes (DLTs), RC parasitics, and carrier escape lifetimes and discuss their role in the bandwidth and IQE characteristics. A coulomb-enhanced capture process is shown to rapidly reduce the DLT of the MQW LED at high current densities. Auger recombination is also shown to play little role in increasing the speed of the LEDs. Finally, we investigate the trade-offs between the bandwidth and efficiency and introduce the bandwidth-IQE product as a potential figure of merit for optimizing speed and efficiency in InGaN/GaN LEDs.

Design of a magnetron injection gun for a 17.5-GHz

International Nuclear Information System (INIS)

Ha, H. J.; Kim, J. E.; Park, G. S.

1996-01-01

A gyrotwystron which is composed of cavities (gyro-klystron) and waveguides (gyro-TWT) is under investigation for broader bandwidth with high efficiency. A magnetron injection gun (MIG) for the gyrotwystron is designed with the trade-off equation for the MIG and optimized by computer simulation using the e-gun code. A 300-kW, 60-kV MIG with α ≡ υ t /υ z = 1.2 and Δυ z ≤ 5% designed for a 17.5-GHz gyrotwystron is discussed in this paper. Also, the effect of various MIG parameters, such as the beam voltage, the beam current, the magnetic field, the cathode radius and angle, and the MIG dimensions, on the characteristics of the beam (α, Δυ z ) is studied. (author)

60 GHz system-on-chip (SoC) with built-in memory and an on-chip antenna

KAUST Repository

Ghaffar, Farhan A.

2014-04-01

A novel 60 GHz transmitter SoC with an on-chip antenna and integrated memory in CMOS 65 nm technology is presented in this paper. This highly integrated transmitter design can support a data rate of 2 GBPS with a transmission range of 1 m. The transmitter consists of a fundamental frequency 60 GHz PLL which covers the complete ISM band. The modulator following the PLL can support both BPSK and OOK modulation schemes. Both stored data on the integrated memory or directly from an external source can be transmitted. A tapered slot on chip antenna is integrated with the power amplifier to complete the front end of the transmitter design. Size of the complete transmitter with on-chip antenna is only 1.96 mm × 1.96 mm. The core circuits consume less than 100 mW of power. The high data rate capability of the design makes it extremely suitable for bandwidth hungry applications such as unencrypted HD video streaming and transmission.

60 GHz system-on-chip (SoC) with built-in memory and an on-chip antenna

KAUST Repository

Ghaffar, Farhan A.; Arsalan, Muhammad; Cheema, Hammad; Salama, Khaled N.; Shamim, Atif

2014-01-01

A novel 60 GHz transmitter SoC with an on-chip antenna and integrated memory in CMOS 65 nm technology is presented in this paper. This highly integrated transmitter design can support a data rate of 2 GBPS with a transmission range of 1 m. The transmitter consists of a fundamental frequency 60 GHz PLL which covers the complete ISM band. The modulator following the PLL can support both BPSK and OOK modulation schemes. Both stored data on the integrated memory or directly from an external source can be transmitted. A tapered slot on chip antenna is integrated with the power amplifier to complete the front end of the transmitter design. Size of the complete transmitter with on-chip antenna is only 1.96 mm × 1.96 mm. The core circuits consume less than 100 mW of power. The high data rate capability of the design makes it extremely suitable for bandwidth hungry applications such as unencrypted HD video streaming and transmission.

Developing Reliable Telemedicine Platforms with Unreliable and Limited Communication Bandwidth

Science.gov (United States)

2017-10-01

AFRL-SA-WP-TR-2017-0019 Developing Reliable Telemedicine Platforms with Unreliable and Limited Communication Bandwidth Peter F...Wright-Patterson AFB, OH 45433-7913 DISTRIBUTION STATEMENT A. Approved for public release. Distribution is unlimited. STINFO COPY NOTICE AND...invention that may relate to them. Qualified requestors may obtain copies of this report from the Defense Technical Information Center (DTIC) (http

A 2.4-GHz ISM RF and UWB hybrid RFID real-time locating system for industrial enterprise Internet of Things

Science.gov (United States)

Zhai, Chuanying; Zou, Zhuo; Zhou, Qin; Mao, Jia; Chen, Qiang; Tenhunen, Hannu; Zheng, Lirong; Xu, Lida

2017-07-01

This paper presents a 2.4-GHz radio frequency (RF) and ultra-wide bandwidth (UWB) hybrid real-time locating system (RTLS) for industrial enterprise Internet of Things (IoT). It employs asymmetric wireless link, that is, UWB radio is utilised for accurate positioning up to 10 cm in critical sites, whereas 2.4-GHz RF is used for tag control and coarse positioning in non-critical sites. The specified communication protocol and the adaptive tag synchronisation rate ensure reliable and deterministic access with a scalable system capacity and avoid unpredictable latency and additional energy consumption of retransmissions due to collisions. The tag, consisting of a commercial 2.4-GHz transceiver and a customised application-specific integrated circuit (ASIC) UWB transmitter (Tx), is able to achieve up to 3 years' battery life at 1600 tags per position update second with 1000 mAh battery in one cluster. The time difference of arrival (TDoA)-based positioning experiment at UWB radio is performed on the designed software-defined radio (SDR) platform.

A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

Science.gov (United States)

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.

MOBILE MAPPING BY FMCW SYNTHETIC APERTURE RADAR OPERATING AT 300 GHZ

Directory of Open Access Journals (Sweden)

S. Palm

2016-06-01

Full Text Available While optical cameras or laser systems are widely used for mobile mapping low attention was payed for radar systems. Due to new semiconductor technologies, compact and leight weight SAR systems based on the Frequency Modulated Continuous Wave (FMCW principle in the millimeter wave domain can serve for mobile radar mapping on cars. For mapping of long stripes along roads in close range a special strategy for focusing of SAR images was developed. Hereby local adapted planes for processing are used considering the IMU data of the sensor. An experimental system was designed for high resolution radar mapping of urban scenes in close range geometry. This small and leight weighted system has a bandwidth of 30 GHz (5 mm resolution and operates with 300 GHz in the lower terahertz domain. Experiments with a van in an urban scenario were carried out for proof of applicability of an operating SAR system resolving objects in the subcentimeter domain. The results show that narrow cracks in the asphalt of the road are visible and the measuring of small metallic objects placed in the scene is possible. Based on this mobile mapping techniques a first result from an acquisition of vertical facade structure is shown.

Improved-Bandwidth Transimpedance Amplifier

Science.gov (United States)

Chapsky, Jacob

2009-01-01

The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

Broadband planar antenna with improved pattern bandwidth

Directory of Open Access Journals (Sweden)

Carlos Suárez

2012-01-01

Full Text Available En este articulo se presenta el diseño de una antena plana F invertida que utiliza una geometria en la cual se dividen en dos partes las placas superior (radiante, de corto, de tierra y de excitación capacitiva. Mediante esta geometria y la técnica de excitación capacitiva se logra alcanzar anchos de banda de diagrama y de impedancia cercanos al 52.44% (1.66 GHz a 2.84 GHz Ydel 8% (3.36 GHz a 3.64 GHz para un VSWR <: 2.0. Los resultados medidos para estos parámetros son superiores a los obtenidos mediante la técnica tradicional de excitación directa con terminal u otros métodos de excitación capacitiva utilizado en antenas planas F invertidas (PIFA. El prototipo construido permite la operación simultanea de la antena en las bandas de Des 1800, Des 1900, UMTS, WiFi, 2.4GHz, WiMAX (2.3GHz a 2.5GHz y (3.4GHz a 3.5GHz y en la banda asignada para el estándar (Bluetootb. Los diagramas de radiación obtenidos dentro de estos anchos de banda son razonablemente omnidireccionales.

Novel micromachined on-chip 10-elements wire-grid array operating at 60 GHz

KAUST Repository

Sallam, Mai O.

2017-06-07

This paper presents a new topology for a wire-grid antenna array which operates at 60 GHz. The array consists of ten λ/2 dipole radiators connected via non-radiating connectors. Both radiators and connectors are placed on top of narrow silicon walls. The antenna is fed with a coplanar microstrip lines placed at the other side of the wafer and is connected with its feeding transmission lines using through-silicon-vias. The antenna is optimized for two cases: using high- and low-resistivity silicon substrates. The former has better radiation characteristics while the later is more compatible with the driving electronic circuits. The antenna has high directivity, reasonable bandwidth and high polarization purity.

A 75 GHz silicon metal-semiconductor-metal Schottky photodiode

International Nuclear Information System (INIS)

Alexandrou, S.; Wang, C.; Hsiang, T.Y.; Liu, M.Y.; Chou, S.Y.

1993-01-01

The ultrafast characteristics of crystalline-silicon metal-semiconductor-metal (MSM) photodiodes with 300 nm finger width and spacing were measured with a subpicosecond electro-optic sampling system. Electrical responses with full width at half maximum as short as 5.5 and 11 ps, at corresponding 3 dB bandwidths of 75 and 38 GHz, were generated by violet and red photons, respectively. The difference is attributed to the photon penetration depth which is much larger than the diode finger spacing at red, but smaller at violet. Light-intensity dependence was also examined at different wavelengths, indicating a linear relation and a higher sensitivity in the violet. These results not only demonstrated the fastest silicon photodetector reported to date, but also pinpointed the dominant speed-limiting factor of silicon MSM photodiodes. A configuration is suggested to improve the speed of these detectors at long wavelengths

Design and development of a multifunction millimeter wave sensor

Science.gov (United States)

Nadimi, Sayyid Abdolmajid

1998-11-01

The millimeter-wave (MMW) spectrum (30-300 GHz) offers a unique combination of features that are advantageous when retrieving information about the environment. Due to small wavelengths involved, physically small antennas may be used to obtain very high gains (>50 dB) and resulting high spatial resolutions. Moreover, some features have scattering and emission behaviors that are more sensitive at MMW wavelengths than at microwave wavelengths. Examples include, water vapor (H2O). fog, haze, clouds, ozone (O 3) molecules, and chlorine monoxide (ClO) have rotational spectra in this region. The 75-110 GHz (W-band) atmospheric window is relatively quiet, and it can supply spectral information that can be useful in identifying and quantifying pollutants. Information such as the size and concentration of particulate pollutants can be obtained using radar techniques at W-band. Although there have been some activities at millimeter wave frequencies over very narrow bandwidths, there is a great need for wider bandwidth instruments for studying scattering and emission behaviors. To address this need and provide a versatile system for laboratory studies of electromagnetic phenomena at millimeter-wave frequencies, a multifunctionmillimeter- wave sensor has been designed and developed. This instrument is an active/passive wide band sensor operating in the 75-110 GHz region of the millimeter wave spectrum in four primary modes: (1)As a spectrometer measuring absorption over the entire 75-110 GHz region. (2)As a radiometer measuring blackbody emissions over the entire 75-110 GHz region. (3)As a pulse radar over a 500 MHz bandwidth centered around 93.1 GHz with a peak power of 200 mW. (4)As a step frequency radar when used in combination with a network analyzer over selected 9 GHz bandwidth segments (75-84, 84-93, 93-102, and 102-110) of the 75-110 GHz region. Measurements were performed on two volume fraction (15% and 20%) dense random media targets using this system. The results

A 3 GHz transimpedance OEIC receiver for 1.3-1.55 μm fiber-optic systems

International Nuclear Information System (INIS)

Chang, G.K.; Hong, W.P.; Gimlett, J.L.; Bhat, R.; Nguyen, C.K.; Sasaki, G.; Young, J.C.

1990-01-01

This paper reports a high-performance, MSM-HEMT transimpedance photoreceiver fabricated using OMCVD grown InAlAs/InGaAs heterostructures on an InP substrate. This is the first demonstration of a monolithically integrated receiver amplifier that incorporates a cascode amplifier stage and a Schottky diode level-shifting stage implemented on InP-based OEIC photoreceivers. The transimpedance amplifier has an open loop gain of 5.7 and a bandwidth of 3.0 GHz which represent the highest gain and the highest speed performance reported for 1.3--1.55 μm wavelength OEIC receivers

Bandwidth-on-demand motion control

NARCIS (Netherlands)

Van Loon, S.J.L.M.; Hunnekens, B.G.B.; Simon, A.S.; van de Wouw, N.; Heemels, W.P.M.H.

2018-01-01

In this brief, we introduce a 'bandwidth-on-demand' variable-gain control (VGC) strategy that allows for a varying bandwidth of the feedback controller. The proposed VGC can achieve improved performance given time-varying, reference-dependent performance requirements compared with linear

A 311-GHz Fundamental Oscillator Using InP HBT Technology

Science.gov (United States)

Gaier, Todd; Fung, King Man; Samoska, Lorene; Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, W.R.

2010-01-01

amount of feedback than the common-emitter design, therefore preserving device gain, and was chosen for the oscillator design. The submillimeter-wave region offers several advantages for sensors and communication systems, such as high resolution and all-weather imaging due to the short-wavelength, and improved communication speeds by access to greater frequency bandwidth. This oscillator circuit is a prototype of the first HBT oscillator operating above 300 GHz. Additional development is necessary to increase the output power of the circuit for radar and imaging applications.

Design of Two Novel Dual Band-Notched UWB Antennas

Directory of Open Access Journals (Sweden)

Bing Li

2012-01-01

Full Text Available Two novel dual band-notched ultra-wideband (UWB printed monopole antennas with simple structure and small size are presented. The size of both antennas is 25×25×0.8 mm3. The bandwidth of one of the proposed antenna can be from 2.7 GHz to 36.8 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 5.14–5.94 GHz for WLAN applications. The bandwidth of the other is ranging for 2.7 to 41.1 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 4.8–5.9 GHz for WLAN applications. Bandwidths of the antennas are about 512% and 455% wider than those of conventional band-notched UWB antennas, respectively. In addition, the time-domain characteristics of the two antennas are investigated to show the difference between both antennas.

Integration of a versatile bridge concept in a 34 GHz pulsed/CW EPR spectrometer.

Science.gov (United States)

Band, Alan; Donohue, Matthew P; Epel, Boris; Madhu, Shraeya; Szalai, Veronika A

2018-03-01

We present a 34 GHz continuous wave (CW)/pulsed electron paramagnetic resonance (EPR) spectrometer capable of pulse-shaping that is based on a versatile microwave bridge design. The bridge radio frequency (RF)-in/RF-out design (500 MHz to 1 GHz input/output passband, 500 MHz instantaneous input/output bandwidth) creates a flexible platform with which to compare a variety of excitation and detection methods utilizing commercially available equipment external to the bridge. We use three sources of RF input to implement typical functions associated with CW and pulse EPR spectroscopic measurements. The bridge output is processed via high speed digitizer and an in-phase/quadrature (I/Q) demodulator for pulsed work or sent to a wideband, high dynamic range log detector for CW. Combining this bridge with additional commercial hardware and new acquisition and control electronics, we have designed and constructed an adaptable EPR spectrometer that builds upon previous work in the literature and is functionally comparable to other available systems. Published by Elsevier Inc.

Glass Industry Bandwidth Analysis

Energy Technology Data Exchange (ETDEWEB)

Rue, David M. [Gas Technology Inst., Des Plaines, IL (United States)

2006-07-01

This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

Industrial Glass Bandwidth Analysis

Energy Technology Data Exchange (ETDEWEB)

Rue, David M. [Gas Technology Inst., Des Plaines, IL (United States); Servaites, James [Gas Technology Inst., Des Plaines, IL (United States); Wolf, Warren [Gas Technology Inst., Des Plaines, IL (United States)

2007-08-01

This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

The effects of noise-bandwidth, noise-fringe duration, and temporal signal location on the binaural masking-level difference.

Science.gov (United States)

Yasin, Ifat; Henning, G Bruce

2012-07-01

The effects of forward and backward noise fringes on binaural signal detectability were investigated. Masked thresholds for a 12-ms, 250-Hz, sinusoidal signal masked by Gaussian noise, centered at 250 Hz, with bandwidths from 3 to 201 Hz, were obtained in N(0)S(0) and N(0)S(π) configurations. The signal was (a) temporally centered in a 12-ms noise burst (no fringe), (b) presented at the start of a 600-ms noise burst (backward fringe), or (c) temporally centered in a 600-ms noise burst (forward-plus-backward fringe). For noise bandwidths between 3 and 75 Hz, detection in N(0)S(0) improved with the addition of a backward fringe, improving further with an additional forward fringe; there was little improvement in N(0)S(π). The binaural masking-level difference (BMLD) increased from 0 to 8 dB with a forward-plus-backward fringe as noise bandwidths increased to 100 Hz, increasing slightly to 10 dB at 201 Hz. This two-stage increase was less pronounced with a backward fringe. With no fringe, the BMLD was about 10-14 dB at all bandwidths. Performance appears to result from the interaction of across-time and across-frequency listening strategies and the possible effects of gain reduction and suppression, which combine in complex ways. Current binaural models are, as yet, unable to account fully for these effects.

Optimal Bandwidth Selection for Kernel Density Functionals Estimation

Directory of Open Access Journals (Sweden)

Su Chen

2015-01-01

Full Text Available The choice of bandwidth is crucial to the kernel density estimation (KDE and kernel based regression. Various bandwidth selection methods for KDE and local least square regression have been developed in the past decade. It has been known that scale and location parameters are proportional to density functionals ∫γ(xf2(xdx with appropriate choice of γ(x and furthermore equality of scale and location tests can be transformed to comparisons of the density functionals among populations. ∫γ(xf2(xdx can be estimated nonparametrically via kernel density functionals estimation (KDFE. However, the optimal bandwidth selection for KDFE of ∫γ(xf2(xdx has not been examined. We propose a method to select the optimal bandwidth for the KDFE. The idea underlying this method is to search for the optimal bandwidth by minimizing the mean square error (MSE of the KDFE. Two main practical bandwidth selection techniques for the KDFE of ∫γ(xf2(xdx are provided: Normal scale bandwidth selection (namely, “Rule of Thumb” and direct plug-in bandwidth selection. Simulation studies display that our proposed bandwidth selection methods are superior to existing density estimation bandwidth selection methods in estimating density functionals.

Potential of Sub-GHz Wireless for Future IoT Wearables and Design of Compact 915 MHz Antenna

Directory of Open Access Journals (Sweden)

Adolfo Di Serio

2017-12-01

Full Text Available Internet of Things (IoT technology is rapidly emerging in medical applications as it offers the possibility of lower-cost personalized healthcare monitoring. At the present time, the 2.45 GHz band is in widespread use for these applications but in this paper, the authors investigate the potential of the 915 MHz ISM band in implementing future, wearable IoT devices. The target sensor is a wrist-worn wireless heart rate and arterial oxygen saturation (SpO2 monitor with the goal of providing efficient wireless functionality and long battery lifetime using a commercial Sub-GHz low-power radio transceiver. A detailed analysis of current consumption for various wireless protocols is also presented and analyzed. A novel 915 MHz antenna design of compact size is reported that has good resilience to detuning by the human body. The antenna also incorporates a matching network to meet the challenging bandwidth requirements and is fabricated using standard, low-cost FR-4 material. Full-Wave EM simulations are presented for the antenna placed in both free-space and on-body cases. A prototype antenna is demonstrated and has dimensions of 44 mm × 28 mm × 1.6 mm. The measured results at 915 MHz show a 10 dB return loss bandwidth of 55 MHz, a peak realized gain of − 2.37 dBi in free-space and − 6.1 dBi on-body. The paper concludes by highlighting the potential benefits of 915 MHz operation for future IoT devices.

Potential of Sub-GHz Wireless for Future IoT Wearables and Design of Compact 915 MHz Antenna.

Science.gov (United States)

Di Serio, Adolfo; Buckley, John; Barton, John; Newberry, Robert; Rodencal, Matthew; Dunlop, Gary; O'Flynn, Brendan

2017-12-22

Internet of Things (IoT) technology is rapidly emerging in medical applications as it offers the possibility of lower-cost personalized healthcare monitoring. At the present time, the 2.45 GHz band is in widespread use for these applications but in this paper, the authors investigate the potential of the 915 MHz ISM band in implementing future, wearable IoT devices. The target sensor is a wrist-worn wireless heart rate and arterial oxygen saturation (SpO2) monitor with the goal of providing efficient wireless functionality and long battery lifetime using a commercial Sub-GHz low-power radio transceiver. A detailed analysis of current consumption for various wireless protocols is also presented and analyzed. A novel 915 MHz antenna design of compact size is reported that has good resilience to detuning by the human body. The antenna also incorporates a matching network to meet the challenging bandwidth requirements and is fabricated using standard, low-cost FR-4 material. Full-Wave EM simulations are presented for the antenna placed in both free-space and on-body cases. A prototype antenna is demonstrated and has dimensions of 44 mm × 28 mm × 1.6 mm. The measured results at 915 MHz show a 10 dB return loss bandwidth of 55 MHz, a peak realized gain of - 2.37 dBi in free-space and - 6.1 dBi on-body. The paper concludes by highlighting the potential benefits of 915 MHz operation for future IoT devices.

CARM and harmonic gyro-amplifier experiments at 17 GHz

International Nuclear Information System (INIS)

Menninger, W.L.; Danly, B.G.; Alberti, S.; Chen, C.; Rullier, J.L.; Temkin, R.J.

1993-01-01

Cyclotron resonance maser amplifiers are possible sources for applications such as electron cyclotron resonance heating of fusion plasmas and driving high-gradient rf linear accelerators. For accelerator drivers, amplifiers or phase locked-oscillators are required. A 17 GHz cyclotron autoresonance maser (CARM) amplifier experiment and a 17 GHz third harmonic gyro-amplifier experiment are presently underway at the MIT Plasma Fusion Center. Using the SRL/MIT SNOMAD II introduction accelerator to provide a 380 kV, 180 A, 30 ns flat top electron beam, the gyro-amplifier experiment has produced 5 MW of rf power with over 50 dB of gain at 17 GHz. The gyro-amplifier operates in the TE 31 mode using a third harmonic interaction. Because of its high power output, the gyro-amplifier will be used as the rf source for a photocathode rf electron gun experiment also taking place at MIT. Preliminary gyro-amplifier results are presented, including measurement of rf power, gain versus interaction length, and the far-field pattern. A CARM experiment designed to operate in the TE 11 mode is also discussed

All printed antenna based on silver nanoparticles for 1.8 GHz applications

Science.gov (United States)

Hassan, Arshad; Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

2016-08-01

In this paper, we propose a novel printed antenna for 1.8 GHz band applications. The proposed antenna is made of silver nanoparticle-based radiating element and 0.04-mm thin, transparent and flexible polyethylene terephthalate (PET) substrate. The proposed antenna is designed and simulated by finite-element-method-based high-frequency structure simulator (HFSS). We obtain reflection coefficient of -23 dB, gain of 2.72 dBi and efficiency of 93.33 %. The resonance frequency of the antenna is also verified through national instrument (NI) Multisim simulation on the proposed equivalent circuit. We realize the antenna in a single process by commercial Dimatix material inkjet printer (DMP-3000) at ambient condition and characterize it by using vector network analyzer and spectrum analyzer. The measured reflection coefficient and -10 dB bandwidth are -32.2 dB and 190.5 MHz, respectively, which shows good agreement with HFSS and NI Multisim results. The proposed compact and optimum antenna printed on thin, transparent and fully bendable PET substrate becomes very attractive since it can overcome the limits of cost and size. These results suggest that the proposed antenna is well suitable for electronic devices operating over 1.8 GHz band such as Telos-B and other wearable printed devices.

Compact Microstrip Triple-Mode Bandpass Filters Using Dual-Stub-Loaded Spiral Resonators

Directory of Open Access Journals (Sweden)

K. D. Xu

2017-04-01

Full Text Available Two new microstrip triple-mode resonators loaded with T-shaped open stubs using axially and centrally symmetric spiral structures, respectively, are presented. Spiraled for circuit size reduction, these two half-wavelength resonators can both generate three resonant modes over a wide frequency band by loading two T-stubs with different lengths. Due to the structural symmetry, they can be analyzed by odd- and even-mode method. To validate the design concept, two compact bandpass filters (BPFs using these two novel resonators with center frequencies of 1.76 GHz and 2.44 GHz for the GSM1800 and WLAN/Zigbee applications, respectively, have been designed, fabricated and tested. The center frequencies and bandwidths can be tunable through the analysis of resonant frequency responses, fractional bandwidths and external quality factor versus the resonator parameters. The final measured results have achieved good consistence with the simulations of these two BPFs.

A Compact Size 4–19.1 GHz Heart Shape UWB Antenna with Triangular Patches

Directory of Open Access Journals (Sweden)

Gokmen Isik

2013-01-01

Full Text Available An ultrawideband antenna is designed, simulated, and realized. To overcome the narrow bandwidth characteristics of basic patch antennas, the structure of the radiation pattern is optimized by the aid of elliptical and rectangular patches. Also triangular patches are applied to the antenna edge in order to enhance the VSWR and gain properties. A typical VSWR of 1.5 (less than 2 in the whole frequency range and a typical gain of 2 dBi (mainly above 1 dBi in the whole frequency range are observed. The simulations present that the designed antenna has a bandwidth ratio of ~5 : 1 within the frequency range of 4–19.1 GHz with compact dimensions of 25 × 26 mm2. It is fabricated on a 0.5 mm thick, RO3035 substrate. The input impedance, gain, and radiation characteristics of the antenna are also presented. With these properties, it is verified that, with its novel shape, the proposed antenna can be used for various UWB applications.

Improving the Bandwidth Selection in Kernel Equating

Science.gov (United States)

Andersson, Björn; von Davier, Alina A.

2014-01-01

We investigate the current bandwidth selection methods in kernel equating and propose a method based on Silverman's rule of thumb for selecting the bandwidth parameters. In kernel equating, the bandwidth parameters have previously been obtained by minimizing a penalty function. This minimization process has been criticized by practitioners…

The statistical bandwidth of Butterworth filters

Science.gov (United States)

Davy, J. L.; Dunn, I. P.

1987-06-01

The precision of standard architectural acoustic measurements is a function of the statistical bandwidth of the band pass filters used in the measurements. The International and United States Standards on octave and fractional octave-band filters which specify the band pass filters used in architectural acoustics measurements give the effective bandwidth, but unfortunately not the statistical bandwidth of the filters. Both these Standards are currently being revised and both revisions require the use of Butterworth filter characteristics. In this paper it is shown theoretically that the ratio of statistical bandwidth to effective bandwidth for an nth order Butterworth band pass filter is {2n}/{(2n-1)}. This is verified experimentally for third-octave third-order Butterworth band pass filters. It is also shown experimentally that this formula is approximately correct for some non-Butterworth third-octave third-order band pass filters. Because of the importance of Butterworth filters in the revised Standards, the theory of Butterworth filters is reviewed and the formulae for Butterworth filters given in both revised Standards are derived.

Gain-Enhanced On-Chip Antenna Utilizing Artificial Magnetic Conductor Reflecting Surface at 94 GHz

KAUST Repository

Nafe, Mahmoud

2015-01-01

In this work, the use of specially patterned reflecting surfaces for improving on- chip antenna performance is investigated. By using a periodic metallic surface on top of a grounded substrate, the structure can mimic the behavior of a perfect mag- netic conductor, hence called Artificial Magnetic Conductor (AMC) surface. Unlike conventional ground plane reflecting surfaces, AMC surfaces generally enhance the radiation and impedance characteristics of close-by antennas. Based on this property, a ring-based AMC reflecting surface has been designed in the oxide layer for on-chip antennas operating at 94 GHz. Furthermore, a folded dipole antenna with its associ- ated planar feeding structures has been optimized and integrated with the developed ring-based AMC surface. The proposed design is then fabricated at KAUST clean- room facilities. Prototype characterization showed very promising results with good correlation to simulations, with the antenna exhibiting an impedance bandwidth of 10% (90-100 GHz) and peak gain of -1.4 dBi, which is the highest gain reported for on-chip antennas at this frequency band without the use of any external o↵-chip components or post-fabrication steps.

Design of a 3.7 GHz oscillator for the solid state drive of the LHCD system

International Nuclear Information System (INIS)

Sainkar, Sandeep; Dixit, Harish; Cheeran, Alice; Sharma, P.K.

2017-01-01

The LHCD system is commissioned on the SST-1 tokamak for the current drive. It has a capability to generate power of 2 MW CW at 3.7 GHz and deliver the power to the tokamak via a grill antenna through a phased array of wave guides. The system relies on 4 Klystrons (TH-2103D) each generating 500 kW CW power. The klystrons act as an amplifier providing a gain of 40 dB with a bandwidth of 10 MHz and amplify the input power provided by a solid state driver. The klystron requires a supply of 65 kV and 20A for its operation and has to be extensively conditioned before it can be operated even for obtaining lower power levels. This paper describes the design of oscillator for this system. The oscillator is based on bipolar junction transistor BFR360F. Linear and non-linear analysis has been performed on the design to ascertain its performance. The oscillator delivered a power of 20 mW at 3.7 GHz

Characteristics of ocular temperature elevations after exposure to quasi- and millimeter waves (18-40 GHz)

Science.gov (United States)

Kojima, Masami; Suzuki, Yukihisa; Tsai, Cheng-Yu; Sasaki, Kensuke; Wake, Kanako; Watanabe, Soichi; Taki, Masao; Kamimura, Yoshitsugu; Hirata, Akimasa; Sasaki, Kazuyuki; Sasaki, Hiroshi

2015-04-01

In order to investigate changes in ocular temperature in rabbit eyes exposed to different frequencies (18 to 40 GHz) of quasi-millimeter waves, and millimeter waves (MMW). Pigmented rabbits were anesthetized with both general and topical anesthesia, and thermometer probes (0.5 mm in diameter) were inserted into their cornea (stroma), lens (nucleus) and vitreous (center of vitreous). The eyes were exposed unilaterally to 200 mW/cm2 by horn antenna for 3 min at 18, 22 and 26.5 GHz using a K band exposure system or 26.5, 35 and 40 GHz using a Ka band exposure system. Changes in temperature of the cornea, lens and vitreous were measured with a fluoroptic thermometer. Since the ocular temperatures after exposure to 26.5 GHz generated by the K band and Ka band systems were similar, we assumed that experimental data from these 2 exposure systems were comparable. The highest ocular temperature was induced by 40 GHz MMW, followed by 35 GHz. The 26.5 and 22 GHz corneal temperatures were almost the same. The lowest temperature was recorded at 18 GHz. The elevation in ocular temperature in response to exposure to 200 mW/cm2 MMW is dependent on MMW frequency. MMW exposure induced heat is conveyed not only to the cornea but also the crystalline lens.

47 CFR 2.202 - Bandwidths.

Science.gov (United States)

2010-10-01

... three numerals and one letter. The letter occupies the position of the decimal point and represents the... quality desired Speech and music, M=4000, Bandwidth: 8000 Hz= 8 kHz 8K00A3E Sound broadcasting, single... desired Speech and music, M=4000, Bandwidth: 4000 Hz= 4 kHz 4K00R3E Sound broadcasting, single-sideband...

Gain-Enhanced On-Chip Antenna Utilizing Artificial Magnetic Conductor Reflecting Surface at 94 GHz

KAUST Repository

Nafe, Mahmoud

2015-08-04

Nowadays, there is a growing demand for high frequency-bandwidth mm-wave (30-300 GHz) electronic wireless transceiver systems to support applications such as high data-rate wireless communication and high resolution imaging. Such mm-wave systems are becoming more feasible due to the extreme transistor downscaling in silicon-based integrated circuits, which enabled densely-integrated high-speed elec- tronics operating up to more than 100 GHz with low fabrication cost. To further enhance system integrability, it is required to implement all wireless system compo- nents on the chip. Presently, the last major barrier to true System-on-Chip (SoC) realization is the antenna implementation on the silicon chip. Although at mm-wave frequencies the antenna size becomes small enough to fit on chip, the antenna performance is greatly deteriorated due the high conductivity and high relative permittivity of the silicon substrate. The negative e↵ects of the silicon substrate could be avoided by using a metallic reflecting surface on top of silicon, which e↵ectively isolates the antenna from the silicon. However, this approach has the shortcoming of having to implement the antenna on the usually very thin silicon oxide layer of a typical CMOS fabrication process (10’s of μm). This forces the antenna to be in a very close proximity (less than one hundredth of a wavelength) to the reflecting surface. In this regime, the use of conventional metallic reflecting surface for silicon shielding has severe e↵ects on the antenna performance as it tends to reduce the antenna radiation resistance resulting in most of the energy being absorbed rather than radiated. In this work, the use of specially patterned reflecting surfaces for improving on- chip antenna performance is investigated. By using a periodic metallic surface on top of a grounded substrate, the structure can mimic the behavior of a perfect mag- netic conductor, hence called Artificial Magnetic Conductor (AMC) surface

Controlling Laser Plasma Instabilities Using Temporal Bandwidth

Science.gov (United States)

Tsung, Frank; Weaver, J.; Lehmberg, R.

2016-10-01

We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temporal bandwidth under conditions relevant to current and future experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth (where the inverse bandwidth is comparable with the linear growth time), the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using beam smoothing techniques such as ISI). We will quantify these effects and investigate higher dimensional effects such as laser speckles. This work is supported by DOE and NRL.

Superconducting ECR ion source: From 24-28 GHz SECRAL to 45 GHz fourth generation ECR

Science.gov (United States)

Zhao, H. W.; Sun, L. T.; Guo, J. W.; Zhang, W. H.; Lu, W.; Wu, W.; Wu, B. M.; Sabbi, G.; Juchno, M.; Hafalia, A.; Ravaioli, E.; Xie, D. Z.

2018-05-01

The development of superconducting ECR source with higher magnetic fields and higher microwave frequency is the most straight forward path to achieve higher beam intensity and higher charge state performance. SECRAL, a superconducting third generation ECR ion source, is designed for 24-28 GHz microwave frequency operation with an innovative magnet configuration of sextupole coils located outside the three solenoids. SECRAL at 24 GHz has already produced a number of record beam intensities, such as 40Ar12+ 1.4 emA, 129Xe26+ 1.1 emA, 129Xe30+ 0.36 emA, and 209Bi31+ 0.68 emA. SECRAL-II, an upgraded version of SECRAL, was built successfully in less than 3 years and has recently been commissioned at full power of a 28 GHz gyrotron and three-frequency heating (28 + 45 + 18 GHz). New record beam intensities for highly charged ion production have been achieved, such as 620 eμA 40Ar16+, 15 eμA 40Ar18+, 146 eμA 86Kr28+, 0.5 eμA 86Kr33+, 53 eμA 129Xe38+, and 17 eμA 129Xe42+. Recent beam test results at SECRAL and SECRAL II have demonstrated that the production of more intense highly charged heavy ion beams needs higher microwave power and higher frequency, as the scaling law predicted. A 45 GHz superconducting ECR ion source FECR (a first fourth generation ECR ion source) is being built at IMP. FECR will be the world's first Nb3Sn superconducting-magnet-based ECR ion source with 6.5 T axial mirror field, 3.5 T sextupole field on the plasma chamber inner wall, and 20 kW at a 45 GHz microwave coupling system. This paper will focus on SECRAL performance studies at 24-28 GHz and technical design of 45 GHz FECR, which demonstrates a technical path for highly charged ion beam production from 24 to 28 GHz SECRAL to 45 GHz FECR.

Low noise cryogenic receiver for spectroscopic applications in mm-wave radioastronomy at 230 GHz

International Nuclear Information System (INIS)

Pagani, L.; Ruffie, G.; Beaudin, G.; Gheudin, M.; Deschamps, A.

1986-01-01

A new cooled mm-wave receiver is presented. This receiver has been in operation since October 1985 with a 2.5 m Cassegrain telescope located at the Plateau de Bure in the French Alps. It is tunable from 210 to 240 GHz and has a DSB system noise temperature of 360 K and a 600 MHz instantaneous bandwidth. The receiver is composed of a local oscillator (klystron frequency tripler) and a Schottky diode mixer with a cooled FET amplifier. Quasi-optical techniques are used for signal injection. A computer-controlled microprocessor drives the whole system and performs calibration and frequency tuning of the receiver. The different parts of the receiver, frequency tripler, quasi-optical techniques, mixer, FET amplifier, and microprocessor, are described. 13 references

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

International Nuclear Information System (INIS)

Wessel, J; Schmalz, K; Meliani, C; Gastrock, G; Cahill, B P

2013-01-01

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.

Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

Science.gov (United States)

Li, Hao; Liu, Wenzhong; Zhang, Hao F.

2015-10-01

Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

Open-Loop Wide-Bandwidth Phase Modulation Techniques

Directory of Open Access Journals (Sweden)

Nitin Nidhi

2011-01-01

Full Text Available The ever-increasing growth in the bandwidth of wireless communication channels requires the transmitter to be wide-bandwidth and power-efficient. Polar and outphasing transmitter topologies are two promising candidates for such applications, in future. Both these architectures require a wide-bandwidth phase modulator. Open-loop phase modulation presents a viable solution for achieving wide-bandwidth operation. An overview of prior art and recent approaches for phase modulation is presented in this paper. Phase quantization noise cancellation was recently introduced to lower the out-of-band noise in a digital phase modulator. A detailed analysis on the impact of timing and quantization of the cancellation signal is presented. Noise generated by the transmitter in the receive band frequency poses another challenge for wide-bandwidth transmitter design. Addition of a noise transfer function notch, in a digital phase modulator, to reduce the noise in the receive band during phase modulation is described in this paper.

Secure Fusion Estimation for Bandwidth Constrained Cyber-Physical Systems Under Replay Attacks.

Science.gov (United States)

Chen, Bo; Ho, Daniel W C; Hu, Guoqiang; Yu, Li; Bo Chen; Ho, Daniel W C; Guoqiang Hu; Li Yu; Chen, Bo; Ho, Daniel W C; Hu, Guoqiang; Yu, Li

2018-06-01

State estimation plays an essential role in the monitoring and supervision of cyber-physical systems (CPSs), and its importance has made the security and estimation performance a major concern. In this case, multisensor information fusion estimation (MIFE) provides an attractive alternative to study secure estimation problems because MIFE can potentially improve estimation accuracy and enhance reliability and robustness against attacks. From the perspective of the defender, the secure distributed Kalman fusion estimation problem is investigated in this paper for a class of CPSs under replay attacks, where each local estimate obtained by the sink node is transmitted to a remote fusion center through bandwidth constrained communication channels. A new mathematical model with compensation strategy is proposed to characterize the replay attacks and bandwidth constrains, and then a recursive distributed Kalman fusion estimator (DKFE) is designed in the linear minimum variance sense. According to different communication frameworks, two classes of data compression and compensation algorithms are developed such that the DKFEs can achieve the desired performance. Several attack-dependent and bandwidth-dependent conditions are derived such that the DKFEs are secure under replay attacks. An illustrative example is given to demonstrate the effectiveness of the proposed methods.

Fluid limits for Bandwidth-Sharing Networks with Impatience.

NARCIS (Netherlands)

Remerova, M.; Reed, J.; Zwart, A.P.

2014-01-01

Bandwidth-sharing networks as introduced by Roberts and Massoulié [Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan], Massoulié and Roberts [Massoulié L, Roberts JW (1999) Bandwidth sharing: Objectives and

VEGAS: VErsatile GBT Astronomical Spectrometer

Science.gov (United States)

Bussa, Srikanth; VEGAS Development Team

2012-01-01

The National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program is funding a new spectrometer backend for the Green Bank Telescope (GBT). This spectrometer is being built by the CICADA collaboration - collaboration between the National Radio Astronomy Observatory (NRAO) and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California Berkeley.The backend is named as VErsatile GBT Astronomical Spectrometer (VEGAS) and will replace the capabilities of the existing spectrometers. This backend supports data processing from focal plane array systems. The spectrometer will be capable of processing up to 1.25 GHz bandwidth from 8 dual polarized beams or a bandwidth up to 10 GHz from a dual polarized beam.The spectrometer will be using 8-bit analog to digital converters (ADC), which gives a better dynamic range than existing GBT spectrometers. There will be 8 tunable digital sub-bands within the 1.25 GHz bandwidth, which will enhance the capability of simultaneous observation of multiple spectral transitions. The maximum spectral dump rate to disk will be about 0.5 msec. The vastly enhanced backend capabilities will support several science projects with the GBT. The projects include mapping temperature and density structure of molecular clouds; searches for organic molecules in the interstellar medium; determination of the fundamental constants of our evolving Universe; red-shifted spectral features from galaxies across cosmic time and survey for pulsars in the extreme gravitational environment of the Galactic Center.

Study of paramagnetic defect centers in as-grown and annealed TiO2 anatase and rutile nanoparticles by a variable-temperature X-band and high-frequency (236 GHz) EPR.

Science.gov (United States)

Misra, S K; Andronenko, S I; Tipikin, D; Freed, J H; Somani, V; Prakash, Om

2016-03-01

Detailed EPR investigations on as-grown and annealed TiO 2 nanoparticles in the anatase and rutile phases were carried out at X-band (9.6 GHz) at 77, 120-300 K and at 236 GHz at 292 K. The analysis of EPR data for as-grown and annealed anatase and rutile samples revealed the presence of several paramagnetic centers: Ti 3+ , O - , adsorbed oxygen (O 2 - ) and oxygen vacancies. On the other hand, in as-grown rutile samples, there were observed EPR lines due to adsorbed oxygen (O 2 - ) and the Fe 3+ ions in both Ti 4+ substitutional positions, with and without coupling to an oxygen vacancy in the near neighborhood. Anatase nanoparticles were completely converted to rutile phase when annealed at 1000° C, exhibiting EPR spectra similar to those exhibited by the as-grown rutile nanoparticles. The high-frequency (236 GHz) EPR data on anatase and rutile samples, recorded in the region about g = 2.0 exhibit resolved EPR lines, due to O - and O 2 - ions enabling determination of their g-values with higher precision, as well as observation of hyperfine sextets due to Mn 2+ and Mn 4+ ions in anatase.

Directing Traffic: Managing Internet Bandwidth Fairly

Science.gov (United States)

Paine, Thomas A.; Griggs, Tyler J.

2008-01-01

Educational institutions today face budgetary restraints and scarce resources, complicating the decision of how to allot bandwidth for campus network users. Additionally, campus concerns over peer-to-peer networking (specifically outbound Internet traffic) have increased because of bandwidth and copyright issues. In this article, the authors…

Novel miniature high power ring filter

International Nuclear Information System (INIS)

Huang Huifen; Mao Junfa; Luo Zhihua

2005-01-01

The power handling capability of high temperature superconducting (HTS) filters is limited due to current concentration at the edges of the superconducting films. This problem can be overcome by using ring resonator, which employs the edge current free and reduces the current concentration. However, this kind of filter has large size. In order to reduce the cost and size and increase the power handling capability, in this paper a HTS photonic bandgap (PBG) structure filter is developed. The proposed pass band filter with PBG structure exhibits center frequency 12.23 GHz, steepness (about 35 dB/GHz), bandwidth (-3 dB bandwidth is 0.045 GHz), and low insertion loss (about -0.5 dB), and can handle input power up to 1 W (this value was limited by the measurement instrument used in the experiment). The size is reduced by 25%, insertion loss reduced by 37.5%, and steeper roll-off of the filter is also obtained compared with that in published literature

A compact high-gradient 25 MeV 17 GHz RF linac for free-electron laser research

International Nuclear Information System (INIS)

Danly, B.G.; Chen, S.C.; Kreischer, K.E.

1995-01-01

A new compact high-gradient (60 MeV/m) high-frequency (17.136 GHz) RF linac is presently under construction by Haimson Research Corp. (HRC) for installation at the MIT Plasma Fusion Center in the High-Gradient Accelerator and High Power Microwave Laboratory. This accelerator will utilize an existing traveling-wave relativistic klystron (TWRK) which is now operation at MIT with 25 MW power, 67 dB gain, and 52% efficiency at 17.136 GHz

Coherent Optical Generation of a 6 GHz Microwave Signal with Directly Phase Locked Semiconductor DFB Lasers

DEFF Research Database (Denmark)

Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Bruun, Marlene

1992-01-01

Experimental results of a wideband heterodyne second order optical phase locked loop with 1.5 ¿m semiconductor lasers are presented. The loop has a bandwidth of 180 MHz, a gain of 181 dBHz and a propagation delay of only 400 ps. A beat signal of 8 MHz linewidth is phase locked to become a replica...... of a microwave reference source close to carrier with a noise level of ¿125 dBc/Hz. The total phase variance of the locked carrier is 0.04 rad2 and carriers can be generated in a continuous range from 3 to 18 GHz. The loop reliability is excellent with an average time to cycle slip of 1011 seconds...

Wideband Array for C, X, and Ku-Band Applications with 5.3:1 Bandwidth

Science.gov (United States)

Novak, Markus H.; Volakis, John L.; Miranda, Felix A.

2015-01-01

Planar arrays that exploit strong intentional coupling between elements have allowed for very wide bandwidths in low-profile configurations. However, such designs also require complex impedance matching networks that must also be very compact. For many space applications, typically occurring at C-, X-, Ku-, and most recently at Ka-band, such designs require specialized and expensive fabrication techniques. To address this issue, a novel ultra-wideband array is presented, using a simplified feed network to reduce fabrication cost. The array operates from 3.5-18.5 GHz with VSWR less than 2.4 at broadside, and is of very low profile, having a total height of lambda/10 at the lowest frequency of operation. Validation is provided using a 64-element prototype array, fabricated using common Printed Circuit Board (PCB) technology. The low size, weight, and cost of this array make it attractive for space-borne applications.

A GPU-Based Wide-Band Radio Spectrometer

Science.gov (United States)

Chennamangalam, Jayanth; Scott, Simon; Jones, Glenn; Chen, Hong; Ford, John; Kepley, Amanda; Lorimer, D. R.; Nie, Jun; Prestage, Richard; Roshi, D. Anish; Wagner, Mark; Werthimer, Dan

2014-12-01

The graphics processing unit has become an integral part of astronomical instrumentation, enabling high-performance online data reduction and accelerated online signal processing. In this paper, we describe a wide-band reconfigurable spectrometer built using an off-the-shelf graphics processing unit card. This spectrometer, when configured as a polyphase filter bank, supports a dual-polarisation bandwidth of up to 1.1 GHz (or a single-polarisation bandwidth of up to 2.2 GHz) on the latest generation of graphics processing units. On the other hand, when configured as a direct fast Fourier transform, the spectrometer supports a dual-polarisation bandwidth of up to 1.4 GHz (or a single-polarisation bandwidth of up to 2.8 GHz).

Underwater Communications for Video Surveillance Systems at 2.4 GHz

Directory of Open Access Journals (Sweden)

Sandra Sendra

2016-10-01

Full Text Available Video surveillance is needed to control many activities performed in underwater environments. The use of wired media can be a problem since the material specially designed for underwater environments is very expensive. In order to transmit the images and videos wirelessly under water, three main technologies can be used: acoustic waves, which do not provide high bandwidth, optical signals, although the effect of light dispersion in water severely penalizes the transmitted signals and therefore, despite offering high transfer rates, the maximum distance is very small, and electromagnetic (EM waves, which can provide enough bandwidth for video delivery. In the cases where the distance between transmitter and receiver is short, the use of EM waves would be an interesting option since they provide high enough data transfer rates to transmit videos with high resolution. This paper presents a practical study of the behavior of EM waves at 2.4 GHz in freshwater underwater environments. First, we discuss the minimum requirements of a network to allow video delivery. From these results, we measure the maximum distance between nodes and the round trip time (RTT value depending on several parameters such as data transfer rate, signal modulations, working frequency, and water temperature. The results are statistically analyzed to determine their relation. Finally, the EM waves’ behavior is modeled by a set of equations. The results show that there are some combinations of working frequency, modulation, transfer rate and temperature that offer better results than others. Our work shows that short communication distances with high data transfer rates is feasible.

Superconducting microwave electronics at Lewis Research Center

Science.gov (United States)

Warner, Joseph D.; Bhasin, Kul B.; Leonard, Regis F.

Over the last three years, NASA Lewis Research Center has investigated the application of newly discovered high temperature superconductors to microwave electronics. Using thin films of YBa2Cu3O7-delta and Tl2Ca2Ba2Cu3Ox deposited on a variety of substrates, including strontium titanate, lanthanum gallate, lanthanum aluminate and magnesium oxide, a number of microwave circuits have been fabricated and evaluated. These include a cavity resonator at 60 GHz, microstrip resonators at 35 GHz, a superconducting antenna array at 35 GHz, a dielectric resonator at 9 GHz, and a microstrip filter at 5 GHz. Performance of some of these circuits as well as suggestions for other applications are reported.

Superconducting Microwave Electronics at Lewis Research Center

Science.gov (United States)

Warner, Joseph D.; Bhasin, Kul B.; Leonard, Regis F.

1991-01-01

Over the last three years, NASA Lewis Research Center has investigated the application of newly discovered high temperature superconductors to microwave electronics. Using thin films of YBa2Cu3O7-delta and Tl2Ca2Ba2Cu3Ox deposited on a variety of substrates, including strontium titanate, lanthanum gallate, lanthanum aluminate and magnesium oxide, a number of microwave circuits have been fabricated and evaluated. These include a cavity resonator at 60 GHz, microstrip resonators at 35 GHz, a superconducting antenna array at 35 GHz, a dielectric resonator at 9 GHz, and a microstrip filter at 5 GHz. Performance of some of these circuits as well as suggestions for other applications are reported.

Low and Expensive Bandwidth Remains Key Bottleneck for ...

African Journals Online (AJOL)

These bottlenecks have dwarfed the expectations of the citizens to fully participate in the new world economic order galvanized by e-commerce and world trade. It is estimated that M.I.T in Boston USA has bandwidth allocation that surpasses all the bandwidth allocated to Nigeria put together. Low bandwidth has been found ...

High-bandwidth memory interface

CERN Document Server

Kim, Chulwoo; Song, Junyoung

2014-01-01

This book provides an overview of recent advances in memory interface design at both the architecture and circuit levels. Coverage includes signal integrity and testing, TSV interface, high-speed serial interface including equalization, ODT, pre-emphasis, wide I/O interface including crosstalk, skew cancellation, and clock generation and distribution. Trends for further bandwidth enhancement are also covered.   • Enables readers with minimal background in memory design to understand the basics of high-bandwidth memory interface design; • Presents state-of-the-art techniques for memory interface design; • Covers memory interface design at both the circuit level and system architecture level.

6‐GHz‐to‐18‐GHz AlGaN/GaN Cascaded Nonuniform Distributed Power Amplifier MMIC Using Load Modulation of Increased Series Gate Capacitance

Directory of Open Access Journals (Sweden)

Dong‐Hwan Shin

2017-10-01

Full Text Available A 6‐GHz‐to‐18‐GHz monolithic nonuniform distributed power amplifier has been designed using the load modulation of increased series gate capacitance. This amplifier was implemented using a 0.25‐μm AlGaN/GaN HEMT process on a SiC substrate. With the proposed load modulation, we enhanced the amplifier's simulated performance by 4.8 dB in output power, and by 13.1% in power‐added efficiency (PAE at the upper limit of the bandwidth, compared with an amplifier with uniform gate coupling capacitors. Under the pulse‐mode condition of a 100‐μs pulse period and a 10% duty cycle, the fabricated power amplifier showed a saturated output power of 39.5 dBm (9 W to 40.4 dBm (11 W with an associated PAE of 17% to 22%, and input/output return losses of more than 10 dB within 6 GHz to 18 GHz.

Bandwidth Assessment for MultiRotor UAVs

Directory of Open Access Journals (Sweden)

Ferrarese Gastone

2017-06-01

Full Text Available This paper is a technical note about the theoretical evaluation of the bandwidth of multirotor helicopters. Starting from a mathematical linear model of the dynamics of a multirotor aircraft, the transfer functions of the state variables that deeply affect the stability characteristics of the aircraft are obtained. From these transfer functions, the frequency response analysis of the system is effected. After this analysis, the bandwidth of the system is defined. This result is immediately utilized for the design of discrete PID controllers for hovering flight stabilization. Numeric simulations are shown to demonstrate that the knowledge of the bandwidth is a valid aid in the design of flight control systems of these machines.

A 30 GHz 5-TeV Linear Collider

International Nuclear Information System (INIS)

Wilson, Perry B

2003-01-01

We present parameters for a linear collider with a 3 to 5 TeV center-of-mass energy that utilizes conventional rf technology operating at a frequency around 30 GHz. We discuss the scaling laws and assumed limitations that lead to the parameters described and we compare the merits and liabilities of different technological options including rf power source, accelerator structure, and final focus system design. Finally, we outline the components of the collider while specifying the required alignment and construction tolerances

A Compact Kapton-based Inkjet Printed Multiband Antenna for Flexible Wireless Devices

KAUST Repository

Ahmed, Sana; Tahir, Farooq; Shamim, Atif; Cheema, Hammad M.

2015-01-01

Kapton polyimide-based flexible substrate with dimensions of 70 x 70 x 0.11 mm3. The antenna covers four wide frequency bands with measured impedance bandwidths of 54.4%, 14%, 23.5% and 17.2%, centered at 1.2, 2.0, 2.6 and 3.4 GHz, respectively, thus

154 GHz collective Thomson scattering in LHD

Science.gov (United States)

Tanaka, K.; Nishiura, M.; Kubo, S.; Shimozuma, T.; Saito, T.; Moseev, D.; Abramovic, I.

2018-01-01

Collective Thomson scattering (CTS) was developed by using a 154 GHz gyrotron, and the first data has been obtained. Already, 77 GHz CTS has worked successfully. However, in order to access higher density region, 154 GHz option enhances the usability that reduces the refraction effect, which deteriorates in the local measurements. The system in the down converted frequency was almost identical to the system for 77 GHz. Probing beam, a notch filter, a mixer, and a local oscillator in the receiver system for 77 GHz option were replaced to those for the 154 GHz option. 154 GHz gyrotron was originally prepared for the second harmonic electron cyclotron heating (ECRH) at 2.75 T. However, scattering signal was masked by the second harmonic electron cyclotron emission (ECE) at 2.75 T. Therefore, 154 GHz CTS was operated at 1.375 T with fourth harmonic ECE, and an acceptable signal to noise ratio was obtained. There is a signature of fast ion components with neutral beam (NB) injection. In addition, the CTS spectrum became broader in hydrogen discharge than in deuterium discharge, as the theoretical CTS spectrum expects. This observation indicates a possibility to identify ion species ratio by the 154 GHz CTS diagnostic.

Optical Interconnects for Future Data Center Networks

CERN Document Server

Bergman, Keren; Tomkos, Ioannis

2013-01-01

Optical Interconnects for Future Data Center Networks covers optical networks and how they can provide high bandwidth, energy efficient interconnects with increased communication bandwidth. This volume, with contributions from leading researchers in the field, presents an integrated view of the expected future requirements of data centers and serves as a reference for some of the most advanced and promising solutions proposed by researchers from leading universities, research labs, and companies. The work also includes several novel architectures, each demonstrating different technologies such as optical circuits, optical switching, MIMO optical OFDM, and others. Additionally, Optical Interconnects for Future Data Center Networks provides invaluable insights into the benefits and advantages of optical interconnects and how they can be a promising alternative for future data center networks.

Stochastic Channel Modeling for Railway Tunnel Scenarios at 25 GHz

Directory of Open Access Journals (Sweden)

Danping He

2018-02-01

Full Text Available More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high‐data‐rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the “Mobile Hotspot Network” system, a three‐dimensional ray tracer (RT is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500‐MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd‐Generation‐Partnership‐Project‐like stochastic channel generator. The necessary channel information can be practically realized, which can support the link‐level and system‐level design of the communication system in similar scenarios.

Integrated 60GHz RF beamforming in CMOS

CERN Document Server

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

1-Gb/s zero-pole cancellation CMOS transimpedance amplifier for Gigabit Ethernet applications

Energy Technology Data Exchange (ETDEWEB)

Huang Beiju; Zhang Xu; Chen Hongda, E-mail: bjhuang@semi.ac.c [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2009-10-15

A zero-pole cancellation transimpedance amplifier (TIA) has been realized in 0.35 {mu}m RF CMOS technology for Gigabit Ethernet applications. The TIA exploits a zero-pole cancellation configuration to isolate the input parasitic capacitance including photodiode capacitance from bandwidth deterioration. Simulation results show that the proposed TIA has a bandwidth of 1.9 GHz and a transimpedance gain of 65 dB{center_dot}{Omega} for 1.5 pF photodiode capacitance, with a gain-bandwidth product of 3.4 THz{center_dot}{Omega}. Even with 2 pF photodiode capacitance, the bandwidth exhibits a decline of only 300 MHz, confirming the mechanism of the zero-pole cancellation configuration. The input resistance is 50 {Omega}, and the average input noise current spectral density is 9.7 pA/{radical}Hz. Testing results shows that the eye diagram at 1 Gb/s is wide open. The chip dissipates 17 mW under a single 3.3 V supply.

EMG-Torque Dynamics Change With Contraction Bandwidth.

Science.gov (United States)

Golkar, Mahsa A; Jalaleddini, Kian; Kearney, Robert E

2018-04-01

An accurate model for ElectroMyoGram (EMG)-torque dynamics has many uses. One of its applications which has gained high attention among researchers is its use, in estimating the muscle contraction level for the efficient control of prosthesis. In this paper, the dynamic relationship between the surface EMG and torque during isometric contractions at the human ankle was studied using system identification techniques. Subjects voluntarily modulated their ankle torque in dorsiflexion direction, by activating their tibialis anterior muscle, while tracking a pseudo-random binary sequence in a torque matching task. The effects of contraction bandwidth, described by torque spectrum, on EMG-torque dynamics were evaluated by varying the visual command switching time. Nonparametric impulse response functions (IRF) were estimated between the processed surface EMG and torque. It was demonstrated that: 1) at low contraction bandwidths, the identified IRFs had unphysiological anticipatory (i.e., non-causal) components, whose amplitude decreased as the contraction bandwidth increased. We hypothesized that this non-causal behavior arose, because the EMG input contained a component due to feedback from the output torque, i.e., it was recorded from within a closed-loop. Vision was not the feedback source since the non-causal behavior persisted when visual feedback was removed. Repeating the identification using a nonparametric closed-loop identification algorithm yielded causal IRFs at all bandwidths, supporting this hypothesis. 2) EMG-torque dynamics became faster and the bandwidth of system increased as contraction modulation rate increased. Thus, accurate prediction of torque from EMG signals must take into account the contraction bandwidth sensitivity of this system.

Average Bandwidth Allocation Model of WFQ

Directory of Open Access Journals (Sweden)

Tomáš Balogh

2012-01-01

Full Text Available We present a new iterative method for the calculation of average bandwidth assignment to traffic flows using a WFQ scheduler in IP based NGN networks. The bandwidth assignment calculation is based on the link speed, assigned weights, arrival rate, and average packet length or input rate of the traffic flows. We prove the model outcome with examples and simulation results using NS2 simulator.

Test facility for investigation of heating of 30 GHz accelerating structure imitator for the CLIC project

International Nuclear Information System (INIS)

Elzhov, A.V.; Ginzburg, N.S.; Kaminsky, A.K.; Kuzikov, S.V.; Perelstein, E.A.; Peskov, N.Yu.; Petelin, M.I.; Sedykh, S.N.; Sergeev, A.P.; Sergeev, A.S.; Syratchev, I.; Zaitsev, N.I.

2004-01-01

Since 2001 an experimental test facility for investigation of lifetime of a copper material, with respect to multiple RF pulse actions, was set up on the basis of the JINR (Dubna) FEM oscillator, in collaboration with IAP RAS (Nizhny Novgorod). A high-Q copper cavity, which simulates the parameters of the accelerating structure of the collider CLIC at an operating frequency of 30 GHz, is used in the investigation. The experimental setup consists of a wavebeam injector--FEM oscillator (power of ∼25 MW, pulse duration up to 200 ns, spectral bandwidth not higher than 0.1%), a quasi-optic two-mirror transmission line, a wave-type converter, and a testing cavity. The frequency and transmission features of the components of the quasi-optic line were analyzed

Energy efficiency in elastic-bandwidth optical networks

DEFF Research Database (Denmark)

Vizcaino, Jorge Lopez; Ye, Yabin; Tafur Monroy, Idelfonso

2011-01-01

of elastic bandwidth allocation, opens new horizons in the operation of optical networks. In this paper, we compare the network planning problem in an elastic bandwidth CO-OFDM-based network and a fixed-grid WDM network. We highlight the benefits that bandwidth elasticity and the selection of different......The forecasted growth in the Internet traffic has made the operators and industry to be concerned about the power consumption of the networks, and to become interested in alternatives to plan and operate the networks in a more energy efficient manner. The introduction of OFDM, and its property...

On semidefinite programming bounds for graph bandwidth

NARCIS (Netherlands)

de Klerk, E.; Nagy, M.; Sotirov, R.

2013-01-01

In this paper, we propose two new lower bounds on graph bandwidth and cyclic bandwidth based on semidefinite programming (SDP) relaxations of the quadratic assignment problem. We compare the new bounds with two other SDP bounds reported in [A. Blum, G. Konjevod, R. Ravi, and S. Vempala,

47 CFR 74.535 - Emission and bandwidth.

Science.gov (United States)

2010-10-01

... digital modulation in paragraph (a) of this section, the resolution bandwidth (BRES) of the measuring...), adjusted upward to the nearest greater resolution bandwidth available on the measuring equipment. In all... frequency energy outside the assigned channel. Upon notice by the FCC to the station licensee that...

Experiences in Traceroute and Bandwidth Change Analysis

Energy Technology Data Exchange (ETDEWEB)

Logg, C

2004-06-23

SLAC has been studying end-to-end WAN bandwidth availability and achievability for 2.5 years via IEPM-BW [1]. IEPM-BW performs network intensive tests every 90 minutes. Based on that experience we have also developed a light weight available bandwidth (ABwE [2]) measurement tool that can make a measurement within a second. We are now extending this to a WAN measurement and detection system (IEPM-LITE) aimed at more quickly detecting and troubleshooting network performance problems and also to be more friendly on lower performance paths. IEPM-LITE uses ping, forward traceroutes, and ABwE sensors to monitor, in close to real-time, Round Trip Times (RTT), changes in available bandwidth and routes to and from target hosts. This paper discusses the experiences, techniques and algorithms used to detect and report on significant traceroute and bandwidth changes. The ultimate aim is to develop a lightweight WAN network performance monitoring system that can detect, in near real time, significant changes and generate alerts.

Experiences in Traceroute and Bandwidth Change Analysis

International Nuclear Information System (INIS)

Logg, C

2004-01-01

SLAC has been studying end-to-end WAN bandwidth availability and achievability for 2.5 years via IEPM-BW [1]. IEPM-BW performs network intensive tests every 90 minutes. Based on that experience we have also developed a light weight available bandwidth (ABwE [2]) measurement tool that can make a measurement within a second. We are now extending this to a WAN measurement and detection system (IEPM-LITE) aimed at more quickly detecting and troubleshooting network performance problems and also to be more friendly on lower performance paths. IEPM-LITE uses ping, forward traceroutes, and ABwE sensors to monitor, in close to real-time, Round Trip Times (RTT), changes in available bandwidth and routes to and from target hosts. This paper discusses the experiences, techniques and algorithms used to detect and report on significant traceroute and bandwidth changes. The ultimate aim is to develop a lightweight WAN network performance monitoring system that can detect, in near real time, significant changes and generate alerts

Efficient Bandwidth Management for Ethernet Passive Optical Networks

KAUST Repository

Elrasad, Amr

2016-01-01

The increasing bandwidth demands in access networks motivates network operators, networking devices manufacturers, and standardization institutions to search for new approaches for access networks. These approaches should support higher bandwidth

Optimization of Planar Monopole Wideband Antenna for Wireless Communication System.

Science.gov (United States)

Shakib, Mohammed Nazmus; Moghavvemi, Mahmoud; Mahadi, Wan Nor Liza

2016-01-01

In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is compatible with a good number of wireless standards, including UWB band, Wimax 5.4 GHz band, MVDDS (12.2-12.7GHz), and close range radar and satellite communication in the X-band (8-12GHz), and Ku band (12-18GHz).

Efficient broadband third harmonic frequency conversion via angular dispersion

International Nuclear Information System (INIS)

Pennington, D.M.; Henesian, M.A.; Milam, D.; Eimerl, D.

1995-01-01

In this paper we present experimental measurements and theoretical modeling of third harmonic (3ω) conversion efficiency with optical bandwidth. Third harmonic conversion efficiency drops precipitously as the input bandwidth significantly exceeds the phase matching limitations of the conversion crystals. For Type I/Type II frequency tripling, conversion efficiency be-gins to decrease for bandwidths greater than ∼60 GHz. However, conversion efficiency corresponding to monochromatic phase-matched beams can be recovered provided that the instantaneous Propagation vectors are phase matched at all times. This is achieved by imposing angular spectral dispersion (ASD) on the input beam via a diffraction grating, with a dispersion such that the phase mismatch for each frequency is zero. Experiments were performed on the Optical Sciences Laser (OSL), a 1--100 J class laser at LLNL. These experiments used a 200 GHz bandwidth source produced by a multipassed electro-optic phase modulator. The spectrum produced was composed of discrete frequency components spaced at 3 GHz intervals. Angular dispersion was incorporated by the addition of a 1200 gr/mm diffraction grating oriented at the Littrow angle, and capable of rotation about the beam direction. Experiments were performed with a pulse length of 1-ns and a 1ω input intensity of ∼ 4 GW/cm 2 for near optimal dispersion for phase matching, 5.2 μrad/GHz, with 0.1, 60, and 155 GHz bandwidth, as well as for partial dispersion compensation, 1.66 μrad/GHz, with 155 GHz and 0.1 GHz bandwidth. The direction of dispersion was varied incrementally 360 degrees about the beam diameter. The addition of the grating to the beamline reduced the narrowband conversion efficiency by approximately 10%

Transmission Line for 258 GHz Gyrotron DNP Spectrometry

Science.gov (United States)

Bogdashov, Alexandr A.; Belousov, Vladimir I.; Chirkov, Alexey V.; Denisov, Gregory G.; Korchagin, Vyacheslav V.; Kornishin, Sergey Yu.; Tai, Evgeny M.

2011-06-01

We describe the design and test results of the transmission line for liquid-state (LS) and solid-state (SS) DNP spectrometers with the second-harmonic 258.6 GHz gyrotron at the Institute of the Biophysical Chemistry Center of Goethe University (Frankfurt). The 13-meter line includes a mode converter, HE11 waveguides, 4 mitre bends, a variable polarizer-attenuator, directional couplers, a water-flow calorimeter and a mechanical switch. A microwave power of about 15 W was obtained in the pure HE11 mode at the spectrometer inputs.

Chemical Industry Bandwidth Study

Energy Technology Data Exchange (ETDEWEB)

none,

2006-12-01

The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

Wideband dual frequency modified ellipse shaped patch antenna for WLAN/Wi-MAX/UWB application

Science.gov (United States)

Jain, P. K.; Jangid, K. G.; R. Sharma, B.; Saxena, V. K.; Bhatnagar, D.

2018-05-01

This paper communicates the design and performance of microstrip line fed modified ellipses shaped radiating patch with defected ground structure. Wide impedance bandwidth performance is achieved by applying a pentagonal slot and T slot structure in ground plane. By inserting two semi ellipses shaped ring in ground, we obtained axial ratio bandwidth approx 600 MHz. The proposed antenna is simulated by utilizing CST Microwave Studio simulator 2014. This antenna furnishes wide impedance bandwidth approx. 4.23 GHz, which has spread into two bands 2.45 GHz - 5.73 GHz and 7.22 GHz - 8.17 GHz with nearly flat gain in operating frequency range. This antenna may be proved as a practicable structure for modern wireless communication systems including Wi-MAX, WLAN and lower band of UWB.

SiGe HBT cryogenic preamplification for higher bandwidth donor spin read-out

Science.gov (United States)

Curry, Matthew; Carr, Stephen; Ten-Eyck, Greg; Wendt, Joel; Pluym, Tammy; Lilly, Michael; Carroll, Malcolm

2014-03-01

Single-shot read-out of a donor spin can be performed using the response of a single-electron-transistor (SET). This technique can produce relatively large changes in current, on the order of 1 (nA), to distinguish between the spin states. Despite the relatively large signal, the read-out time resolution has been limited to approximately 100 (kHz) of bandwidth because of noise. Cryogenic pre-amplification has been shown to extend the response of certain detection circuits to shorter time resolution and thus higher bandwidth. We examine a SiGe HBT circuit configuration for cryogenic preamplification, which has potential advantages over commonly used HEMT configurations. Here we present 4 (K) measurements of a circuit consisting of a Silicon-SET inline with a Heterojunction-Bipolar-Transistor (HBT). We compare the measured bandwidth with and without the HBT inline and find that at higher frequencies the signal-to-noise-ratio (SNR) with the HBT inline exceeds the SNR without the HBT inline. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

Wide Bandpass and Narrow Bandstop Microstrip Filters based on Hilbert fractal geometry: design and simulation results.

Directory of Open Access Journals (Sweden)

Yaqeen S Mezaal

Full Text Available This paper presents new Wide Bandpass Filter (WBPF and Narrow Bandstop Filter (NBSF incorporating two microstrip resonators, each resonator is based on 2nd iteration of Hilbert fractal geometry. The type of filter as pass or reject band has been adjusted by coupling gap parameter (d between Hilbert resonators using a substrate with a dielectric constant of 10.8 and a thickness of 1.27 mm. Numerical simulation results as well as a parametric study of d parameter on filter type and frequency responses are presented and studied. WBPF has designed at resonant frequencies of 2 and 2.2 GHz with a bandwidth of 0.52 GHz, -28 dB return loss and -0.125 dB insertion loss while NBSF has designed for electrical specifications of 2.37 GHz center frequency, 20 MHz rejection bandwidth, -0.1873 dB return loss and 13.746 dB insertion loss. The proposed technique offers a new alternative to construct low-cost high-performance filter devices, suitable for a wide range of wireless communication systems.

Strategic Control of 60 GHz Millimeter-Wave High-Speed Wireless Links for Distributed Virtual Reality Platforms

Directory of Open Access Journals (Sweden)

Joongheon Kim

2017-01-01

Full Text Available This paper discusses the stochastic and strategic control of 60 GHz millimeter-wave (mmWave wireless transmission for distributed and mobile virtual reality (VR applications. In VR scenarios, establishing wireless connection between VR data-center (called VR server (VRS and head-mounted VR device (called VRD allows various mobile services. Consequently, utilizing wireless technologies is obviously beneficial in VR applications. In order to transmit massive VR data, the 60 GHz mmWave wireless technology is considered in this research. However, transmitting the maximum amount of data introduces maximum power consumption in transceivers. Therefore, this paper proposes a dynamic/adaptive algorithm that can control the power allocation in the 60 GHz mmWave transceivers. The proposed algorithm dynamically controls the power allocation in order to achieve time-average energy-efficiency for VR data transmission over 60 GHz mmWave channels while preserving queue stabilization. The simulation results show that the proposed algorithm presents desired performance.

Large bandwidth RGC transimpedance preamplifier design in SCA

International Nuclear Information System (INIS)

Wang Ke; Wang Zheng; Liu Zhen'an; Wei Wei; Lu Weiguo; Gary Varner

2009-01-01

A Large Bandwidth RGC Transimpedance Preamplifier is designed for amplifying the high-fidelity timing signal in Switch Capacitance Array chip application. This amplifier have characteristics of low input impedance, large bandwidth, high transimpedance. It will be made under TSMC 0.25μm CMOS technology, and the supply voltage is single 2.5 V. Simulation results indicate: the transimpedance is 5000 ohm, -3dB BW is 953 MHz, and the detector output capacitance have litter effect on the bandwidth in some range. (authors)

On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1–20 GHz

International Nuclear Information System (INIS)

Fannin, P.C.; Vekas, L.; Marin, C.N.; Malaescu, I.

2017-01-01

Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ′(ω, Η)−iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1–20 GHz and polarising fields 0–168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4–6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz. - Highlights: • Complex magnetic susceptibility measurements in the frequency range 0.1–20 GHz. • Determination of the dynamic properties of a transformer oil based ferrofluid. • Wideband attenuator ( Absorber) in the frequency range 2.4–6.3 GHz.

110GHz ECH on DIII-D

International Nuclear Information System (INIS)

Cary, W.P.; Allen, J.C.; Callis, R.W.; Doane, J.L.; Harris, T.E.; Moetler, C.P.; Neren, A.; Prater, P.; Rensen, D.

1992-01-01

This paper reports on a new high power electron cyclotron heating (ECH) system which has been introduced on DIII-D. This system is designed to operate at 110 GHz with a total output power of 2 MW. The system consists of four Varian VGT-8011 gyrotrons (output power of 500 kW), and their associated support equipment. All components have been designed for up to a 10 second pulse duration. The 110 GHz system is intended to further progress in rf current drive experiments on DIII-D when used in conjunction with the existing 60 GHz ECH (1. 6 MW) , and the 30-60 MHz ICH (2MW) systems. H-mode physics, plasma stabilization experiments and transport studies are also to be conducted at 110 GHz

PIC Simulation of Laser Plasma Interactions with Temporal Bandwidths

Science.gov (United States)

Tsung, Frank; Weaver, J.; Lehmberg, R.

2015-11-01

We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temperal bandwidths under conditions relevant to current and future shock ignition experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth, the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using smoothing techniques such as SSD or ISI). We will show that temporal bandwidth along play an important role in the control of LPI's in these lasers and discuss future directions. This work is conducted under the auspices of NRL.

A 60 GHz Frequency Generator Based on a 20 GHz Oscillator and an Implicit Multiplier

NARCIS (Netherlands)

Zong, Z.; Babaie, M.; Staszewski, R.B.

2016-01-01

This paper proposes a mm-wave frequency generation technique that improves its phase noise (PN) performance and power efficiency. The main idea is that a fundamental 20 GHz signal and its sufficiently strong third harmonic at 60 GHz are generated simultaneously in a single oscillator. The desired 60

Test facility for investigation of heating of 30 GHz accelerating structure imitator for the CLIC project

CERN Document Server

Elzhov, A V; Kaminsky, A K; Kuzikov, S V; Perelshtejn, E A; Peskov, N Yu; Petelin, M I; Sedykh, S N; Sergeev, A P; Sergeev, A S; Syratchev, I V; Zaitsev, N I

2004-01-01

Since 2001 an experimental test facility for investigation of lifetime of a copper material, with respect to multiple RF pulse actions, was set up on the basis of the JINR (Dubna) FEM oscillator, in collaboration with IAP RAS (Nizhny Novgorod). A high-Q copper cavity, which simulates the parameters of the accelerating structure of the collider CLIC at an operating frequency of 30GHz, is used in the investigation. The experimental setup consists of a wavebeam injector - FEM oscillator (power of similar to 25MW, pulse duration up to 200ns, spectral bandwidth not higher than 0.1%), a quasi-optic two-mirror transmission line, a wave-type converter, and a testing cavity. The frequency and transmission features of the components of the quasi-optic line were analyzed.

Tunable negative index metamaterial using yttrium iron garnet

International Nuclear Information System (INIS)

He, Yongxue; He, Peng; Dae Yoon, Soack; Parimi, P.V.; Rachford, F.J.; Harris, V.G.; Vittoria, C.

2007-01-01

A magnetic field tunable, broadband, low-loss, negative refractive index metamaterial is fabricated using yttrium iron garnet (YIG) and a periodic array of copper wires. The tunability is demonstrated from 18 to 23 GHz under an applied magnetic field with a figure of merit of 4.2 GHz/kOe. The tuning bandwidth is measured to be 5 GHz compared to 0.9 GHz for fixed field. We measure a minimum insertion loss of 4 dB (or 5.7 dB/cm) at 22.3 GHz. The measured negative refractive index bandwidth is 0.9 GHz compared to 0.5 GHz calculated by the transfer function matrix theory and 1 GHz calculated by finite element simulation

Teleoperation over low bandwidth communication links

International Nuclear Information System (INIS)

Fryer, R.J.; Mair, G.M.; Clark, N.; Heng, J.

1996-01-01

Teleoperation is well established for many areas of hazardous environment working. Where such environments are well structured and contained, such as within a working plant, communications bandwidths need not be a constraining factor. However where the worksite is remote, large, poorly structured or damaged communications rapidly become a critical factor in the efficient deployment and use of teleoperation equipment. The paper justifies and describes means which we are exploring to reduce the required communications bandwidth for teleoperation whist retaining full functionality. Techniques involved include incorporation of local intelligence at the worksite, with bandwidth devoted to high-level up-link control signals and down-link feedback, and the use of highly compressed video feeding 'virtual reality type' HMDs to provide maximum system transparency for the operator. The work is drawing on previous experience with an 'anthropomorphic robot heat' for telepresence work, and proprietary algorithms capable of compressing full colour video to standard telephone modem data rates. (Author)

Fluid Limits for Bandwidth-Sharing Networks in Overload.

NARCIS (Netherlands)

Borst, S.; Egorova, R.; Zwart, A.P.

2014-01-01

Bandwidth-sharing networks as considered by Roberts and Massoulié [28] (Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan) provide a natural modeling framework for describing the dynamic flow-level interaction

Fluid limits for bandwidth-sharing networks in overload

NARCIS (Netherlands)

Borst, S.C.; Egorova, R.R.; Zwart, B.

2014-01-01

Bandwidth-sharing networks as considered by Roberts and Massoulié [28] (Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan) provide a natural modeling framework for describing the dynamic flow-level interaction

Construction of a High Temporal-spectral Resolution Spectrometer for Detection of Fast Transients from Observations of the Sun at 1.4 GHz.

Science.gov (United States)

Casillas-Perez, G. A.; Jeyakumar, S.; Perez-Enriquez, R.

2014-12-01

Transients explosive events with time durations from nanoseconds to several hours, are observed in the Sun at high energy bands such as gamma ray and xray. In the radio band, several types of radio bursts are commonly detected from the ground. A few observations of the Sun in the past have also detected a new class of fast transients which are known to have short-live electromagnetic emissions with durations less than 100 ms. The mechanisms that produce such fast transiets remain unclear. Observations of such fast transients over a wide bandwidth is necessary to uderstand the underlying physical process that produce such fast transients. Due to their very large flux densities, fast radio transients can be observed at high time resolution using small antennas in combination with digital signal processing techniques. In this work we report the progress of an spectrometer that is currently in construction at the Observatorio de la Luz of the Universidad de Guanajuato. The instrument which will have the purpose of detecting solar fast radio transients, involves the use of digital devices such as FPGA and ADC cards, in addition with a receiver with high temporal-spectral resolution centered at 1.4 GHz and a pair of 2.3 m satellite dish.

Sensitivity-Bandwidth Limit in a Multimode Optoelectromechanical Transducer

Science.gov (United States)

Moaddel Haghighi, I.; Malossi, N.; Natali, R.; Di Giuseppe, G.; Vitali, D.

2018-03-01

An optoelectromechanical system formed by a nanomembrane capacitively coupled to an L C resonator and to an optical interferometer has recently been employed for the highly sensitive optical readout of rf signals [T. Bagci et al., Nature (London) 507, 81 (2013), 10.1038/nature13029]. We propose and experimentally demonstrate how the bandwidth of such a transducer can be increased by controlling the interference between two electromechanical interaction pathways of a two-mode mechanical system. With a proof-of-principle device operating at room temperature, we achieve a sensitivity of 300 nV /√{Hz } over a bandwidth of 15 kHz in the presence of radio-frequency noise, and an optimal shot-noise-limited sensitivity of 10 nV /√{Hz } over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multimode transducer can achieve a bandwidth significantly larger than that for a single-mode one.

Broadening the absorption bandwidth of metamaterial absorbers by transverse magnetic harmonics of 210 mode.

Science.gov (United States)

Long, Chang; Yin, Sheng; Wang, Wei; Li, Wei; Zhu, Jianfei; Guan, Jianguo

2016-02-18

By investigating a square-shaped metamaterial structure we discover that wave diffraction at diagonal corners of such a structure excites transverse magnetic harmonics of 210 mode (TM210 harmonics). Multi-layer overlapping and deliberately regulating period length between adjacent unit cells can significantly enhance TM210 harmonics, leading to a strong absorption waveband. On such a basis, a design strategy is proposed to achieve broadband, thin-thickness multi-layered metamaterial absorbers (MMAs). In this strategy big pyramidal arrays placed in the "white blanks" of a chessboard exhibit two isolated absorption bands due to their fundamental and TM210 harmonics, which are further connected by another absorption band from small pyramidal arrays in the "black blanks" of the chessboard. The as-designed MMA at a total thickness (h) of 4.36 mm shows an absorption of above 0.9 in the whole frequency range of 7-18 GHz, which is 38% broader with respect to previous design methods at the same h. This strategy provides an effective route to extend the absorption bandwidth of MMAs without increasing h.

Rectenna Technology Program: Ultra light 2.45 GHz rectenna 20 GHz rectenna

Science.gov (United States)

Brown, William C.

1987-01-01

The program had two general objectives. The first objective was to develop the two plane rectenna format for space application at 2.45 GHz. The resultant foreplane was a thin-film, etched-circuit format fabricated from a laminate composed of 2 mil Kapton F sandwiched between sheets of 1 oz copper. The thin-film foreplane contains half wave dipoles, filter circuits, rectifying Schottky diode, and dc bussing lead. It weighs 160 grams per square meter. Efficiency and dc power output density were measured at 85% and 1 kw/sq m, respectively. Special testing techniques to measure temperature of circuit and diode without perturbing microwave operation using the fluoroptic thermometer were developed. A second objective was to investigate rectenna technology for use at 20 GHz and higher frequencies. Several fabrication formats including the thin-film scaled from 2.45 GHz, ceramic substrate and silk-screening, and monolithic were investigated, with the conclusion that the monolithic approach was the best. A preliminary design of the monolithic rectenna structure and the integrated Schottky diode were made.

Multi-granularity Bandwidth Allocation for Large-Scale WDM/TDM PON

Science.gov (United States)

Gao, Ziyue; Gan, Chaoqin; Ni, Cuiping; Shi, Qiongling

2017-12-01

WDM (wavelength-division multiplexing)/TDM (time-division multiplexing) PON (passive optical network) is being viewed as a promising solution for delivering multiple services and applications, such as high-definition video, video conference and data traffic. Considering the real-time transmission, QoS (quality of services) requirements and differentiated services model, a multi-granularity dynamic bandwidth allocation (DBA) in both domains of wavelengths and time for large-scale hybrid WDM/TDM PON is proposed in this paper. The proposed scheme achieves load balance by using the bandwidth prediction. Based on the bandwidth prediction, the wavelength assignment can be realized fairly and effectively to satisfy the different demands of various classes. Specially, the allocation of residual bandwidth further augments the DBA and makes full use of bandwidth resources in the network. To further improve the network performance, two schemes named extending the cycle of one free wavelength (ECoFW) and large bandwidth shrinkage (LBS) are proposed, which can prevent transmission from interruption when the user employs more than one wavelength. The simulation results show the effectiveness of the proposed scheme.

Bandwidth selection in smoothing functions | Kibua | East African ...

African Journals Online (AJOL)

... inexpensive and, hence, worth adopting. We argue that the bandwidth parameter is determined by two factors: the kernel function and the length of the smoothing region. We give an illustrative example of its application using real data. Keywords: Kernel, Smoothing functions, Bandwidth > East African Journal of Statistics ...

Reconstitution of Low Bandwidth Reaction History

International Nuclear Information System (INIS)

May, M.; Clancy, T.; Fittinghoff, D.; Gennaro, P.; Hagans, K.; Halvorson, G.; Lowry, M.; Perry, T.; Roberson, P.; Smith, D.; Teruya, A.; Blair, J.; Davis, B.; Hunt, E.; Emkeit, B.; Galbraith, J.; Kelly, B.; Montoya, R.; Nickel, G.; Ogle, J.; Wilson, K.; Wood, M.

2004-01-01

The goal of the Test Readiness Program is to transition to a 24 month test readiness posture and if approved move to an 18-month posture. One of the key components of the Test Readiness Program necessary to meet this goal is the reconstitution of the important diagnostics. Since the end of nuclear testing, the ability to field diagnostics on a nuclear test has deteriorated. Reconstitution of diagnostics before those who had experience in nuclear testing either retire or leave is essential to achieving a shorter test readiness posture. Also, the data recording systems have not been used since the end of testing. This report documents the reconstitution of one vital diagnostic: the low bandwidth reaction history diagnostic for FY04. Reaction history is one of the major diagnostics that has been used on all LLNL and LANL tests since the early days of nuclear testing. Reaction history refers to measuring the time history of the gamma and neutron output from a nuclear test. This gives direct information on the nuclear reactions taking place in the device. The reaction history measurements are one of the prime measurements the nuclear weapon scientists use to validate their models of device performance. All tests currently under consideration require the reaction history diagnostic. Thus moving to a shorter test readiness posture requires the reconstitution of the ability to make reaction history measurements. Reconstitution of reaction history was planned to be in two steps. Reaction history measurements that have been used in the past can be broadly placed into two categories. The most common type of reaction history and the one that has been performed on virtually all nuclear tests is termed low bandwidth reaction history. This measurement has a time response that is limited by the bandpass of kilometer length coaxial cables. When higher bandwidth has been required for specific measurements, fiber optic techniques have been used. This is referred to as high-bandwidth

45-GHz and 60-GHz 90 nm CMOS power amplifiers with a fully symmetrical 8-way transformer power combiner

Institute of Scientific and Technical Information of China (English)

Zhengdong JIANG; Kaizhe GUO; Peng HUANG; Yiming FAN; Chenxi ZHAO; Yongling BAN; Jun LIU; Kai KANG

2017-01-01

In this paper,45 GHz and 60 GHz power amplifiers (PAs) with high output power have been successfully designed by using 90 nm CMOS process.The 45 GHz (60 GHz) PA consists of two (four) differential stages.The sizes of transistors have been designed in an appropriate way so as to trade-off gain,efficiency and stability.Due to limited supply voltage and low breakdown voltage of CMOS MOSFET compared with the traditional Ⅲ-Ⅴ technologies,the technique of power combining has been applied to achieve a high output power.In particular,a novel 8-way distributed active transformer power combiner has been proposed for realizing such mm-wave PA.The proposed transformer combiner with a fully symmetrical layout can improve its input impedance balance at mm-wave frequency regime significantly.Taking its advantages of this novel transformer based power combiner,our realized 45 GHz (60 GHz) mm-wave PA has achieved the gain of 20.3 dB (16.8 dB),the maximum PAE of 14.5％ (13.4％) and the saturated output power of 21 dBm (21 dBm) with the 1.2 V supply voltage.

Propagation of 1-THz bandwidth electrical pulses on high Tc superconducting transmission lines

International Nuclear Information System (INIS)

Nuss, M.C.; Mankiewich, P.M.; Howard, R.E.; Harvey, T.E.; Brandle, C.D.; Straugh, B.L.; Smith, P.R.

1989-01-01

The new high temperature superconductors have triggered enormous interest not only because of the unique physics involved but also because of their technical potentials, such as the promise for propagation of extremely short electrical pulses. Superconducting band caps of --20TH z are predicted assuming BCS theory for the superconductor, making lossless propagation of electrical pulses as short as 50 fs possible. Despite microwave measurements at low frequencies of several gigahertz first studies at higher frequencies by Dykaar et al have shown distortion-free propagation of 100-GHz electrical pulses on YBa 2 Cu 3 O 3 (YBCO) lines for --5-mm propagation distance. Results were also reported for aluminum coplanar lines and a YBCO ground plane. The authors report on the propagation of 1-ps electrical pulses (1-THz bandwidth) on YBCO coplanar transmission lines defined on lanthanum gallate (LaGaO 3 ) as a substrate. On LaGaO 3 , YBCO grows highly oriented as on SrTiO 3 . However, unlike SrTiO 3 , LaGaO 3 has a much lower dielectric constant and small losses in the terahertz frequency range. Electrical pulses of --750-fs duration are generated in a radiation-damaged silicon-on-sapphire photoconductive switch integrated into a 20-μm coplanar stripline with 10-μm spacing and excited with 100-fs optical pulses from a CPM laser. An μ1-THz bandwidth electrical contact is made to the YBCO coplanar stripline defined on LaGaO 3 using a flip-chip geometry. They find that electrical pulses broaden only from 750 fs to 1 ps with little loss in amplitude on traveling through their flip-chip input and propagated electrical pulses are probed by electooptic sampling in two small LiTaO 3 crystals separated by 3 mm

Wide-bandwidth bilateral control using two-stage actuator system

International Nuclear Information System (INIS)

Kokuryu, Saori; Izutsu, Masaki; Kamamichi, Norihiro; Ishikawa, Jun

2015-01-01

This paper proposes a two-stage actuator system that consists of a coarse actuator driven by a ball screw with an AC motor (the first stage) and a fine actuator driven by a voice coil motor (the second stage). The proposed two-stage actuator system is applied to make a wide-bandwidth bilateral control system without needing expensive high-performance actuators. In the proposed system, the first stage has a wide moving range with a narrow control bandwidth, and the second stage has a narrow moving range with a wide control bandwidth. By consolidating these two inexpensive actuators with different control bandwidths in a complementary manner, a wide bandwidth bilateral control system can be constructed based on a mechanical impedance control. To show the validity of the proposed method, a prototype of the two-stage actuator system has been developed and basic performance was evaluated by experiment. The experimental results showed that a light mechanical impedance with a mass of 10 g and a damping coefficient of 2.5 N/(m/s) that is an important factor to establish good transparency in bilateral control has been successfully achieved and also showed that a better force and position responses between a master and slave is achieved by using the proposed two-stage actuator system compared with a narrow bandwidth case using a single ball screw system. (author)

60-GHz Millimeter-Wave Radio: Principle, Technology, and New Results

Directory of Open Access Journals (Sweden)

Nan Guo

2006-12-01

Full Text Available The worldwide opening of a massive amount of unlicensed spectra around 60 GHz has triggered great interest in developing affordable 60-GHz radios. This interest has been catalyzed by recent advance of 60-GHz front-end technologies. This paper briefly reports recent work in the 60-GHz radio. Aspects addressed in this paper include global regulatory and standardization, justification of using the 60-GHz bands, 60-GHz consumer electronics applications, radio system concept, 60-GHz propagation and antennas, and key issues in system design. Some new simulation results are also given. Potentials and problems are explained in detail.

Broadband notch filter design for millimeter-wave plasma diagnostics

DEFF Research Database (Denmark)

Furtula, Vedran; Michelsen, Poul; Leipold, Frank

2010-01-01

Notch filters are integrated in plasma diagnostic systems to protect millimeter-wave receivers from intensive stray radiation. Here we present a design of a notch filter with a center frequency of 140 GHz, a rejection bandwidth of ∼ 900 MHz, and a typical insertion loss below 2 dB in the passband...... of ±9 GHz. The design is based on a fundamental rectangular waveguide with eight cylindrical cavities coupled by T-junction apertures formed as thin slits. Parameters that affect the notch performance such as physical lengths and conductor materials are discussed. The excited resonance mode...

Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses.

Science.gov (United States)

Bachschmidt, Theresa J; Sutter, Reto; Jakob, Peter M; Pfirrmann, Christian W A; Nittka, Mathias

2015-06-01

To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal. Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists. A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used. The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla. © 2014 Wiley Periodicals, Inc.

TPROXY dan FILTERING SEBAGAI METODE OPTIMASI PEMAKAIAN BANDWIDTH INTERNET

Directory of Open Access Journals (Sweden)

Sutiyo Sutiyo

2015-04-01

Full Text Available Until now the use of the internet disuatu agencies viewed from the initial planning, use and care, even long-term planning is still not optimal. The main factor lies in the existing human resources, especially in IT personnel and policy makers who do not understand or do not even know at all how your use of the Internet well, optimal, efficient, particularly associated with the consumption of Internet bandwidth. Internet bandwidth capacity greatly affect the speed of web access or other Internet applications. So we need a plan and maintance necessary to obtain good Internet bandwidth consumption efficiency and guaranteed QoS, such as by utilizing Tproxy and filtering methods. TProxy is a development of which has been patched Squid, a proxy to be able to pass traffic without NAT (Network Access Translation. Fitering a firewall system which is used for filtering data packets that do not want filtered dikendaki or akhirmya able to minimize traffic on bandwidth usage. Tproxy and filtering runs on the Linux platform. Linux distributions are often used to Tproxy is a variant Debian, Centos and then to use Mikrotik Filtering. At the end of each request or query from the client or the response of the proxy server does not have meaningful constraints, the bandwidth between the client and the proxy server does not happen limitation, bandwidth capable of running close to capacity including 10 Mbps Ethernet, 100 Mbps, and even a GPS (full speed.

557 GHz Observations of Water Vapor Outflow from VY Canis Majoris and W Hydrae

Science.gov (United States)

Harwit, Martin; Bergin, Edwin A.

2002-02-01

We report the first detection of thermal water vapor emission in the 557 GHz, 110-101 ground-state transition of ortho-H2O toward VY Canis Majoris. In observations obtained with the Submillimeter Wave Astronomy Satellite, we measured a flux of ~450 Jy, in a spectrally resolved line centered on a velocity vLSR=25 km s-1 with an FWHM of ~35 km s-1, somewhat dependent on the assumed line shape. We analyze the line shape in the context of three different radial outflow models for which we provide analytical expressions. We also detected a weaker 557 GHz emission line from W Hydrae. We find that these and other H2O emission-line strengths scale as suggested by Zubko and Elitzur.

Optimal Bandwidth Selection in Observed-Score Kernel Equating

Science.gov (United States)

Häggström, Jenny; Wiberg, Marie

2014-01-01

The selection of bandwidth in kernel equating is important because it has a direct impact on the equated test scores. The aim of this article is to examine the use of double smoothing when selecting bandwidths in kernel equating and to compare double smoothing with the commonly used penalty method. This comparison was made using both an equivalent…

24-GHz LTCC Fractal Antenna Array SoP With Integrated Fresnel Lens

KAUST Repository

Ghaffar, Farhan A.

2012-09-30

A novel 24-GHz mixed low-temperature co-fired ceramic (LTCC) tape based system-on-package (SoP) is presented, which incorporates a fractal antenna array with an integrated grooved Fresnel lens. The four-element fractal array employs a relatively low dielectric constant substrate (CT707, εr = 6.4), whereas the lens has been realized on a high-dielectric-constant superstrate (CT765, εr = 68.7 ). The two (substrate and superstrate) are integrated through four corner posts to realize the required air gap (focal distance). The fractal array alone provides a measured gain of 8.9 dBi. Simulations predict that integration of this array with the lens increases the gain by 6 dB. Measurements reveal that the design is susceptible to LTCC fabrication tolerances. In addition to high gain, the SoP provides a bandwidth of 8%. The high performance and compact size (24 × 24 × 4.8 mm3 ) of the design makes it highly suitable for emerging wireless applications such as automotive radar front end.

Millimeter- and submillimeter-wave surveys of Orion A emission lines in the ranges 200.7-202.3, 203.7-205.3, and 330-360 GHz

International Nuclear Information System (INIS)

Jewell, P.R.; Hollis, J.M.; Lovas, F.J.; Snyder, L.E.

1989-01-01

A continuous spectral line survey of the Orion A position from 330.5 to 360.1 GHz was carried out. This survey covers nearly the entire 870 micron atmospheric window accessible from ground-based observations. Approximately 160 distinct spectral features composed of about 180 lines were detected, 29 of which could not be readily identified. In addition, Orion A from 200.7 to 202.3 GHz and from 203.7 to 205.3 GHz and 42 distinct new spectral lines were detected, including four that are unidentified at present. These data sets are the first thorough survey results in these spectral regions. The new interstellar lines in the survey bands are tabulated and displayed graphically. Moreover, the data are being made available to the Astronomical Data Center at the Goddard Space Flight Center for distribution by request to the astronomical community. 14 refs

A Compact QPSK Modulator with Low Amplitude and Phase Imbalance for Remote Sensing Applications

KAUST Repository

Ghaffar, Farhan Abdul

2012-09-30

A new, compact and wide-band Quadrature Phase Shift Keying (QPSK) modulator is presented for remote sensing applications. The microstrip-based modulator employs quadrature hybrid coupler, Wilkinson divider, rat race coupler and GaAs MESFET switches. It is designed to be part of an X band remote sensing transmitter with a center frequency of 8.25GHz. The fabricated module demonstrates the lowest reported amplitude and phase imbalances (0.1dB and 0.4° respectively) around its center frequency. The modulation, tested up to 160 Mbps data rate, displays carrier suppression greater than 30 dB. With negligible DC power consumption and low insertion loss, it operates for a wide bandwidth of 3 GHz (7-10 GHz). The effect of amplitude and phase imbalance is investigated on the performance of the modulator. Finally, a transmitter employing this modulator exhibits an excellent overall Error Vector Magnitude (EVM) of around 8 % that is considerably low as compared to the typically obtained values for such transmitters.

A Compact QPSK Modulator with Low Amplitude and Phase Imbalance for Remote Sensing Applications

KAUST Repository

Ghaffar, Farhan Abdul; Al-Naffouri, Tareq Y.; Mobeen, M. Kashan; Salama, Khaled N.; Shamim, Atif

2012-01-01

A new, compact and wide-band Quadrature Phase Shift Keying (QPSK) modulator is presented for remote sensing applications. The microstrip-based modulator employs quadrature hybrid coupler, Wilkinson divider, rat race coupler and GaAs MESFET switches. It is designed to be part of an X band remote sensing transmitter with a center frequency of 8.25GHz. The fabricated module demonstrates the lowest reported amplitude and phase imbalances (0.1dB and 0.4° respectively) around its center frequency. The modulation, tested up to 160 Mbps data rate, displays carrier suppression greater than 30 dB. With negligible DC power consumption and low insertion loss, it operates for a wide bandwidth of 3 GHz (7-10 GHz). The effect of amplitude and phase imbalance is investigated on the performance of the modulator. Finally, a transmitter employing this modulator exhibits an excellent overall Error Vector Magnitude (EVM) of around 8 % that is considerably low as compared to the typically obtained values for such transmitters.

A Hybrid OFDM-TDM Architecture with Decentralized Dynamic Bandwidth Allocation for PONs

Directory of Open Access Journals (Sweden)

Taner Cevik

2013-01-01

Full Text Available One of the major challenges of passive optical networks is to achieve a fair arbitration mechanism that will prevent possible collisions from occurring at the upstream channel when multiple users attempt to access the common fiber at the same time. Therefore, in this study we mainly focus on fair bandwidth allocation among users, and present a hybrid Orthogonal Frequency Division Multiplexed/Time Division Multiplexed architecture with a dynamic bandwidth allocation scheme that provides satisfying service qualities to the users depending on their varying bandwidth requirements. Unnecessary delays in centralized schemes occurring during bandwidth assignment stage are eliminated by utilizing a decentralized approach. Instead of sending bandwidth demands to the optical line terminal (OLT which is the only competent authority, each optical network unit (ONU runs the same bandwidth demand determination algorithm. ONUs inform each other via signaling channel about the status of their queues. This information is fed to the bandwidth determination algorithm which is run by each ONU in a distributed manner. Furthermore, Light Load Penalty, which is a phenomenon in optical communications, is mitigated by limiting the amount of bandwidth that an ONU can demand.

A Hybrid OFDM-TDM Architecture with Decentralized Dynamic Bandwidth Allocation for PONs

Science.gov (United States)

Cevik, Taner

2013-01-01

One of the major challenges of passive optical networks is to achieve a fair arbitration mechanism that will prevent possible collisions from occurring at the upstream channel when multiple users attempt to access the common fiber at the same time. Therefore, in this study we mainly focus on fair bandwidth allocation among users, and present a hybrid Orthogonal Frequency Division Multiplexed/Time Division Multiplexed architecture with a dynamic bandwidth allocation scheme that provides satisfying service qualities to the users depending on their varying bandwidth requirements. Unnecessary delays in centralized schemes occurring during bandwidth assignment stage are eliminated by utilizing a decentralized approach. Instead of sending bandwidth demands to the optical line terminal (OLT) which is the only competent authority, each optical network unit (ONU) runs the same bandwidth demand determination algorithm. ONUs inform each other via signaling channel about the status of their queues. This information is fed to the bandwidth determination algorithm which is run by each ONU in a distributed manner. Furthermore, Light Load Penalty, which is a phenomenon in optical communications, is mitigated by limiting the amount of bandwidth that an ONU can demand. PMID:24194684

Design of a broadband passive X-band double-balanced mixer in SiGe HBT technology

DEFF Research Database (Denmark)

Michaelsen, Rasmus Schandorph; Johansen, Tom Keinicke; Tamborg, Kjeld M.

2014-01-01

) and the radio frequency (RF) port. A break out of the Marchand balun is measured. This demonstrates good phase and magnitude match of 0.7° and 0.11 dB, respectively. The Marchand baluns are broadband with a measured 3 dB bandwidth of 6.4 GHz, while still having a magnitude imbalance better than 0.4 d...... frequency of 8.5 GHz is −9.8 dB at an LO drive level of 15 dBm. The whole mixer is very broadband with 3 dB bandwidth from 7 to 12 GHz covering the entire X-band. The LO–IF, RF–IF, and RF–LO isolation is better than 46, 36, and 36 dB, respectively, in the entire band of operation.......B and a phase imbalance better than 5°. Unfortunately with a rather high loss of 2.5 dB, mainly due to the low Q-factor of the inductors used. The mixer is optimized for use in doppler radars and is highly linear with a 1 dB compression point above 12 dBm IIP2 of 66 dBm. The conversion gain at the center...

Bandwidth Estimation in Wireless Lans for Multimedia Streaming Services

Directory of Open Access Journals (Sweden)

Heung Ki Lee

2007-01-01

Full Text Available The popularity of multimedia streaming services via wireless networks presents major challenges in the management of network bandwidth. One challenge is to quickly and precisely estimate the available bandwidth for the decision of streaming rates of layered and scalable multimedia services. Previous studies based on wired networks are too burdensome to be applied to multimedia applications in wireless networks. In this paper, a new method, IdleGap, is suggested to estimate the available bandwidth of a wireless LAN based on the information from a low layer in the protocol stack. We use a network simulation tool, NS-2, to evaluate our new method with various ranges of cross-traffic and observation times. Our simulation results show that IdleGap accurately estimates the available bandwidth for all ranges of cross-traffic (100 Kbps ∼ 1 Mbps with a very short observation time of 10 seconds.

Bandwidth allocation and pricing problem for a duopoly market

Directory of Open Access Journals (Sweden)

You Peng-Sheng

2011-01-01

Full Text Available This research discusses the Internet service provider (ISP bandwidth allocation and pricing problems for a duopoly bandwidth market with two competitive ISPs. According to the contracts between Internet subscribers and ISPs, Internet subscribers can enjoy their services up to their contracted bandwidth limits. However, in reality, many subscribers may experience the facts that their on-line requests are denied or their connection speeds are far below their contracted speed limits. One of the reasons is that ISPs accept too many subscribers as their subscribers. To avoid this problem, ISPs can set limits for their subscribers to enhance their service qualities. This paper develops constrained nonlinear programming to deal with this problem for two competitive ISPs. The condition for reaching the equilibrium between the two competitive firms is derived. The market equilibrium price and bandwidth resource allocations are derived as closed form solutions.

Efficient Bandwidth Management for Ethernet Passive Optical Networks

KAUST Repository

Elrasad, Amr Elsayed M.

2016-05-15

The increasing bandwidth demands in access networks motivates network operators, networking devices manufacturers, and standardization institutions to search for new approaches for access networks. These approaches should support higher bandwidth, longer distance between end user and network operator, and less energy consumption. Ethernet Passive Optical Network (EPON) is a favorable choice for broadband access networks. EPONs support transmission rates up to 10 Gbps. EPONs also support distance between end users and central office up to 20 Km. Moreover, optical networks have the least energy consumption among all types of networks. In this dissertation, we focus on reducing delay and saving energy in EPONs. Reducing delay is essential for delay-sensitive traffic, while minimizing energy consumption is an environmental necessity and also reduces the network operating costs. We identify five challenges, namely excess bandwidth allocation, frame delineation, congestion resolution, large round trip time delay in long-reach EPONs (LR-EPONs), and energy saving. We provide a Dynamic Bandwidth Allocation (DBA) approach for each challenge. We also propose a novel scheme that combines the features of the proposed approaches in one highly performing scheme. Our approach is to design novel DBA protocols that can further reduce the delay and be simultaneously simple and fair. We also present a dynamic bandwidth allocation scheme for Green EPONs taking into consideration maximizing energy saving under target delay constraints. Regarding excess bandwidth allocation, we develop an effective DBA scheme called Delayed Excess Scheduling (DES). DES achieves significant delay and jitter reduction and is more suitable for industrial deployment due to its simplicity. Utilizing DES in hybrid TDM/WDM EPONs (TWDM-EPONs) is also investigated. We also study eliminating the wasted bandwidth due to frame delineation. We develop an interactive DBA scheme, Efficient Grant Sizing Interleaved

Correlation and image compression for limited-bandwidth CCD.

Energy Technology Data Exchange (ETDEWEB)

Thompson, Douglas G.

2005-07-01

As radars move to Unmanned Aerial Vehicles with limited-bandwidth data downlinks, the amount of data stored and transmitted with each image becomes more significant. This document gives the results of a study to determine the effect of lossy compression in the image magnitude and phase on Coherent Change Detection (CCD). We examine 44 lossy compression types, plus lossless zlib compression, and test each compression method with over 600 CCD image pairs. We also derive theoretical predictions for the correlation for most of these compression schemes, which compare favorably with the experimental results. We recommend image transmission formats for limited-bandwidth programs having various requirements for CCD, including programs which cannot allow performance degradation and those which have stricter bandwidth requirements at the expense of CCD performance.

Large-bandwidth planar photonic crystal waveguides

DEFF Research Database (Denmark)

Søndergaard, Thomas; Lavrinenko, Andrei

2002-01-01

A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

Time-resolved x-ray diagnostics

International Nuclear Information System (INIS)

Lyons, P.B.

1981-01-01

Techniques for time-resolved x-ray diagnostics will be reviewed with emphasis on systems utilizing x-ray diodes or scintillators. System design concerns for high-bandwidth (> 1 GHz) diagnostics will be emphasized. The limitations of a coaxial cable system and a technique for equalizing to improve bandwidth of such a system will be reviewed. Characteristics of new multi-GHz amplifiers will be presented. An example of a complete operational system on the Los Alamos Helios laser will be presented which has a bandwidth near 3 GHz over 38 m of coax. The system includes the cable, an amplifier, an oscilloscope, and a digital camera readout

Bandwidth extension of speech using perceptual criteria

CERN Document Server

Berisha, Visar; Liss, Julie

2013-01-01

Bandwidth extension of speech is used in the International Telecommunication Union G.729.1 standard in which the narrowband bitstream is combined with quantized high-band parameters. Although this system produces high-quality wideband speech, the additional bits used to represent the high band can be further reduced. In addition to the algorithm used in the G.729.1 standard, bandwidth extension methods based on spectrum prediction have also been proposed. Although these algorithms do not require additional bits, they perform poorly when the correlation between the low and the high band is weak. In this book, two wideband speech coding algorithms that rely on bandwidth extension are developed. The algorithms operate as wrappers around existing narrowband compression schemes. More specifically, in these algorithms, the low band is encoded using an existing toll-quality narrowband system, whereas the high band is generated using the proposed extension techniques. The first method relies only on transmitted high-...

Reliable IoT Storage: Minimizing Bandwidth Use in Storage Without Newcomer Nodes

DEFF Research Database (Denmark)

Zhao, Xiaobo; Lucani Rötter, Daniel Enrique; Shen, Xiaohong

2018-01-01

This letter characterizes the optimal policies for bandwidth use and storage for the problem of distributed storage in Internet of Things (IoT) scenarios, where lost nodes cannot be replaced by new nodes as is typically assumed in Data Center and Cloud scenarios. We develop an information flow...... model that captures the overall process of data transmission between IoT devices, from the initial preparation stage (generating redundancy from the original data) to the different repair stages with fewer and fewer devices. Our numerical results show that in a system with 10 nodes, the proposed optimal...

THE ZEEMAN EFFECT IN THE 44 GHZ CLASS I METHANOL MASER LINE TOWARD DR21(OH)

Energy Technology Data Exchange (ETDEWEB)

Momjian, E. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Sarma, A. P., E-mail: emomjian@nrao.edu, E-mail: asarma@depaul.edu [Physics Department, DePaul University, 2219 N. Kenmore Avenue, Byrne Hall 211, Chicago, IL 60614 (United States)

2017-01-10

We report detection of the Zeeman effect in the 44 GHz Class I methanol maser line, toward the star-forming region DR21(OH). In a 219 Jy beam{sup −1} maser centered at an LSR velocity of 0.83 km s{sup −1}, we find a 20- σ detection of zB {sub los} = 53.5 ± 2.7 Hz. If 44 GHz methanol masers are excited at n ∼ 10{sup 7–8} cm{sup −3}, then the B versus n {sup 1/2} relation would imply, from comparison with Zeeman effect detections in the CN(1 − 0) line toward DR21(OH), that magnetic fields traced by 44 GHz methanol masers in DR21(OH) should be ∼10 mG. Combined with our detected zB {sub los} = 53.5 Hz, this would imply that the value of the 44 GHz methanol Zeeman splitting factor z is ∼5 Hz mG{sup −1}. Such small values of z would not be a surprise, as the methanol molecule is non-paramagnetic, like H{sub 2}O. Empirical attempts to determine z , as demonstrated, are important because there currently are no laboratory measurements or theoretically calculated values of z for the 44 GHz CH{sub 3}OH transition. Data from observations of a larger number of sources are needed to make such empirical determinations robust.

A compact dual band MIMO PIFA for 5G applications

Science.gov (United States)

Rachakonda, A.; Bang, P.; Mudiganti, J.

2017-11-01

5G applications support operations in 28, 37, 60 and 73GHz bands and is expected to support 1GHz bandwidth. In the present paper, planar inverted F antenna for 28GHz operation has been proposed for 5G applications for which a return loss of -17.46dB and a gain of 9.30dB have been observed. In addition, the design has been extended for dual band operation at 28 and 37GHz by implementing an L slot in the patch. An excellent return loss of -32.54dB and -18.57dB with a gain of 8.62dB has been observed. Moreover, a feasible bandwidth of 1.02GHz has been obtained in former design, while an enhanced bandwidth of 1.3GHz has been obtained at both bands in case of latter design. However, for better gain & data rate considerations, the previous design has been extended as a MIMO configuration with 2 antenna elements (2x1) and corresponding performance parameters have been evaluated.

Variable Bandwidth Analog Channel Filters for Software Defined Radio

NARCIS (Netherlands)

Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

2001-01-01

An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper first explains the importance of channel filtering. Then the advantage of analog channel filtering with a variable bandwidth in a Software Defined Radio is

Multichroic Antenna-Coupled Bolometers for CMB Polarization and Sub-mm Observations

Science.gov (United States)

Lee, Adrian

We propose to develop planar antenna-coupled superconducting bolometer arrays for observations at sub-millimeter to millimeter wavelengths. Our pixel architecture features a dual-polarization log-periodic antenna with a 4:1-bandwidth ratio, followed by a filter bank that divides the total bandwidth into several broad photometric bands. The advantages of this approach, compared with those using conventional single-color pixels, include a combination of greatly reduced focal-plane mass, higher array sensitivity, and a larger number of spectral bands. These advantages have the potential to greatly reduce the cost and/or increase the performance of NASA missions in the sub-millimeter to millimeter bands. For CMB polarization measurements, a wide frequency range of roughly 30 to 300 GHz is required to subtract galactic foregrounds. The multichroic architecture we propose enables a relatively low-cost 30-cm aperture space mission to have sufficient sensitivity to probe below the tensor-to-scalar ratio r = 0.01. For a larger aperture mission, such as the EPIC-IM concept, the proposed technology could reduce the focal-plane mass by a factor of 2-3, with great savings in required cryocooler performance and therefore cost. We have demonstrated the lens-coupled antenna concept in the POLARBEAR ground-based CMB polarization experiment now operating in Chile. That experiment uses a single-band planar antenna and produces excellent beam properties and optical efficiency. In the laboratory, we have measured two octaves of total bandwidth in the log-periodic sinuous antenna. We have built filter banks of 2, 3, and 7 bands with 4, 6, and 14 bolometers per pixel for two linear polarizations. Building on these accomplishments, the deliverables for the proposed work include: *Two pixel types that together cover the range from 30 to 300 GHz. The low-frequency pixel will have bands centered at 35, 50, and 80 GHz and the high frequency pixel will have bands centered at 120, 180, and 270

Data analysis-based autonomic bandwidth adjustment in software defined multi-vendor optical transport networks.

Science.gov (United States)

Li, Yajie; Zhao, Yongli; Zhang, Jie; Yu, Xiaosong; Jing, Ruiquan

2017-11-27

Network operators generally provide dedicated lightpaths for customers to meet the demand for high-quality transmission. Considering the variation of traffic load, customers usually rent peak bandwidth that exceeds the practical average traffic requirement. In this case, bandwidth provisioning is unmetered and customers have to pay according to peak bandwidth. Supposing that network operators could keep track of traffic load and allocate bandwidth dynamically, bandwidth can be provided as a metered service and customers would pay for the bandwidth that they actually use. To achieve cost-effective bandwidth provisioning, this paper proposes an autonomic bandwidth adjustment scheme based on data analysis of traffic load. The scheme is implemented in a software defined networking (SDN) controller and is demonstrated in the field trial of multi-vendor optical transport networks. The field trial shows that the proposed scheme can track traffic load and realize autonomic bandwidth adjustment. In addition, a simulation experiment is conducted to evaluate the performance of the proposed scheme. We also investigate the impact of different parameters on autonomic bandwidth adjustment. Simulation results show that the step size and adjustment period have significant influences on bandwidth savings and packet loss. A small value of step size and adjustment period can bring more benefits by tracking traffic variation with high accuracy. For network operators, the scheme can serve as technical support of realizing bandwidth as metered service in the future.

The effect of concurrent bandwidth feedback on learning the lane-keeping task in a driving simulator.

Science.gov (United States)

de Groot, Stefan; de Winter, Joost C F; López García, José Manuel; Mulder, Max; Wieringa, Peter A

2011-02-01

The aim of this study was to investigate whether concurrent bandwidth feedback improves learning of the lane-keeping task in a driving simulator. Previous research suggests that bandwidth feedback improves learning and that off-target feedback is superior to on-target feedback. This study aimed to extend these findings for the lane-keeping task. Participants without a driver's license drove five 8-min lane-keeping sessions in a driver training simulator: three practice sessions, an immediate retention session, and a delayed retention session I day later. There were four experimental groups (n=15 per group): (a) on-target, receiving seat vibrations when the center of the car was within 0.5 m of the lane center; (b) off-target, receiving seat vibrations when the center of the car was more than 0.5 m away from the lane center; (c) control, receiving no vibrations; and (d) realistic, receiving seat vibrations depending on engine speed. During retention, all groups were provided with the realistic vibrations. During practice, on-target and off-target groups had better lane-keeping performance than the nonaugmented groups, but this difference diminished in the retention phase. Furthermore, during late practice and retention, the off-target group outperformed the on-target group.The off-target group had a higher rate of steering reversal and higher steering entropy than the nonaugmented groups, whereas no clear group differences were found regarding mean speed, mental workload, or self-reported measures. Off-target feedback is superior to on-target feedback for learning the lane-keeping task. This research provides knowledge to researchers and designers of training systems about the value of feedback in simulator-based training of vehicular control.

3600 digital phase detector with 100-kHz bandwidth

International Nuclear Information System (INIS)

Reid, D.W.; Riggin, D.; Fazio, M.V.; Biddle, R.S.; Patton, R.D.; Jackson, H.A.

1981-01-01

The general availability of digital circuit components with propagation delay times of a few nanoseconds makes a digital phase detector with good bandwidth feasible. Such a circuit has a distinct advantage over its analog counterpart because of its linearity over wide range of phase shift. A phase detector that is being built at Los Alamos National Laboratory for the Fusion Materials Irradiation Test (FMIT) project is described. The specifications are 100-kHz bandwidth, linearity of +- 1 0 over +- 180 0 of phase shift, and 0.66 0 resolution. To date, the circuit has achieved the bandwidth and resolution. The linearity is approximately +- 3 0 over +- 180 0 phase shift

Bandwidth auction for SVC streaming in dynamic multi-overlay

Science.gov (United States)

Xiong, Yanting; Zou, Junni; Xiong, Hongkai

2010-07-01

In this paper, we study the optimal bandwidth allocation for scalable video coding (SVC) streaming in multiple overlays. We model the whole bandwidth request and distribution process as a set of decentralized auction games between the competing peers. For the upstream peer, a bandwidth allocation mechanism is introduced to maximize the aggregate revenue. For the downstream peer, a dynamic bidding strategy is proposed. It achieves maximum utility and efficient resource usage by collaborating with a content-aware layer dropping/adding strategy. Also, the convergence of the proposed auction games is theoretically proved. Experimental results show that the auction strategies can adapt to dynamic join of competing peers and video layers.

Towards Bandwidth Scalable Transceiver Technology for Optical Metro-Access Networks

DEFF Research Database (Denmark)

Spolitis, Sandis; Bobrovs, Vjaceslavs; Wagner, Christoph

2015-01-01

sliceable transceiver for 1 Gbit/s non-return to zero (NRZ) signal sliced into two slices is presented. Digital signal processing (DSP) power consumption and latency values for proposed sliceable transceiver technique are also discussed. In this research post FEC with 7% overhead error free transmission has......Massive fiber-to-the-home network deployment is creating a challenge for telecommunications network operators: exponential increase of the power consumption at the central offices and a never ending quest for equipment upgrades operating at higher bandwidth. In this paper, we report on flexible...... signal slicing technique, which allows transmission of high-bandwidth signals via low bandwidth electrical and optoelectrical equipment. The presented signal slicing technique is highly scalable in terms of bandwidth which is determined by the number of slices used. In this paper performance of scalable...

On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

Science.gov (United States)

Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

2017-02-01

Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

Bandwidth tunable microwave photonic filter based on digital and analog modulation

Science.gov (United States)

Zhang, Qi; Zhang, Jie; Li, Qiang; Wang, Yubing; Sun, Xian; Dong, Wei; Zhang, Xindong

2018-05-01

A bandwidth tunable microwave photonic filter based on digital and analog modulation is proposed and experimentally demonstrated. The digital modulation is used to broaden the effective gain spectrum and the analog modulation is to get optical lines. By changing the symbol rate of data pattern, the bandwidth is tunable from 50 MHz to 700 MHz. The interval of optical lines is set according to the bandwidth of gain spectrum which is related to the symbol rate. Several times of bandwidth increase are achieved compared to a single analog modulation and the selectivity of the response is increased by 3.7 dB compared to a single digital modulation.

60 Gbit/s 400 GHz Wireless Transmission

DEFF Research Database (Denmark)

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...

Ultra-high bandwidth quantum secured data transmission

Science.gov (United States)

Dynes, James F.; Tam, Winci W.-S.; Plews, Alan; Fröhlich, Bernd; Sharpe, Andrew W.; Lucamarini, Marco; Yuan, Zhiliang; Radig, Christian; Straw, Andrew; Edwards, Tim; Shields, Andrew J.

2016-10-01

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.

A Compact Narrow-Band Bandstop Filter Using Spiral-Shaped Defected Microstrip Structure

Directory of Open Access Journals (Sweden)

J. Wang

2014-04-01

Full Text Available A novel compact narrow-band bandstop filter is implemented by using the proposed spiral-shaped defected microstrip structure (SDMS in this paper. Compared with other DMSs, the presented SDMS exhibits the advantage of compact size and narrow stopband. Meanwhile, an approximate design rule of the SDMS is achieved and the effects of the dimensions on the resonant frequency and 3 dB fractional bandwidth (FBW are analyzed in detail. Both the simulation and measurement results of the fabricated bandstop filter show that it has a 10 dB stopband from 3.4 GHz to 3.6 GHz with more than 45 dB rejection at the center frequency.

A wideband superconducting filter at Ku-band based on interdigital coupling

Science.gov (United States)

Jiang, Ying; Wei, Bin; Cao, Bisong; Li, Qirong; Guo, Xubo; Jiang, Linan; Song, Xiaoke; Wang, Xiang

2018-04-01

In this paper, an interdigital-type resonator with strong electric coupling is proposed for the wideband high-frequency (>10 GHz) filter design. The proposed microstrip resonator consists of an H-shaped main line part with its both ends installed with interdigital finger parts. Strong electric coupling is achieved between adjacent resonators. A six-pole high-temperature superconducting filter at Ku-band using this resonator is designed and fabricated. The filter has a center frequency of 15.11 GHz with a fractional bandwidth of 30%. The insertion loss of the passband is less than 0.3 dB, and the return loss is greater than 14 dB without any tuning.

Path connectivity based spectral defragmentation in flexible bandwidth networks.

Science.gov (United States)

Wang, Ying; Zhang, Jie; Zhao, Yongli; Zhang, Jiawei; Zhao, Jie; Wang, Xinbo; Gu, Wanyi

2013-01-28

Optical networks with flexible bandwidth provisioning have become a very promising networking architecture. It enables efficient resource utilization and supports heterogeneous bandwidth demands. In this paper, two novel spectrum defragmentation approaches, i.e. Maximum Path Connectivity (MPC) algorithm and Path Connectivity Triggering (PCT) algorithm, are proposed based on the notion of Path Connectivity, which is defined to represent the maximum variation of node switching ability along the path in flexible bandwidth networks. A cost-performance-ratio based profitability model is given to denote the prons and cons of spectrum defragmentation. We compare these two proposed algorithms with non-defragmentation algorithm in terms of blocking probability. Then we analyze the differences of defragmentation profitability between MPC and PCT algorithms.

Dual Wideband Antenna for WLAN/WiMAX and Satellite System Applications Based on a Metamaterial Transmission Line

International Nuclear Information System (INIS)

Jin Da-Lin; Hong Jing-Song; Xiong Han

2012-01-01

A dual band planar antenna based on metamaterial transmission lines is presented for WLAN, WiMAX, and satellite system communication applications. This antenna is composed of an interdigital capacitor and a ground plane with triangular shaped slots on its top edges to broaden the impedance bandwidth. The measured bandwidth for 10 dB return loss is from 3.29 to 4.27 GHz and 5.04 to 9.8 GHz, covering the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX bands, and the X-band satellite communication systems at 7.4 GHz. The proposed antenna exhibits stable monopole-like radiation patterns and enough gains across the dual operating bands

Effect of thickness on microwave absorptive behavior of La-Na doped Co-Zr barium hexaferrites in 18.0–26.5 GHz band

Energy Technology Data Exchange (ETDEWEB)

Arora, Amit [D.A.V. Institute of Engineering and Technology, Jalandhar (India); Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Pubby, Kunal [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India)

2017-02-01

In this research, the microwave properties of Lanthanum-Sodium doped Cobalt-Zirconium barium hexaferrites, intended as microwave absorbers, are analyzed on Vector Network Analyzer in K-band. The results indicate that the doping has resulted in lowering of real permittivity and enhancement of dielectric losses. Real permeability has shown increase while magnetic losses have shown decrease in value with doping. All these four properties have shown very small variation with frequency in the scanned frequency range which indicates the relaxation type of behavior. Microwave absorption characteristics of these compositions are analyzed with change in sample thickness. The results demonstrate that the matching frequency of the microwave absorber shifts towards lower side of frequency band with increase in thickness. The complete analysis of the prepared microwave absorbers shows a striking achievement with very low reflection loss and wide absorption bandwidth for all the six compositions in 18–26.5 GHz frequency band. - Highlights: • Electromagnetic Characterization of M-hexaferrites in K-band (18–26.5 GHz) • Variation of absorption properties with thickness of sample. • Satisfaction of quarter-wavelength condition for absorption properties • Results of double-layer absorbers (not reports till day by anyone).

Dual Polarized Monopole Patch Antennas for UWB Applications with Elimination of WLAN Signals

Directory of Open Access Journals (Sweden)

P. Kumar

2016-05-01

Full Text Available This paper presents the design, fabrication and measurement of dual polarized microstrip patch antennas for ultra wideband (UWB applications with notch at 5-6 GHz band. The proposed antenna rejects the wireless local area network (WLAN signals and work properly in the entire remaining ultra-wideband. Two antennas are designed for two different frequency bands of ultra wideband and both antennas together produce the entire ultra wideband with notch at 5-6 GHz band. The antennas are fed by a 50 coaxial probe and the entire design is optimized using CST Microwave Studio. The bandwidth of 3.1-5 GHz is achieved by the optimized design of Antenna-1 and the bandwidth of 6 -10.6 GHz is achieved by the optimized design of Antenna-2. The bandwidth of the optimized combined antenna is 3.1-10.6 GHz with elimination of the 5-6 GHz band. Both antennas are simulated, developed and measured. The simulated and measured results are presented. The two designed dual polarized antennas i.e. Antenna-1 and Antenna-2 can be used for 3.1-5 GHz band and 6-10.6 GHz band dual polarized applications, respectively, and the combined antenna structure can be used for UWB dual polarized applications with elimination of 5-6 GHz band signals.

41 GHz and 10.6 GHz low threshold and low noise InAs/InP quantum dash two-section mode-locked lasers in L band

DEFF Research Database (Denmark)

Dontabactouny, M.; Piron, R.; Klaime, K.

2012-01-01

This paper reports recent results on InAs/InP quantum dash-based, two-section, passively mode-locked lasers pulsing at 41 GHz and 10.6 GHz and emitting at 1.59 mu m at 20 degrees C. The 41-GHz device (1 mm long) starts lasing at 25 mA under uniform injection and the 10.6 GHz (4 mm long) at 71 m...

Optical Multidimensional Switching for Data Center Networks

OpenAIRE

Kamchevska, Valerija; Galili, Michael; Oxenløwe, Leif Katsuo; Berger, Michael Stübert

2017-01-01

Optical switches are known for the ability to provide high bandwidth connectivity at a relatively low power consumption and low latency. Several recent demonstrations on optical data center architectures confirm the potential for introducing all-optical switching within the data center, thus avoiding power hungry optical-electrical-optical conversions at each node. This Ph.D. thesis focuses precisely on the application of optical technologies in data center networks where optics is not only u...

Bandwidth-narrowed Bragg gratings inscribed in double-cladding fiber by femtosecond laser.

Science.gov (United States)

Shi, Jiawei; Li, Yuhua; Liu, Shuhui; Wang, Haiyan; Liu, Ningliang; Lu, Peixiang

2011-01-31

Bragg gratings with the bandwidth(FWHM) narrowed up to 79 pm were inscribed in double-cladding fiber with femtosecond radiation and a phase mask followed by an annealing treatment. With the annealing temperature below a critical value, the bandwidth of Bragg gratings induced by Type I-IR and Type II-IR index change was narrowed without the reduction of reflectivity. The bandwidth narrowing is due to the profile transformation of the refractive index modulation caused by the annealing treatment. This mechanism was verified by comparing bandwidth narrowing processes of FBGs written with different power densities.

Review of high bandwidth fiber optics radiation sensors

International Nuclear Information System (INIS)

Lyons, P.B.

1985-01-01

This paper summarizes the use of fiber optics or guided optical systems for radiation sensors. It is limited a passive systems wherein electrical is not required at the sensor location. However, electrically powered light sources, receivers and/or recorders may still be required for detection and data storage in sensor system operation. This paper emphasizes sensor technologies that permit high bandwidth measurements of transient radiation levels, and will also discuss several low bandwidth applications. 60 refs

MPTCP Tunnel: An Architecture for Aggregating Bandwidth of Heterogeneous Access Networks

Directory of Open Access Journals (Sweden)

Xiaolan Liu

2018-01-01

Full Text Available Fixed and cellular networks are two typical access networks provided by operators. Fixed access network is widely employed; nevertheless, its bandwidth is sometimes not sufficient enough to meet user bandwidth requirements. Meanwhile, cellular access network owns unique advantages of wider coverage, faster increasing link speed, more flexible deployment, and so forth. Therefore, it is attractive for operators to mitigate the bandwidth shortage by bundling these two. Actually, there have been existing schemes proposed to aggregate the bandwidth of two access networks, whereas they all have their own problems, like packet reordering or extra latency overhead. To address this problem, we design new architecture, MPTCP Tunnel, to aggregate the bandwidth of multiple heterogeneous access networks from the perspective of operators. MPTCP Tunnel uses MPTCP, which solves the reordering problem essentially, to bundle multiple access networks. Besides, MPTCP Tunnel sets up only one MPTCP connection at play which adapts itself to multiple traffic types and TCP flows. Furthermore, MPTCP Tunnel forwards intact IP packets through access networks, maintaining the end-to-end TCP semantics. Experimental results manifest that MPTCP Tunnel can efficiently aggregate the bandwidth of multiple access networks and is more adaptable to the increasing heterogeneity of access networks than existing mechanisms.

An Application-Level QoS Control Method Based on Local Bandwidth Scheduling

Directory of Open Access Journals (Sweden)

Yong Wang

2018-01-01

Full Text Available Quality of service (QoS is an important performance indicator for Web applications and bandwidth is a key factor affecting QoS. Current methods use network protocols or ports to schedule bandwidth, which require tedious manual configurations or modifications of the underlying network. Some applications use dynamic ports and the traditional port-based bandwidth control methods cannot deal with them. A new QoS control method based on local bandwidth scheduling is proposed, which can schedule bandwidth at application level in a user-transparent way and it does not require tedious manual configurations. Experimental results indicate that the new method can effectively improve the QoS for applications, and it can be easily integrated into current Web applications without the need to modify the underlying network.

Photon-counting 1.0 GHz-phase-modulation fluorometer

International Nuclear Information System (INIS)

Mizuno, T.; Nakao, S.; Mizutani, Y.; Iwata, T.

2015-01-01

We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method

Photon-counting 1.0 GHz-phase-modulation fluorometer

Energy Technology Data Exchange (ETDEWEB)

Mizuno, T.; Nakao, S.; Mizutani, Y.; Iwata, T., E-mail: iwata@tokushima-u.ac.jp [Division of Energy System, Institute of Technology and Science, Tokushima University, 2-1 Minami-Jyosanjima, Tokushima 770-8506 (Japan)

2015-04-15

We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

Development of a bandwidth limiting neutron chopper for CSNS

Science.gov (United States)

Wang, P.; Yang, B.; Cai, W. L.

2015-08-01

Bandwidth limiting neutron choppers are indispensable key equipments for the time-of-flight neutron scattering spectrometers of China Spallation Neutron Source (CSNS). The main principle is to chop the neutron beam to limit the neutron wavelength bandwidth at the neutron detector. We have successfully developed a bandwidth limiting neutron chopper for CSNS in the CSNS advance research project II. The transmission rate of the neutron absorbing coating is less than 1×10-4 (for 1 angstrom neutron). The phase control accuracy is ±0.084° (±9.4 μs at 25 Hz). The dynamic balance grade is G1.0. Various experimental technical features have met the design requirements, and it also runs stably and reliably during the long-term tests.

Development of a bandwidth limiting neutron chopper for CSNS

International Nuclear Information System (INIS)

Wang, P.; Yang, B.; Cai, W.L.

2015-01-01

Bandwidth limiting neutron choppers are indispensable key equipments for the time-of-flight neutron scattering spectrometers of China Spallation Neutron Source (CSNS). The main principle is to chop the neutron beam to limit the neutron wavelength bandwidth at the neutron detector. We have successfully developed a bandwidth limiting neutron chopper for CSNS in the CSNS advance research project II. The transmission rate of the neutron absorbing coating is less than 1×10 −4 (for 1 angstrom neutron). The phase control accuracy is ±0.084° (±9.4 μs at 25 Hz). The dynamic balance grade is G1.0. Various experimental technical features have met the design requirements, and it also runs stably and reliably during the long-term tests

Graphene photodetectors with a bandwidth  >76 GHz fabricated in a 6″ wafer process line

Science.gov (United States)

Schall, Daniel; Porschatis, Caroline; Otto, Martin; Neumaier, Daniel

2017-03-01

In recent years, the data traffic has grown exponentially and the forecasts indicate a huge market that could be addressed by communication infrastructure and service providers. However, the processing capacity, space, and energy consumption of the available technology is a serious bottleneck for the exploitation of these markets. Chip-integrated optical communication systems hold the promise of significantly improving these issues related to the current technology. At the moment, the answer to the question which material is best suited for ultrafast chip integrated communication systems is still open. In this manuscript we report on ultrafast graphene photodetectors with a bandwidth of more than 76 GHz well suitable for communication links faster than 100 GBit s-1 per channel. We extract an upper value of 7.2 ps for the timescale in which the bolometric photoresponse in graphene is generated. The photodetectors were fabricated on 6″ silicon-on-insulator wafers in a semiconductor pilot line, demonstrating the scalable fabrication of high-performance graphene based devices.

24-26  GHz radio-over-fiber and free-space optics for fifth-generation systems.

Science.gov (United States)

Bohata, Jan; Komanec, Matěj; Spáčil, Jan; Ghassemlooy, Zabih; Zvánovec, Stanislav; Slavík, Radan

2018-03-01

This Letter outlines radio-over-fiber combined with radio-over-free-space optics (RoFSO) and radio frequency free-space transmission, which is of particular relevance for fifth-generation networks. Here, the frequency band of 24-26 GHz is adopted to demonstrate a low-cost, compact, and high-energy-efficient solution based on the direct intensity modulation and direct detection scheme. For our proof-of-concept demonstration, we use 64 quadrature amplitude modulation with a 100 MHz bandwidth. We assess the link performance by exposing the RoFSO section to atmospheric turbulence conditions. Further, we show that the measured minimum error vector magnitude (EVM) is 4.7% and also verify that the proposed system with the free-space-optics link span of 100 m under strong turbulence can deliver an acceptable EVM of <9% with signal-to-noise ratio levels of 22 dB and 10 dB with and without turbulence, respectively.

GHz-rate optical parametric amplifier in hydrogenated amorphous silicon

International Nuclear Information System (INIS)

Wang, Ke-Yao; Foster, Amy C

2015-01-01

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)

Design of dual band FSS by using quadruple L-slot technique

Science.gov (United States)

Fauzi, Noor Azamiah Md; Aziz, Mohamad Zoinol Abidin Abd.; Said, Maizatul Alice Meor; Othman, Mohd Azlishah; Ahmad, Badrul Hisham; Malek, Mohd Fareq Abd

2015-05-01

This paper presents a new design of dual band frequency selective surface (FSS) for band pass microwave transmission application. FSS can be used on energy saving glass to improve the transmission of wireless communication signals through the glass. The microwave signal will be attenuate when propagate throughout the different structure such as building. Therefore, some of the wireless communication system cannot be used in the optimum performance. The aim of this paper is designed, simulated and analyzed the new dual band FSS structure for microwave transmission. This design is based on a quadruple L slot combined with cross slot to produce pass band at 900 MHz and 2.4 GHz. The vertical of pair inverse L slot is used as the band pass for the frequency of 2.4GHz. While, the horizontal of pair inverse L slot is used as the band pass at frequency 900MHz. This design is simulated and analyzed by using Computer Simulation Technology (CST) Microwave Studio (MWS) software. The characteristics of the transmission (S21) and reflection (S11) of the dual band FSS were simulater and analyzed. The bandwidth of the first band is 118.91MHz which covered the frequency range from 833.4MHz until 952.31MHz. Meanwhile, the bandwidth for the second band is 358.84MHz which covered the frequency range from 2.1475GHz until 2.5063GHz. The resonance/center frequency of this design is obtained at 900MHz with a 26.902dB return loss and 2.37GHz with 28.506dB a return loss. This FSS is suitable as microwave filter for GSM900 and WLAN 2.4GHz application.

A 31 GHz Survey of Low-Frequency Selected Radio Sources

Science.gov (United States)

Mason, B. S.; Weintraub, L.; Sievers, J.; Bond, J. R.; Myers, S. T.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.

2009-10-01

The 100 m Robert C. Byrd Green Bank Telescope and the 40 m Owens Valley Radio Observatory telescope have been used to conduct a 31 GHz survey of 3165 known extragalactic radio sources over 143 deg2 of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4 GHz flux densities of 3-10 mJy. The resulting 31 GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31 GHz spectral indices of these sources, we find a mean 31-1.4 GHz flux ratio of 0.110 ± 0.003 corresponding to a spectral index of α = -0.71 ± 0.01 (S ν vprop να) 9.0% ± 0.8% of sources have α > - 0.5 and 1.2% ± 0.2% have α > 0. By combining this spectral-index distribution with 1.4 GHz source counts, we predict 31 GHz source counts in the range 1 mJy S 31) = (16.7 ± 1.7) deg-2(S 31/1 mJy)-0.80±0.07. We also assess the contribution of mJy-level (S 1.4 GHz < 3.4 mJy) radio sources to the 31 GHz cosmic microwave background power spectrum, finding a mean power of ell(ell + 1)C src ell/(2π) = 44 ± 14 μK2 and a 95% upper limit of 80 μK2 at ell = 2500. Including an estimated contribution of 12 μK2 from the population of sources responsible for the turn-up in counts below S 1.4 GHz = 1 mJy, this amounts to 21% ± 7% of what is needed to explain the CBI high-ell excess signal, 275 ± 63 μK2. These results are consistent with other measurements of the 31 GHz point-source foreground.

Managing high-bandwidth real-time data storage

Energy Technology Data Exchange (ETDEWEB)

Bigelow, David D. [Los Alamos National Laboratory; Brandt, Scott A [Los Alamos National Laboratory; Bent, John M [Los Alamos National Laboratory; Chen, Hsing-Bung [Los Alamos National Laboratory

2009-09-23

There exist certain systems which generate real-time data at high bandwidth, but do not necessarily require the long-term retention of that data in normal conditions. In some cases, the data may not actually be useful, and in others, there may be too much data to permanently retain in long-term storage whether it is useful or not. However, certain portions of the data may be identified as being vitally important from time to time, and must therefore be retained for further analysis or permanent storage without interrupting the ongoing collection of new data. We have developed a system, Mahanaxar, intended to address this problem. It provides quality of service guarantees for incoming real-time data streams and simultaneous access to already-recorded data on a best-effort basis utilizing any spare bandwidth. It has built in mechanisms for reliability and indexing, can scale upwards to meet increasing bandwidth requirements, and handles both small and large data elements equally well. We will show that a prototype version of this system provides better performance than a flat file (traditional filesystem) based version, particularly with regard to quality of service guarantees and hard real-time requirements.

A New 95 GHz Methanol Maser Catalog. I. Data

Energy Technology Data Exchange (ETDEWEB)

Yang, Wenjin; Xu, Ye; Lu, Dengrong; Ju, Binggang; Li, Yingjie [Purple Mountain Observatory, Chinese Academy of Science, Nanjing 210008 (China); Chen, Xi [Center for Astrophysics, GuangZhou University, Guangzhou 510006 (China); Ellingsen, Simon P., E-mail: wjyang@pmo.ac.cn, E-mail: xuye@pmo.ac.cn, E-mail: chenxi@shao.ac.cn [School of Physical Sciences, University of Tasmania, Hobart, Tasmania (Australia)

2017-08-01

The Purple Mountain Observatory 13.7 m radio telescope has been used to search for 95 GHz (8{sub 0}–7{sub 1}A{sup +}) class I methanol masers toward 1020 Bolocam Galactic Plane Survey (BGPS) sources, leading to 213 detections. We have compared the line width of the methanol and HCO{sup +} thermal emission in all of the methanol detections, and on that basis, we find that 205 of the 213 detections are very likely to be masers. This corresponds to an overall detection rate of 95 GHz methanol masers toward our BGPS sample of 20%. Of the 205 detected masers, 144 (70%) are new discoveries. Combining our results with those of previous 95 GHz methanol maser searches, a total of 481 95 GHz methanol masers are now known. We have compiled a catalog listing the locations and properties of all known 95 GHz methanol masers.

77 FR 45558 - 4.9 GHz Band

Science.gov (United States)

2012-08-01

..., our rules currently require 4.9 GHz licensees to ``cooperate in the selection and use of channels in... directional and thus can be represented as narrow paths on a coordination map; in contrast, they note, the low-power, less- directional, geographically-dispersed links in a 4.9 GHz network must be represented as a...

Particle identification using digital pulse shape discrimination in a nTD silicon detector with a 1 GHz sampling digitizer

Science.gov (United States)

Mahata, K.; Shrivastava, A.; Gore, J. A.; Pandit, S. K.; Parkar, V. V.; Ramachandran, K.; Kumar, A.; Gupta, S.; Patale, P.

2018-06-01

In beam test experiments have been carried out for particle identification using digital pulse shape analysis in a 500 μm thick Neutron Transmutation Doped (nTD) silicon detector with an indigenously developed FPGA based 12 bit resolution, 1 GHz sampling digitizer. The nTD Si detector was used in a low-field injection setup to detect light heavy-ions produced in reactions of ∼ 5 MeV/A 7Li and 12C beams on different targets. Pulse height, rise time and current maximum have been obtained from the digitized charge output of a high bandwidth charge and current sensitive pre-amplifier. Good isotopic separation have been achieved using only the digitized charge output in case of light heavy-ions. The setup can be used for charged particle spectroscopy in nuclear reactions involving light heavy-ions around the Coulomb barrier energies.

Anisotropy in the Microwave Sky at 90 GHz: Results From Python III

OpenAIRE

Platt, S. R.; Kovac, J.; Dragovan, M.; Peterson, J. B.; Ruhl, J. E.

1996-01-01

The third year of observations with the Python microwave background experiment densely sample a $5.5^o\\times 22^o$ region of sky that includes the fields measured during the first two years of observations with this instrument. The sky is sampled in two multipole bands centered at $l \\approx 92$ and $l \\approx 177$. These two data sets are analyzed to place limits on fluctuations in the microwave sky at 90 GHz. Interpreting the observed fluctuations as anisotropy in the cosmic microwave backg...

High-Q Variable Bandwidth Passive Filters for Software Defined Radio

NARCIS (Netherlands)

Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

2001-01-01

An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper describes a technique for channel filtering, in which two passive filters are combined to obtain a variable bandwidth. Passive filters have the advantage of

High-Q variable bandwidth passive filters for Software Defined Radio

NARCIS (Netherlands)

Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper describes a technique for channel filtering, in which two passive filters are combined to obtain a variable bandwidth. Passive filters have the advantage of

A 1.8 GHz Voltage-Controlled Oscillator using CMOS Technology

Science.gov (United States)

Maisurah, M. H. Siti; Emran, F. Nazif; Norman Fadhil, Idham M.; Rahim, A. I. Abdul; Razman, Y. Mohamed

2011-05-01

A Voltage-Controlled Oscillator (VCO) for 1.8 GHz application has been designed using a combination of both 0.13 μm and 0.35 μm CMOS technology. The VCO has a large tuning range, which is from 1.39 GHz to 1.91 GHz, using a control voltage from 0 to 3V. The VCO exhibits a low phase-noise at 1.8 GHz which is around -119.8dBc/Hz at a frequency offset of 1 MHz.

Metasurface Reflector (MSR Loading for High Performance Small Microstrip Antenna Design.

Directory of Open Access Journals (Sweden)

Md Rezwanul Ahsan

Full Text Available A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15 is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%, 467 to 606 MHz (29% and 758 MHz to 1062 MHz (40% for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz RFID, WiMAX (3.5/5.5 GHz and WLAN (5.2/5.8 GHz applications.

Moiré volume Bragg grating filter with tunable bandwidth.

Science.gov (United States)

Mokhov, Sergiy; Ott, Daniel; Divliansky, Ivan; Zeldovich, Boris; Glebov, Leonid

2014-08-25

We propose a monolithic large-aperture narrowband optical filter based on a moiré volume Bragg grating formed by two sequentially recorded gratings with slightly different resonant wavelengths. Such recording creates a spatial modulation of refractive index with a slowly varying sinusoidal envelope. By cutting a specimen at a small angle, to a thickness of one-period of this envelope, the longitudinal envelope profile will shift from a sine profile to a cosine profile across the face of the device. The transmission peak of the filter has a tunable bandwidth while remaining at a fixed resonant wavelength by a transversal shift of incidence position. Analytical expressions for the tunable bandwidth of such a filter are calculated and experimental data from a filter operating at 1064 nm with bandwidth range 30-90 pm is demonstrated.

A low noise 665 GHz SIS quasi-particle waveguide receiver

Science.gov (United States)

Kooi, J. W.; Walker, C. K.; Leduc, H. G.; Hunter, T. R.; Benford, D. J.; Phillips, T. G.

1993-01-01

Recent results on a 565-690 GHz SIS heterodyne receiver employing a 0.36 micron(sup 2) Nb/AlOx/Nb SIS tunnel junction with high quality circular non-contacting back short and E-plane tuners in a full height wave guide mount are reported. No resonant tuning structures were incorporated in the junction design at this time, even though such structures are expected to help the performance of the receiver. The receiver operates to at least the gap frequency of Niobium, approximately 680 GHz. Typical receiver noise temperatures from 565-690 GHz range from 160K to 230K with a best value of 185K DSB at 648 GHz. With the mixer cooled from 4.3K to 2K the measured receiver noise temperatures decreased by approximately 15 percent, giving roughly 180K DSB from 660 to 680 GHz. The receiver has a full 1 GHz IF pass band and was successfully installed at the Caltech Submillimeter Observatory in Hawaii.

Magnetic films for GHz applications (abstract)

International Nuclear Information System (INIS)

Korenivski, V.; van Dover, R.B.

1997-01-01

Tremendous growth of the communications industry and the increasingly high demand for low-cost light-weight/small-size products drive technology to designs with a high degree of integration. In particular, planar inductors used in integrated circuits with significantly improved inductance per unit area characteristics are needed for further miniaturization of cellular phones operating at 0.95 and 1.9 GHz. Little has been done, however, to use magnetic films to improve the performance and/or reduce size of planar magnetic flux devices. The successful thin-film material would have a high ferromagnetic resonance (FMR) frequency (well above the operating frequency of the device), large permaeability, and low magnetic loss, and very importantly be technologically attractive, i.e., be process compatible with IC technology and have as few preparation steps as possible. Here, we report on fabrication of metallic ferromagnetic films of CoNbZr, CoNbZr/AlN mulitilayered laminates, and exchange-biased structures suitable for GHz applications. Lamination of CoNbZr with thin insulating layers of AlN is shown to significantly improve the microstructure and dc magnetic properties of the films having thicknesses >0.2 μm, as well as to be effective in suppressing eddy current losses at frequencies up to 1 endash 2 GHz. We use exchange biasing to increase the FMR frequency of soft CoNbZr. In-plane unidirectional anisotropy fields of ∼50 Oe are achieved, which result in FMR frequencies >2 GHz. Permeability values of ∼200 with quality factors of ∼10 at 1 GHz are demonstrated. The films are deposited at room temperature and require no postdeposition processing. Application of these films in planar inductors is discussed.copyright 1997 American Institute of Physics

Fixed-Tuned Waveguide 0.6 THz SIS Mixer with Wide Band IF

NARCIS (Netherlands)

Baryshev, A.; Lauria, E.; Hesper, R.; Zijistra, T.; Wild, W.

2002-01-01

The Atacama Large Millimeter Array (ALMA) requires low noise SIS receivers for frequencies from about 80 GHz to 950 GHz with a very large IF bandwidth (8 GHz SSB upper or lower sideband, 8 GHz DSB or 4 GHz dual sideband, upper and lower sideband). Since there will be a large number of antennas in

Terahertz bandwidth photonic Hilbert transformers based on synthesized planar Bragg grating fabrication.

Science.gov (United States)

Sima, Chaotan; Gates, J C; Holmes, C; Mennea, P L; Zervas, M N; Smith, P G R

2013-09-01

Terahertz bandwidth photonic Hilbert transformers are proposed and experimentally demonstrated. The integrated device is fabricated via a direct UV grating writing technique in a silica-on-silicon platform. The photonic Hilbert transformer operates at bandwidths of up to 2 THz (~16 nm) in the telecom band, a 10-fold greater bandwidth than any previously reported experimental approaches. Achieving this performance requires detailed knowledge of the system transfer function of the direct UV grating writing technique; this allows improved linearity and yields terahertz bandwidth Bragg gratings with improved spectral quality. By incorporating a flat-top reflector and Hilbert grating with a waveguide coupler, an ultrawideband all-optical single-sideband filter is demonstrated.

Dynamic Bandwidth Allocation with Effective Utilization of Polling Interval over WDM/TDM PON

Science.gov (United States)

Ni, Cuiping; Gan, Chaoqin; Gao, Ziyue

2014-12-01

WDM/TDM (wavelength-division multiplexing/time-division multiplexing) PON (passive optical network) appears to be an attractive solution for the next generation optical access networks. Dynamic bandwidth allocation (DBA) plays a crucial role in efficiently and fairly allocating the bandwidth among all users in WDM/TDM PON. In this paper, two dynamic bandwidth allocation schemes (DBA1 and DBA2) are proposed to eliminate the idle time of polling cycles (i.e. polling interval), improve bandwidth utilization and make full use of bandwidth resources. The two DBA schemes adjust the time slot of sending request information and make fair scheduling among users to achieve the effective utilization of polling interval in WDM/TDM PON. The simulation and theoretical analyses verify that the proposed schemes outperform the conventional DBA scheme. We also make comparisons between the two schemes in terms of bandwidth utilization and average packet delay to further demonstrate the effectiveness of the scheme of DBA2.

A general framework for performance guaranteed green data center networking

OpenAIRE

Wang, Ting; Xia, Yu; Muppala, Jogesh; Hamdi, Mounir; Foufou, Sebti

2014-01-01

From the perspective of resource allocation and routing, this paper aims to save as much energy as possible in data center networks. We present a general framework, based on the blocking island paradigm, to try to maximize the network power conservation and minimize sacrifices of network performance and reliability. The bandwidth allocation mechanism together with power-aware routing algorithm achieve a bandwidth guaranteed tighter network. Besides, our fast efficient heuristics for allocatin...

Time-optimal control with finite bandwidth

Science.gov (United States)

Hirose, M.; Cappellaro, P.

2018-04-01

Time-optimal control theory provides recipes to achieve quantum operations with high fidelity and speed, as required in quantum technologies such as quantum sensing and computation. While technical advances have achieved the ultrastrong driving regime in many physical systems, these capabilities have yet to be fully exploited for the precise control of quantum systems, as other limitations, such as the generation of higher harmonics or the finite response time of the control apparatus, prevent the implementation of theoretical time-optimal control. Here we present a method to achieve time-optimal control of qubit systems that can take advantage of fast driving beyond the rotating wave approximation. We exploit results from time-optimal control theory to design driving protocols that can be implemented with realistic, finite-bandwidth control fields, and we find a relationship between bandwidth limitations and achievable control fidelity.

Analysis of blocking probability for OFDM-based variable bandwidth optical network

Science.gov (United States)

Gong, Lei; Zhang, Jie; Zhao, Yongli; Lin, Xuefeng; Wu, Yuyao; Gu, Wanyi

2011-12-01

Orthogonal Frequency Division Multiplexing (OFDM) has recently been proposed as a modulation technique. For optical networks, because of its good spectral efficiency, flexibility, and tolerance to impairments, optical OFDM is much more flexible compared to traditional WDM systems, enabling elastic bandwidth transmissions, and optical networking is the future trend of development. In OFDM-based optical network the research of blocking rate has very important significance for network assessment. Current research for WDM network is basically based on a fixed bandwidth, in order to accommodate the future business and the fast-changing development of optical network, our study is based on variable bandwidth OFDM-based optical networks. We apply the mathematical analysis and theoretical derivation, based on the existing theory and algorithms, research blocking probability of the variable bandwidth of optical network, and then we will build a model for blocking probability.

IMPLEMENTASI MANAJEMEN BANDWIDTH DENGAN DISIPLIN ANTRIAN HIERARCHICAL TOKEN BUCKET (HTB PADA SISTEM OPERASI LINUX

Directory of Open Access Journals (Sweden)

Muhammad Nugraha

2017-01-01

Full Text Available Important Problem on Internet networking is exhausted resource and bandwidth by some user while other user did not get service properly. To overcome that problem we need to implement traffic control and bandwidth management system in router. In this research author want to implement Hierarchical Token Bucket algorithm as queue discipline (qdisc to get bandwidth management accurately in order the user can get bandwidth properly. The result of this research is form the management bandwidth cheaply and efficiently by using Hierarchical Token Bucket qdisc on Linux operating system were able to manage the user as we want.

Implementasi Manajemen Bandwidth Dengan Disiplin Antrian Hierarchical Token Bucket (HTB Pada Sistem Operasi Linux

Directory of Open Access Journals (Sweden)

Muhammad Nugraha

2016-09-01

Full Text Available Important Problem on Internet networking is exhausted resource and bandwidth by some user while other user did not get service properly. To overcome that problem we need to implement traffic control and bandwidth management system in router. In this research author want to implement Hierarchical Token Bucket algorithm as queue discipline (qdisc to get bandwidth management accurately in order the user can get bandwidth properly. The result of this research is form the management bandwidth cheaply and efficiently by using Hierarchical Token Bucket qdisc on Linux operating system were able to manage the user as we want.

Low cost and thin metasurface for ultra wide band and wide angle polarization insensitive radar cross section reduction

Science.gov (United States)

Ameri, Edris; Esmaeli, Seyed Hassan; Sedighy, Seyed Hassan

2018-05-01

A planar low cost and thin metasurface is proposed to achieve ultra-wideband radar cross section (RCS) reduction with stable performance with respect to polarization and incident angles. This metasurface is composed of two different artificial magnetic conductor unit cells arranged in a chessboard like configuration. These unit cells have a Jerusalem cross pattern with different thicknesses, which results in wideband out-phase reflection and RCS reduction, consequently. The designed metasurface reduces RCS more than 10-dB from 13.6 GHz to 45.5 GHz (108% bandwidth) and more than 20-dB RCS from 15.2 GHz to 43.6 GHz (96.6%). Moreover, the 10-dB RCS reduction bandwidth is very stable (more than 107%) for both TE and TM polarizations. The good agreement between simulations and measurement results proves the design, properly. The ultra-wide bandwidth, low cost, low profile, and stable performance of this metasurface prove its high capability compared with the state-of-the-art references.

A study of 60 GHz intersatellite link applications

Science.gov (United States)

Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.

Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.

A study of 60 GHz intersatellite link applications

Science.gov (United States)

Anzic, G.; Connolly, D. J.; Haugland, E. J.; Kosmahl, H. G.; Chitwood, J. S.

1983-01-01

Applications of intersatellite links operating at 60 GHz are reviewed. Likely scenarios, ranging from transmission of moderate and high data rates over long distances to low data rates over short distances are examined. A limited parametric tradeoff is performed with system variables such as radiofrequency power, receiver noise temperature, link distance, data rate, and antenna size. Present status is discussed and projections are given for both electron tube and solid state transmitter technologies. Monolithic transmit and receive module technology, already under development at 20 to 30 GHz, is reviewed and its extension to 60 GHz, and possible applicability is discussed.

The 30/20 GHz communications system functional requirements

Science.gov (United States)

Siperko, C. M.; Frankfort, M.; Markham, R.; Wall, M.

1981-01-01

The characteristics of 30/20 GHz usage in satellite systems to be used in support of projected communication requirements of the 1990's are defined. A requirements analysis which develops projected market demand for satellite services by general and specialized carriers and an analysis of the impact of propagation and system constraints on 30/20 GHz operation are included. A set of technical performance characteristics for the 30/20 GHz systems which can serve the resulting market demand and the experimental program necessary to verify technical and operational aspects of the proposed systems is also discussed.

BMCloud: Minimizing Repair Bandwidth and Maintenance Cost in Cloud Storage

Directory of Open Access Journals (Sweden)

Chao Yin

2013-01-01

Full Text Available To protect data in cloud storage, fault tolerance and efficient recovery become very important. Recent studies have developed numerous solutions based on erasure code techniques to solve this problem using functional repairs. However, there are two limitations to address. The first one is consistency since the Encoding Matrix (EM is different among clouds. The other one is repairing bandwidth, which is a concern for most of us. We addressed these two problems from both theoretical and practical perspectives. We developed BMCloud, a new low repair bandwidth, low maintenance cost cloud storage system, which aims to reduce repair bandwidth and maintenance cost. The system employs both functional repair and exact repair while it inherits advantages from the both. We propose the JUDGE_STYLE algorithm, which can judge whether the system should adopt exact repair or functional repair. We implemented a networked storage system prototype and demonstrated our findings. Compared with existing solutions, BMCloud can be used in engineering to save repair bandwidth and degrade maintenance significantly.

Coarse-grain bandwidth estimation techniques for large-scale network

Science.gov (United States)

Cheung, Kar-Ming; Jennings, E.

In this paper, we describe a top-down analysis and simulation approach to size the bandwidths of a store-and-forward network for a given network topology, a mission traffic scenario, and a set of data types with different latency requirements. We use these techniques to estimate the wide area network (WAN) bandwidths of the ground links for different architecture options of the proposed Integrated Space Communication and Navigation (SCaN) Network.

ASTEROID SIZING BY RADIOGALAXY OCCULTATION AT 5 GHZ

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K.; Muinonen, K.; Poutanen, M. [Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430 Masala (Finland); Bach, U. [Max-Planck-Institut für Radioastronomie, Radioobservatorium Effelsberg, Max-Planck-Str. 28, D-53902 Bad Münstereifel-Effelsberg (Germany); Petrov, L., E-mail: kimmo.lehtinen@nls.fi [Astrogeo Center, Falls Church, VA 22043 (United States)

2016-05-10

Stellar occultations by asteroids observed at visual wavelengths have been an important tool for studying the size and shape of asteroids and for revising the orbital parameters of asteroids. At radio frequencies, a shadow of an asteroid on the Earth is dominated by diffraction effects. Here, we show, for the first time, that a single observation of an occultation of a compact radio source at a frequency of 5 GHz can be used to derive the effective size of the occulting object and to derive the distance between the observer and the center of the occultation path on the Earth. The derived diameter of the occulting object, asteroid (115) Thyra, is 75 ± 6 km. The observed occultation profile shows features that cannot be explained by diffraction of a single asteroid.

The Prediction of Bandwidth On Need Computer Network Through Artificial Neural Network Method of Backpropagation

Directory of Open Access Journals (Sweden)

Ikhthison Mekongga

2014-02-01

Full Text Available The need for bandwidth has been increasing recently. This is because the development of internet infrastructure is also increasing so that we need an economic and efficient provider system. This can be achieved through good planning and a proper system. The prediction of the bandwidth consumption is one of the factors that support the planning for an efficient internet service provider system. Bandwidth consumption is predicted using ANN. ANN is an information processing system which has similar characteristics as the biologic al neural network.  ANN  is  chosen  to  predict  the  consumption  of  the  bandwidth  because  ANN  has  good  approachability  to  non-linearity.  The variable used in ANN is the historical load data. A bandwidth consumption information system was built using neural networks  with a backpropagation algorithm to make the use of bandwidth more efficient in the future both in the rental rate of the bandwidth and in the usage of the bandwidth.Keywords: Forecasting, Bandwidth, Backpropagation

Spectral signature barcodes based on S-shaped Split Ring Resonators (S-SRRs

Directory of Open Access Journals (Sweden)

Herrojo Cristian

2016-01-01

Full Text Available In this paper, it is shown that S-shaped split ring resonators (S-SRRs are useful particles for the implementation of spectral signature (i.e., a class of radiofrequency barcodes based on coplanar waveguide (CPW transmission lines loaded with such resonant elements. By virtue of its S shape, these resonators are electrically small. Hence S-SRRs are of interest for the miniaturization of the barcodes, since multiple resonators, each tuned at a different frequency, are used for encoding purposes. In particular, a 10-bit barcode occupying 1 GHz spectral bandwidth centered at 2.5 GHz, with dimensions of 9 cm2, is presented in this paper.

47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite service. 25.143 Section 25.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

A Statistical Approach for Gain Bandwidth Prediction of Phoenix-Cell Based Reflect arrays

Directory of Open Access Journals (Sweden)

Hassan Salti

2018-01-01

Full Text Available A new statistical approach to predict the gain bandwidth of Phoenix-cell based reflectarrays is proposed. It combines the effects of both main factors that limit the bandwidth of reflectarrays: spatial phase delays and intrinsic bandwidth of radiating cells. As an illustration, the proposed approach is successfully applied to two reflectarrays based on new Phoenix cells.

Analysis of Resonance Response Performance of C-Band Antenna Using Parasitic Element

Science.gov (United States)

Islam, M. T.; Misran, N.; Mandeep, J. S.

2014-01-01

Analysis of the resonance response improvement of a planar C-band (4–8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency. PMID:24895643

High bandwidth concurrent processing on commodity platforms

CERN Document Server

Boosten, M; Van der Stok, P D V

1999-01-01

The I/O bandwidth and real-time processing power required for high- energy physics experiments is increasing rapidly over time. The current requirements can only be met by using large-scale concurrent processing. We are investigating the use of a large PC cluster interconnected by Fast and Gigabit Ethernet to meet the performance requirements of the ATLAS second level trigger. This architecture is attractive because of its performance and competitive pricing. A major problem is obtaining frequent high-bandwidth I/O without sacrificing the CPU's processing power. We present a tight integration of a user-level scheduler and a zero-copy communication layer. This system closely approaches the performance of the underlying hardware in terms of both CPU power and I/O capacity. (0 refs).

Digital demodulator for wide bandwidth SAR

DEFF Research Database (Denmark)

Jørgensen, Jørn Hjelm

2000-01-01

A novel approach to the design of efficient digital quadrature demodulators for wide bandwidth SAR systems is described. Efficiency is obtained by setting the intermediate frequency to 1/4 the ADC sampling frequency. One channel is made filter-free by synchronizing the local oscillator...

Manajemen Bandwidth Simple Queue dan Queue Tree pada PT. Endorsindo Makmur Selaras

OpenAIRE

Budiman, Arif

2015-01-01

  The purpose of this study is to analyze and optimize the bandwidth management at PT. Endorsindo Makmur Selaras, with the expectation that the distribution of bandwidth can be evenly distributed to each employee so that the employee can improve performance and quality of the company. Research methods used include analysis methods (survey and interview system that runs directly on the user) and to optimize bandwidth management method to configure the proxy using the Queue Tree. The re...

1.3 GHz superconducting RF cavity program at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Ginsburg, C.M.; Arkan, T.; Barbanotti, S.; Carter, H.; Champion, M.; Cooley, L.; Cooper, C.; Foley, M.; Ge, M.; Grimm, C.; Harms, E.; /Fermilab

2011-03-01

At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules (CMs) for Project X, an International Linear Collider (ILC), or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.

Bandwidth limitations in current mode and voltage mode integrated feedback amplifiers

DEFF Research Database (Denmark)

Bruun, Erik

1995-01-01

loop bandwidth remains constant for a feedback amplifier. The constant-bandwidth relations of such amplifier designs are reviewed in this paper and they are combined with the constraints imposed by technology when the feedback amplifier is to be designed in an integrated technology. From this analysis...

Compression of Video Tracking and Bandwidth Balancing Routing in Wireless Multimedia Sensor Networks

Directory of Open Access Journals (Sweden)

Yin Wang

2015-12-01

Full Text Available There has been a tremendous growth in multimedia applications over wireless networks. Wireless Multimedia Sensor Networks(WMSNs have become the premier choice in many research communities and industry. Many state-of-art applications, such as surveillance, traffic monitoring, and remote heath care are essentially video tracking and transmission in WMSNs. The transmission speed is constrained by the big file size of video data and fixed bandwidth allocation in constant routing paths. In this paper, we present a CamShift based algorithm to compress the tracking of videos. Then we propose a bandwidth balancing strategy in which each sensor node is able to dynamically select the node for the next hop with the highest potential bandwidth capacity to resume communication. Key to this strategy is that each node merely maintains two parameters that contain its historical bandwidth varying trend and then predict its near future bandwidth capacity. Then, the forwarding node selects the next hop with the highest potential bandwidth capacity. Simulations demonstrate that our approach significantly increases the data received by the sink node and decreases the delay on video transmission in Wireless Multimedia Sensor Network environments.

Estimating individual listeners’ auditory-filter bandwidth in simultaneous and non-simultaneous masking

DEFF Research Database (Denmark)

Buchholz, Jörg; Caminade, Sabine; Strelcyk, Olaf

2010-01-01

Frequency selectivity in the human auditory system is often measured using simultaneous masking of tones presented in notched noise. Based on such masking data, the equivalent rectangular bandwidth (ERB) of the auditory filters can be derived by applying the power spectrum model of masking....... Considering bandwidth estimates from previous studies based on forward masking, only average data across a number of subjects have been considered. The present study is concerned with bandwidth estimates in simultaneous and forward masking in individual normal-hearing subjects. In order to investigate...... the reliability of the individual estimates, a statistical resampling method is applied. It is demonstrated that a rather large set of experimental data is required to reliably estimate auditory filter bandwidth, particularly in the case of simultaneous masking. The poor overall reliability of the filter...

Bandwidth-sharing in LHCONE, an analysis of the problem

Science.gov (United States)

Wildish, T.

2015-12-01

The LHC experiments have traditionally regarded the network as an unreliable resource, one which was expected to be a major source of errors and inefficiency at the time their original computing models were derived. Now, however, the network is seen as much more capable and reliable. Data are routinely transferred with high efficiency and low latency to wherever computing or storage resources are available to use or manage them. Although there was sufficient network bandwidth for the experiments’ needs during Run-1, they cannot rely on ever-increasing bandwidth as a solution to their data-transfer needs in the future. Sooner or later they need to consider the network as a finite resource that they interact with to manage their traffic, in much the same way as they manage their use of disk and CPU resources. There are several possible ways for the experiments to integrate management of the network in their software stacks, such as the use of virtual circuits with hard bandwidth guarantees or soft real-time flow-control, with somewhat less firm guarantees. Abstractly, these can all be considered as the users (the experiments, or groups of users within the experiment) expressing a request for a given bandwidth between two points for a given duration of time. The network fabric then grants some allocation to each user, dependent on the sum of all requests and the sum of available resources, and attempts to ensure the requirements are met (either deterministically or statistically). An unresolved question at this time is how to convert the users’ requests into an allocation. Simply put, how do we decide what fraction of a network's bandwidth to allocate to each user when the sum of requests exceeds the available bandwidth? The usual problems of any resourcescheduling system arise here, namely how to ensure the resource is used efficiently and fairly, while still satisfying the needs of the users. Simply fixing quotas on network paths for each user is likely to lead

Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

Directory of Open Access Journals (Sweden)

Chandan Kumar Ghosh

2012-01-01

Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

A MAP blind image deconvolution algorithm with bandwidth over-constrained

Science.gov (United States)

Ren, Zhilei; Liu, Jin; Liang, Yonghui; He, Yulong

2018-03-01

We demonstrate a maximum a posteriori (MAP) blind image deconvolution algorithm with bandwidth over-constrained and total variation (TV) regularization to recover a clear image from the AO corrected images. The point spread functions (PSFs) are estimated by bandwidth limited less than the cutoff frequency of the optical system. Our algorithm performs well in avoiding noise magnification. The performance is demonstrated on simulated data.

Should drivers be operating within an automation-free bandwidth? Evaluating haptic steering support systems with different levels of authority.

Science.gov (United States)

Petermeijer, Sebastiaan M; Abbink, David A; de Winter, Joost C F

2015-02-01

The aim of this study was to compare continuous versus bandwidth haptic steering guidance in terms of lane-keeping behavior, aftereffects, and satisfaction. An important human factors question is whether operators should be supported continuously or only when tolerance limits are exceeded. We aimed to clarify this issue for haptic steering guidance by investigating costs and benefits of both approaches in a driving simulator. Thirty-two participants drove five trials, each with a different level of haptic support: no guidance (Manual); guidance outside a 0.5-m bandwidth (Band1); a hysteresis version of Band1, which guided back to the lane center once triggered (Band2); continuous guidance (Cont); and Cont with double feedback gain (ContS). Participants performed a reaction time task while driving. Toward the end of each trial, the guidance was unexpectedly disabled to investigate aftereffects. All four guidance systems prevented large lateral errors (>0.7 m). Cont and especially ContS yielded smaller lateral errors and higher time to line crossing than Manual, Band1, and Band2. Cont and ContS yielded short-lasting aftereffects, whereas Band1 and Band2 did not. Cont yielded higher self-reported satisfaction and faster reaction times than Band1. Continuous and bandwidth guidance both prevent large driver errors. Continuous guidance yields improved performance and satisfaction over bandwidth guidance at the cost of aftereffects and variability in driver torque (indicating human-automation conflicts). The presented results are useful for designers of haptic guidance systems and support critical thinking about the costs and benefits of automation support systems.

Experimental study of a SINIS detector response time at 350 GHz signal frequency

Science.gov (United States)

Lemzyakov, S.; Tarasov, M.; Mahashabde, S.; Yusupov, R.; Kuzmin, L.; Edelman, V.

2018-03-01

Response time constant of a SINIS bolometer integrated in an annular ring antenna was measured at a bath temperature of 100 mK. Samples comprising superconducting aluminium electrodes and normal-metal Al/Fe strip connected to electrodes via tunnel junctions were fabricated on oxidized Si substrate using shadow evaporation. The bolometer was illuminated by a fast black-body radiation source through a band-pass filter centered at 350 GHz with a passband of 7 GHz. Radiation source is a thin NiCr film on sapphire substrate. For rectangular 10÷100 μs current pulse the radiation front edge was rather sharp due to low thermal capacitance of NiCr film and low thermal conductivity of substrate at temperatures in the range 1-4 K. The rise time of the response was ~1-10 μs. This time presumably is limited by technical reasons: high dynamic resistance of series array of bolometers and capacitance of a long twisted pair wiring from SINIS bolometer to a room-temperature amplifier.

Development of measurement protocols for quantum magnetometry

DEFF Research Database (Denmark)

Stark, Alexander

and protocols to enhance the lifetime and the coherences of the NV center with the overall goal of enhancing the capabilities of this sensor in the field of magnetometry. In order to realize complex protocols, a sophisticated software control of the measurement setup is required. A general software framework......, is serving as rigorous framework to reduce the complexity of the setup configuration by a fundamental separation of tasks. As a consequence, the general idea of this framework is not limited to experiments with color centers in diamond, but can find application in any laboratory environment. The measurement...... of magnetic fields in the high-frequency GHz regimes is challenging. In this thesis, a continuous dynamical decoupling protocol is developed and implemented, which extends the capabilities of the NV sensor to probe GHz signals with a narrow bandwidth. Moreover, the protocol protects the system from noise...

Packaging of microwave integrated circuits operating beyond 100 GHz

Science.gov (United States)

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.

360/degree/ digital phase detector with 100-kHz bandwidth

International Nuclear Information System (INIS)

Reid, D.W.; Riggin, D.; Fazio, M.V.; Biddle, R.S.; Patton, R.D.; Jackson, H.A.

1981-01-01

The general availability of digital circuit components with propagation delay times of a few nanoseconds makes a digital phase detector with good bandwidth feasible. Such a circuit has a distinct advantage over its analog counterpart because of its linearity over a wide range of phase shift. A description is given of a phase detector that is being built at Los Alamos National Laboratory for the Fusion Materials Irradiation Test (FMIT) project. The specifications are 100-kHz bandwidth, linearity of /plus or minus/1/degree/ over /plus or minus/180/degree/ of phase shift, and 0.66/degree/ resolution. To date, the circuit has achieved the bandwidth and resolution. The linearity is approximately /plus or minus/3/degree/ over /plus or minus/180/degree/ phase shift. 3 refs

450-nm GaN laser diode enables high-speed visible light communication with 9-Gbps QAM-OFDM.

Science.gov (United States)

Chi, Yu-Chieh; Hsieh, Dan-Hua; Tsai, Cheng-Ting; Chen, Hsiang-Yu; Kuo, Hao-Chung; Lin, Gong-Ru

2015-05-18

A TO-38-can packaged Gallium nitride (GaN) blue laser diode (LD) based free-space visible light communication (VLC) with 64-quadrature amplitude modulation (QAM) and 32-subcarrier orthogonal frequency division multiplexing (OFDM) transmission at 9 Gbps is preliminarily demonstrated over a 5-m free-space link. The 3-dB analog modulation bandwidth of the TO-38-can packaged GaN blue LD biased at 65 mA and controlled at 25°C is only 900 MHz, which can be extended to 1.5 GHz for OFDM encoding after throughput intensity optimization. When delivering the 4-Gbps 16-QAM OFDM data within 1-GHz bandwidth, the error vector magnitude (EVM), signal-to-noise ratio (SNR) and bit-error-rate (BER) of the received data are observed as 8.4%, 22.4 dB and 3.5 × 10(-8), respectively. By increasing the encoded bandwidth to 1.5 GHz, the TO-38-can packaged GaN blue LD enlarges its transmission capacity to 6 Gbps but degrades its transmitted BER to 1.7 × 10(-3). The same transmission capacity of 6 Gbps can also be achieved with a BER of 1 × 10(-6) by encoding 64-QAM OFDM data within 1-GHz bandwidth. Using the 1.5-GHz full bandwidth of the TO-38-can packaged GaN blue LD provides the 64-QAM OFDM transmission up to 9 Gbps, which successfully delivers data with an EVM of 5.1%, an SNR of 22 dB and a BER of 3.6 × 10(-3) passed the forward error correction (FEC) criterion.

47 CFR 25.139 - NGSO FSS coordination and information sharing between MVDDS licensees in the 12.2 GHz to 12.7 GHz...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false NGSO FSS coordination and information sharing between MVDDS licensees in the 12.2 GHz to 12.7 GHz band. 25.139 Section 25.139 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

2 ~ 5 times tunable repetition-rate multiplication of a 10 GHz pulse source using a linearly tunable, chirped fiber Bragg grating.

Science.gov (United States)

Lee, Ju Han; Chang, You; Han, Young-Geun; Kim, Sang; Lee, Sang

2004-08-23

We experimentally demonstrate a simple scheme for the tunable pulse repetition-rate multiplication based on the fractional Talbot effect in a linearly tunable, chirped fiber Bragg grating (FBG). The key component in this scheme is our linearly tunable, chirped FBG with no center wavelength shift, which was fabricated with the S-bending method using a uniform FBG. By simply tuning the group velocity dispersion of the chirped FBG, we readily multiply an original 8.5 ps, 10 GHz soliton pulse train by a factor of 2 ~ 5 to obtain high quality pulses at repetition-rates of 20 ~ 50 GHz without significantly changing the system configuration.

Distribute Off-Time Office Internet bandwidth Using Topology Mesh For Sorrounding Neighbour

Science.gov (United States)

Zendrato, Niskarto; Sihombing, Oloan; Laia, Yonata; Sabarita Barus, Ertina

2018-04-01

The Internet as one of the very rapidly growing information technology can provide data and information with wide world, complete, and up to date. Users can download and upload data such as the application file, multimedia and text through the Internet network. But for the Internet availability is still less equal access because of the lack of availability of adequate infrastructure, therefore the author make the utilization of bandwidth that can be establish Internet balancing although still on a small scale. By this research the authors use bandwidth from PT. Deltauli Home Teknikarya that where bandwidth necessity on when time off-time unused office, where the office always pay full for Internet connection even though at the time of the off-time. It’s many of the available bandwidth, so that the author is trying to take advantage of the bandwidth at the time of the off-time the office to be used by the community using radio connection link and use the radius server as user management and server to send sms and user and password to the users who want to enjoy free internet connection.

Coarse-Grain Bandwidth Estimation Techniques for Large-Scale Space Network

Science.gov (United States)

Cheung, Kar-Ming; Jennings, Esther

2013-01-01

In this paper, we describe a top-down analysis and simulation approach to size the bandwidths of a store-andforward network for a given network topology, a mission traffic scenario, and a set of data types with different latency requirements. We use these techniques to estimate the wide area network (WAN) bandwidths of the ground links for different architecture options of the proposed Integrated Space Communication and Navigation (SCaN) Network.

Fast Faraday Cup With High Bandwidth

Science.gov (United States)

Deibele, Craig E [Knoxville, TN

2006-03-14

A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

Graphene photodetectors with a bandwidth  >76 GHz fabricated in a 6″ wafer process line

International Nuclear Information System (INIS)

Schall, Daniel; Porschatis, Caroline; Otto, Martin; Neumaier, Daniel

2017-01-01

In recent years, the data traffic has grown exponentially and the forecasts indicate a huge market that could be addressed by communication infrastructure and service providers. However, the processing capacity, space, and energy consumption of the available technology is a serious bottleneck for the exploitation of these markets. Chip-integrated optical communication systems hold the promise of significantly improving these issues related to the current technology. At the moment, the answer to the question which material is best suited for ultrafast chip integrated communication systems is still open. In this manuscript we report on ultrafast graphene photodetectors with a bandwidth of more than 76 GHz well suitable for communication links faster than 100 GBit s −1 per channel. We extract an upper value of 7.2 ps for the timescale in which the bolometric photoresponse in graphene is generated. The photodetectors were fabricated on 6″ silicon-on-insulator wafers in a semiconductor pilot line, demonstrating the scalable fabrication of high-performance graphene based devices. (paper)

Bandwidth-dependent transformation of noise data f

OpenAIRE

P. Bormann;  

1998-01-01

Additional keywords: bandwidth dependence amplitudes, Dynamikbereich, Frequenzband, relative Bandbreite, spektrale Leistungsdichte der Bodenunruhe, Darstellungen der Bodenunruhespektren in verschiedenen kinematischen Einheiten, Transformation kinematischer Einheiten, Transformation von Spektren in Amplituden der Bodenbewegung, Abhaengigkeit der Amplituden von der Bandbreite

Fractal Based Triple Band High Gain Monopole Antenna

Science.gov (United States)

Pandey, Shashi Kant; Pandey, Ganga Prasad; Sarun, P. M.

2017-10-01

A novel triple-band microstrip fed planar monopole antenna is proposed and investigated. A fractal antenna is created by iterating a narrow pulse (NP) generator model at upper side of modified ground plane, which has a rhombic patch, for enhancing the bandwidth and gain. Three iterations are carried out to study the effects of fractal geometry on the antenna performance. The proposed antenna can operate over three frequency ranges viz, 3.34-4.8 GHz, 5.5-10.6 GHz and 13-14.96 GHz suitable for WLAN 5.2/5.8 GHz, WiMAX 3.5/5.5 GHz and X band applications respectively. Simulated and measured results are in good agreements with each others. Results show that antenna provides wide/ultra wide bandwidths, monopole like radiation patterns and very high antenna gains over the operating frequency bands.

Hybridizing polypyrrole chains with laminated and two-dimensional Ti3C2Tx toward high-performance electromagnetic wave absorption

Science.gov (United States)

Tong, Yuan; He, Man; Zhou, Yuming; Zhong, Xi; Fan, Lidan; Huang, Tingyuan; Liao, Qiang; Wang, Yongjuan

2018-03-01

In this study, multilayer sandwich heterostructural Ti3C2Tx MXenes decorated with polypyrrole chains have been synthesized successfully via HF etching treatment and in-situ chemical oxidative polymerization approach. The hybrids were investigated as EM wave absorbers for the first time. It is found that the composites consisting of 25 wt% Ti3C2Tx/PPy hybrids in a paraffin matrix exhibit a minimum reflection loss of -49.2 dB (∼99.99% absorption) at the thickness of 3.2 mm and a maximum effective absorption bandwidth of 4.9 GHz (12.4-17.3 GHz) corresponding to an absorber thickness of 2.0 mm. Additionally, a broad effective absorption bandwidth of 13.7 GHz (4.3-18.0 GHz) can be reached up by adjusting the thickness from 1.5 to 5.0 mm. Furthermore, the highest effective absorption bandwidth of 5.7 GHz can be reached when the mass fraction is 15 wt%. The enhanced comprehensive electromagnetic wave absorption has close correlation with the well-designed heterogeneous multilayered microstructure, generated heterogeneous interfaces, conductive paths, surface functional groups, localized defects and synergistic effect between laminated Ti3C2Tx and conductive polypyrrole network, which significantly improve impedance matching and attenuation abilities. The superior absorbing performance together with strong absorption and broad bandwidth endows the Ti3C2Tx/PPy hybrids with the potential prospect to be advanced EM wave absorbers.

Spatial and Temporal Characterization of Indoor Millimeter Wave Propagation at 24 GHz

Directory of Open Access Journals (Sweden)

Seok-hwan Min

2016-01-01

Full Text Available Indoor millimeter wave propagation at the frequency of 24 GHz is studied by experimental methods. Measurements are performed to obtain temporal and spatial channel model using a channel sounder and rotating antennas in a corridor. The measured impulse responses are processed to obtain compact channel model following Saleh-Valenzuela’s model. The responses are compared with those of 5.3 GHz for the same test sites. Angular spread of 24 GHz is found to be smaller than that of 5.3 GHz, while echoes of 24 GHz are found to be longer than those of 5.3 GHz.

Development of a 200 W CW high efficiency traveling wave tube at 12 GHz. [for use in communication technology satellites

Science.gov (United States)

Christensen, J. A.; Tammaru, I.

1974-01-01

The design, development, and test results are reported for an experimental PPM focused, traveling-wave tube that produces 235 watts of CW RF power over 85 MHz centered at 12.080 GHz. The tube uses a coupled cavity RF circuit with a velocity taper for greater than 30 percent basic efficiency. Overall efficiency of 51 percent is achieved by means of a nine stage depressed collector designed at NASA Lewis Research Center. This collector is cooled by direct radiation to deep space.

Re-use of Low Bandwidth Equipment for High Bit Rate Transmission Using Signal Slicing Technique

DEFF Research Database (Denmark)

Wagner, Christoph; Spolitis, S.; Vegas Olmos, Juan José

: Massive fiber-to-the-home network deployment requires never ending equipment upgrades operating at higher bandwidth. We show effective signal slicing method, which can reuse low bandwidth opto-electronical components for optical communications at higher bit rates.......: Massive fiber-to-the-home network deployment requires never ending equipment upgrades operating at higher bandwidth. We show effective signal slicing method, which can reuse low bandwidth opto-electronical components for optical communications at higher bit rates....

Analysing IEEE 802.15.3c protocol in Fi-Wi hybrid networks

NARCIS (Netherlands)

Venkatesha Prasad, R.; Bien, Q.; Chandra, Kishor; Xueli, A.; Niemegeers, I.G.M.M.; Huong, N.

2013-01-01

Even though 60 GHz frequency band has limited coverage, due to the availability of higher bandwidth worldwide (unlicensed, approximately 5 GHz between 57-62 GHz), it is one of the promising candidates for future broadband employing both Fiber and Wireless (Fi-Wi) technology. In this article we

The EUMETSAT OSI SAF near 50 GHz sea ice emissivity model

Directory of Open Access Journals (Sweden)

Rasums T. Tonboe

2013-02-01

Full Text Available A sea ice thermal microwave emission model for 50 GHz was developed under EUMETSAT's Ocean and Sea Ice Satellite Application Facility (OSI SAF programme. The model is based on correlations between the surface brightness temperature at 18, 36 and 50 GHz. The model coefficients are estimated using simulated data from a combined thermodynamic and emission model. The intention with the model is to provide a first guess sea ice surface emissivity estimate for atmospheric temperature sounding applications in the troposphere in numerical weather prediction (NWP models assimilating Advanced Microwave Sounding Unit (AMSU and Special Sensor Microwave Imager/Sounder (SSMIS data. The spectral gradient ratio is defined as the difference over the sum of the SSMIS brightness temperatures at 18 and 36 GHz vertical linear polarisation (GR1836. The GR1836 is related to the emissivity at the atmospheric temperature sounding channels at around 50 GHz. Furthermore, the brightness temperatures and the polarisation ratio (PR at the neighbouring 18, 36 and 50 GHz channels are highly correlated. Both the gradient ratio at 18 and 36 GHz and the PR at 36 GHz measured by SSMIS are input into the model predicting the 50 GHz emissivity for horizontal and vertical linear polarisations and incidence angles between 0° and 60° The simulated emissivity is compared to the emissivity derived with alternative methods. The fit to real AMSU observations is investigated using the different emissivity estimates for simulating the observations with atmospheric data from a regional weather prediction model.

High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)

Science.gov (United States)

Lin, Chun-Han; Tu, Charng-Gan; Yao, Yu-Feng; Chen, Sheng-Hung; Su, Chia-Ying; Chen, Hao-Tsung; Kiang, Yean-Woei; Yang, Chih-Chung

2017-02-01

Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than 0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

Raman scheme for adjustable-bandwidth quantum memory

International Nuclear Information System (INIS)

Le Goueet, J.-L.; Berman, P. R.

2009-01-01

We propose a scenario of quantum memory for light based on Raman scattering. The storage medium is a vapor and the different spectral components of the input pulse are stored in different atomic velocity classes. One uses appropriate pulses to reverse the resulting Doppler phase shift and to regenerate the input pulse, without distortion, in the backward direction. The different stages of the protocol are detailed and the recovery efficiency is calculated in the semiclassical picture. Since the memory bandwidth is determined by the Raman transition Doppler width, it can be adjusted by changing the angle between the input pulse wave vector and the control beams. The optical depth also depends on the beam angle. As a consequence the available optical depth can be optimized depending on the needed bandwidth. The predicted recovery efficiency is close to 100% for large optical depth.

Gain-switched all-fiber laser with narrow bandwidth

DEFF Research Database (Denmark)

Larsen, Casper; Giesberts, M.; Nyga, S.

2013-01-01

pulse energy is 20 μJ in a duration of 135 ns at 7 kHz. The bandwidth increases for a higher pump pulse energy and repetition rate, and this sets the limit of the output pulse energy. A single power amplifier is added to raise the peak power to the kW-level and the pulse energy to 230 μJ while keeping......Gain-switching of a CW fiber laser is a simple and cost-effective approach to generate pulses using an all-fiber system. We report on the construction of a narrow bandwidth (below 0.1 nm) gain-switched fiber laser and optimize the pulse energy and pulse duration under this constraint. The extracted...

Multi-band microwave photonic satellite repeater scheme employing intensity Mach-Zehnder modulators

Institute of Scientific and Technical Information of China (English)

Yin Jie; Dong Tao; Zhang Bin; Hao Yan; Cao Guixing; Cheng Zijing; Xu Kun; Zhou Yue; Dai Jian

2017-01-01

To solve the satellite repeater's flexible and wideband frequency conversion problem,we propose a novel microwave photonic repeater system,which can convert the upload signal's carrier to six different frequencies.The scheme employs one 20 GHz bandwidth dual-drive Mach-Zehnder modulator (MZM) and two 10 GHz bandwidth MZMs.The basic principle of this scheme is filtering out two optical sidebands after the optical carrier suppression (OCS) modulation and combining two sidebands modulated by the input radio frequency (RF) signal.This structure can realize simultaneous multi-band frequency conversion with only one frequency-fixed microwave source and prevent generating harmful interference sidebands by using two corresponding optical filters after optical modulation.In the simulation,one C-band signal of 6 GHz carrier can be successfully converted to 12 GHz (Ku-band),28 GHz,34 GHz,40 GHz,46 GHz (Ka-band) and 52 GHz (V-band),which can be an attractive method to realize multi-band microwave photonic satellite repeater.Alternatively,the scheme can be configured to generate multi-band local oscillators (LOs) for widely satellite onboard clock distribution when the input RF signal is replaced by the internal clock source.

77 FR 48097 - Operation of Radar Systems in the 76-77 GHz Band

Science.gov (United States)

2012-08-13

... modify the emission limits for vehicular radar systems operating within the 76-77 GHz band. Specifically.... 15.253 of the rules for vehicular radar systems operating in the 76-77 GHz band. Vehicular radars can... sensors operating in the 76-77 GHz band, the spectrum shall be investigated up to 231 GHz. (f) Fundamental...

Wireless hydrotherapy smart suit for monitoring handicapped people

Science.gov (United States)

Correia, Jose H.; Mendes, Paulo M.

2005-02-01

This paper presents a smart suit, water impermeable, containing sensors and electronics for monitoring handicapped people at hydrotherapy sessions in swimming-pools. For integration into textiles, electronic components should be designed in a functional, robust and inexpensive way. Therefore, small-size electronics microsystems are a promising approach. The smart suit allows the monitoring of individual biometric data, such as heart rate, temperature and movement of the body. Two solutions for transmitting the data wirelessly are presented: through a low-voltage (3.0 V), low-power, CMOS RF IC (1.6 mm x 1.5 mm size dimensions) operating at 433 MHz, with ASK modulation and a patch antenna built on lossy substrates compatible with integrated circuits fabrication. Two different substrates were used for antenna implementation: high-resistivity silicon (HRS) and Corning Pyrex #7740 glass. The antenna prototypes were built to operate close to the 5 GHz ISM band. They operate at a center frequency of 5.705 GHz (HRS) and 5.995 GHz (Pyrex). The studied parameters were: substrate thickness, substrate losses, oxide thickness, metal conductivity and thickness. The antenna on HRS uses an area of 8 mm2, providing a 90 MHz bandwidth and ~0.3 dBi of gain. On a glass substrate, the antenna uses 12 mm2, provides 100 MHz bandwidth and ~3 dBi of gain.

47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

Science.gov (United States)

2010-10-01

... exceed 3000 microvolts/meter/MHz at 3 meters in any direction. Further, an AVIS, when in its operating position, shall not produce a field strength greater than 400 microvolts/meter/MHz at 3 meters in any... maximum of 100 microvolts/meter/MHz at 3 meters, measured from 30 MHz to 20 GHz for the complete system...

Towards low-cost gigabit wireless systems at 60 GHz

NARCIS (Netherlands)

Yang, Haibing

2008-01-01

The world-wide availability of the huge amount of license-free spectral space in the 60 GHz band provides wide room for gigabit-per-second (Gb/s) wireless applications. A commercial (read: low-cost) 60-GHz transceiver will, however, provide limited system performance due to the stringent link budget

Composeable Chat over Low-Bandwidth Intermittent Communication Links

National Research Council Canada - National Science Library

Wilcox, D. R

2007-01-01

Intermittent low-bandwidth communication environments, such as those encountered in U.S. Navy tactical radio and satellite links, have special requirements that do not pertain to commercial applications...

Bandwidth tunable amplifier for recording biopotential signals.

Science.gov (United States)

Hwang, Sungkil; Aninakwa, Kofi; Sonkusale, Sameer

2010-01-01

This paper presents a low noise, low power, bandwidth tunable amplifier for bio-potential signal recording applications. By employing depletion-mode pMOS transistor in diode configuration as a tunable sub pA current source to adjust the resistivity of MOS-Bipolar pseudo-resistor, the bandwidth is adjusted without any need for a separate band-pass filter stage. For high CMRR, PSRR and dynamic range, a fully differential structure is used in the design of the amplifier. The amplifier achieves a midband gain of 39.8dB with a tunable high-pass cutoff frequency ranging from 0.1Hz to 300Hz. The amplifier is fabricated in 0.18εm CMOS process and occupies 0.14mm(2) of chip area. A three electrode ECG measurement is performed using the proposed amplifier to show its feasibility for low power, compact wearable ECG monitoring application.

Multiparty quantum secret sharing based on GHZ states

Energy Technology Data Exchange (ETDEWEB)

Hwang, Tzonelih; Hwang, Cheng-Chieh [Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, 701 Taiwan (China); Li, Chuan-Ming, E-mail: hwangtl@ismail.csie.ncku.edu.tw [Department of Information Management, Shu-Zen College of Medicine and Management, Kaohsiung, 821 Taiwan (China)

2011-04-15

Gao (2009 Commun. Theor. Phys. 52 421-4) has proposed an efficient multiparty quantum secret sharing (MQSS) with two-photon three-dimensional Einstein-Podolsky-Rosen (EPR) pairs. This work shows that a similar idea can also be used to construct an MQSS using the Greenberger-Horne-Zeilinger (GHZ) states. Compared to other MQSSs using GHZ-related states, the newly proposed protocol is more efficient in the aspect of qubit utilization.

Interconnection Structures, Management and Routing Challenges in Cloud-Service Data Center Networks: A Survey

Directory of Open Access Journals (Sweden)

Ahmad Nahar Quttoum

2018-01-01

Full Text Available Today’s data center networks employ expensive networking equipments in associated structures that were not designed to meet the increasing requirements of the current large-scale data center services. Limitations that vary between reliability, resource utilization, and high costs are challenging. The era of cloud computing represents a promise to enable large-scale data centers. Computing platforms of such cloud service data centers consist of large number of commodity low-price servers that, with a theme of virtualization on top, can meet the performance of the expensive high-level servers at only a fraction of the price. Recently, the research in data center networks started to evolve rapidly. This opened the path for addressing many of its design and management challenges, these like scalability, reliability, bandwidth capacities, virtual machines’ migration, and cost. Bandwidth resource fragmentation limits the network agility, and leads to low utilization rates, not only for the bandwidth resources, but also for the servers that run the applications. With Traffic Engineering methods, managers of such networks can adapt for rapid changes in the network traffic among their servers, this can help to provide better resource utilization and lower costs. The market is going through exciting changes, and the need to run demanding-scale services drives the work toward cloud networks. These networks that are enabled by the notation of autonomic management, and the availability of commodity low-price network equipments. This work provides the readers with a survey that presents the management challenges, design and operational constraints of the cloud-service data center networks

Wideband pulse amplifier with 8 GHz GBW product in a 0.35 {mu}m CMOS technology for the integrated camera of the Cherenkov Telescope Array

Energy Technology Data Exchange (ETDEWEB)

Gascon, D; Sanuy, A; Ribo, M [Dept. AM i Dept.ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona, Marti i Franques 1, E08028, Barcelona (Spain); Delagnes, E; Glicenstein, J-F [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Sieiro, X [Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, E08028, Barcelona (Spain); Feinstein, F; Vorobiov, S [LPTA, Universite Montpellier II and IN2P3/CNRS, Montpellier (France); Nayman, P; Toussenel, F; Tavernet, J-P; Vincent, P, E-mail: gascon@ecm.ub.es [LPNHE, Universite Paris VI and IN2P3/CNRS, Paris (France)

2010-12-15

A fully differential wideband amplifier for the camera of the Cherenkov Telescope Array (CTA) is presented. This amplifier would be part of a new ASIC, developed by the NECTAr collaboration, performing the digitization at 1 GS/s with a dynamic range of 16 bits. Input amplifiers must have a voltage gain up to 20 V/V and a bandwidth of 400 MHz. Being impossible to design a fully differential operational amplifier with an 8 GHz GBW product in a 0.35{mu}m CMOS technology, an alternative implementation based on HF linearised transconductors is explored. Test results show that the required GBW product is achieved, with a linearity error smaller than 1% for a differential output voltage range up to 1 Vpp, and smaller than 3% for 2 Vpp.

Wideband pulse amplifier with 8 GHz GBW product in a 0.35 μm CMOS technology for the integrated camera of the Cherenkov Telescope Array

International Nuclear Information System (INIS)

Gascon, D; Sanuy, A; Ribo, M; Delagnes, E; Glicenstein, J-F; Sieiro, X; Feinstein, F; Vorobiov, S; Nayman, P; Toussenel, F; Tavernet, J-P; Vincent, P

2010-01-01

A fully differential wideband amplifier for the camera of the Cherenkov Telescope Array (CTA) is presented. This amplifier would be part of a new ASIC, developed by the NECTAr collaboration, performing the digitization at 1 GS/s with a dynamic range of 16 bits. Input amplifiers must have a voltage gain up to 20 V/V and a bandwidth of 400 MHz. Being impossible to design a fully differential operational amplifier with an 8 GHz GBW product in a 0.35μm CMOS technology, an alternative implementation based on HF linearised transconductors is explored. Test results show that the required GBW product is achieved, with a linearity error smaller than 1% for a differential output voltage range up to 1 Vpp, and smaller than 3% for 2 Vpp.

Broadband analog to digital conversion with spatial-spectral holography

International Nuclear Information System (INIS)

Babbitt, W. Randall; Neifeld, Mark A.; Merkel, Kristian D.

2007-01-01

A new approach to broadband photonic-assisted analog-to-digital converter (ADC) technology is proposed and analyzed. The core of the device is a spatial spectral holographic (SSH) material, which can directly record the signals of interest in the frequency domain. An SSH-ADC acts as a frequency-domain stretch processor, which leverages the high performance of conventional ADCs by converting high bandwidth input signals to low bandwidth output signals without loss of information. Analysis of a 10 GHz bandwidth SSH-ADC predicts that 10-bit performance can be achieved with currently available materials and components. SSH-ADC technology is scalable to bandwidths over 100 GHz with recently developed SSH materials. While the SSH-ADC is a transient digitizer, the spatial parallelism of SSH materials can be utilized to enable continuous digitization

Broadband analog to digital conversion with spatial-spectral holography

Energy Technology Data Exchange (ETDEWEB)

Babbitt, W. Randall [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States)]. E-mail: babbitt@physics.montana.edu; Neifeld, Mark A. [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States); Merkel, Kristian D. [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States)

2007-11-15

A new approach to broadband photonic-assisted analog-to-digital converter (ADC) technology is proposed and analyzed. The core of the device is a spatial spectral holographic (SSH) material, which can directly record the signals of interest in the frequency domain. An SSH-ADC acts as a frequency-domain stretch processor, which leverages the high performance of conventional ADCs by converting high bandwidth input signals to low bandwidth output signals without loss of information. Analysis of a 10 GHz bandwidth SSH-ADC predicts that 10-bit performance can be achieved with currently available materials and components. SSH-ADC technology is scalable to bandwidths over 100 GHz with recently developed SSH materials. While the SSH-ADC is a transient digitizer, the spatial parallelism of SSH materials can be utilized to enable continuous digitization.

THz Tube Waveguides With Low Loss, Low Dispersion, and High Bandwidth

DEFF Research Database (Denmark)

Bao, Hualong; Nielsen, Kristian; Bang, Ole

2014-01-01

We propose, model and experimentally characterize a novel class of terahertz hollow-core tube waveguides with high-loss cladding material, resulting in propagation with low loss, low dispersion, and high useful bandwidth.......We propose, model and experimentally characterize a novel class of terahertz hollow-core tube waveguides with high-loss cladding material, resulting in propagation with low loss, low dispersion, and high useful bandwidth....

Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

Science.gov (United States)

Sharma, Manish; Awasthi, Y. K.; Singh, Himanshu; Kumar, Raj; Kumari, Sarita

2016-11-01

In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04-3.68 GHz) & WLAN (4.73-5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83-14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8-12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

Compact Dual-Band Dipole Antenna with Asymmetric Arms for WLAN Applications

Directory of Open Access Journals (Sweden)

Chung-Hsiu Chiu

2014-01-01

Full Text Available A dual-band dipole antenna that consists of a horn- and a C-shaped metallic arm is presented. Depending on the asymmetric arms, the antenna provides two −10 dB impedance bandwidths of 225 MHz (about 9.2% at 2.45 GHz and 1190 MHz (about 21.6% at 5.5 GHz, respectively. This feature enables it to cover the required bandwidths for wireless local area network (WLAN operation at the 2.4 GHz band and 5.2/5.8 GHz bands for IEEE 802.11 a/b/g standards. More importantly, the compact size (7 mm × 24 mm and good radiating performance of the antenna are profitable to be integrated with wireless communication devices on restricted RF-elements spaces.

Improved space bandwidth product in image upconversion

DEFF Research Database (Denmark)

Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

2012-01-01

We present a technique increasing the space bandwidth product of a nonlinear image upconversion process used for spectral imaging. The technique exploits the strong dependency of the phase-matching condition in sum frequency generation (SFG) on the angle of propagation of the interacting fields...

Design of a 17.14 GHz quasi-optical pulse compressor

International Nuclear Information System (INIS)

Petelin, M. I.; Kuzikov, S. V.; Danilov, Yu. Yu.; Granatstein, V. L.; Nusinovich, G. S.

1999-01-01

A quasi-optical version of the ring cavity pulse compressor is considered. This concept is based on the coupling of the input wave to a whispering gallery mode of a barrel-like cavity due to helical corrugations of the cavity wall. Low-power tests of the prototype were carried out at 11.4 GHz and demonstrated reasonable agree-ment between experimental data and theoretical predictions. The design of a similar pulse compressor at 17.14 GHz compatible with the 17.14 GHz, 100 MW gyroklystron currently under development at the University of Maryland is presented

Sb-Based Double Heterojunction Bipolar Transistors (DHBTs) With Fmax 650GHz for 340GHz Transmitter

Science.gov (United States)

2008-12-01

PROPER IDENTIFICATION . NOT TO BE USED FOR INTERIM PROGRESS REPORTS SEE PAGE 2 FOR INTERIM PROGRESS REPORT INSTRUCTIONS MEMORANDUM OF TRANSMITTAL...conduction band lineup . These advantages have led to rapid progress in increasing device bandwidths, allowing competitive RF performance with established

THE IMPROVEMENT OF COMPUTER NETWORK PERFORMANCE WITH BANDWIDTH MANAGEMENT IN KEMURNIAN II SENIOR HIGH SCHOOL

Directory of Open Access Journals (Sweden)

Bayu Kanigoro

2012-05-01

Full Text Available This research describes the improvement of computer network performance with bandwidth management in Kemurnian II Senior High School. The main issue of this research is the absence of bandwidth division on computer, which makes user who is downloading data, the provided bandwidth will be absorbed by the user. It leads other users do not get the bandwidth. Besides that, it has been done IP address division on each room, such as computer, teacher and administration room for supporting learning process in Kemurnian II Senior High School, so wireless network is needed. The method is location observation and interview with related parties in Kemurnian II Senior High School, the network analysis has run and designed a new topology network including the wireless network along with its configuration and separation bandwidth on microtic router and its limitation. The result is network traffic on Kemurnian II Senior High School can be shared evenly to each user; IX and IIX traffic are separated, which improve the speed on network access at school and the implementation of wireless network.Keywords: Bandwidth Management; Wireless Network

Composite GPS Patch Antenna for the AR Bandwidth Enhancement

Directory of Open Access Journals (Sweden)

Minkil Park

2016-01-01

Full Text Available A composite Global Positioning System (GPS patch antenna with a quadrature 3 dB hybrid coupler was designed and implemented for working RHCP and had a broadband axial ratio (AR bandwidth. We designed two patches as a FR-4 patch and 1.5 mm thickness thin ceramic patch with a quadrature 3 dB hybrid coupler. A CP radiation pattern was achieved, and the AR bandwidth improved by incorporating a quadrature 3 dB hybrid coupler feed structure in a micro-strip patch antenna. SMD by chip elements was applied to the quadrature 3 dB hybrid coupler. For the composite FR-4 and ceramic patch antennas, the VSWR measurement showed a 2 : 1 ratio over the entire design band, and the 3 dB AR bandwidth was 295 and 580 MHz for the FR-4 patch and ceramic patch antennas, respectively. The antenna gains for the composite FR-4 and ceramic patch antennas were measured as 1.36–2.75 and 1.47–2.71 dBi with 15.11–25.3% and 19.25–28.45% efficiency, respectively.

A Bandwidth-Optimized Multi-Core Architecture for Irregular Applications

Energy Technology Data Exchange (ETDEWEB)

Secchi, Simone; Tumeo, Antonino; Villa, Oreste

2012-05-31

This paper presents an architecture template for next-generation high performance computing systems specifically targeted to irregular applications. We start our work by considering that future generation interconnection and memory bandwidth full-system numbers are expected to grow by a factor of 10. In order to keep up with such a communication capacity, while still resorting to fine-grained multithreading as the main way to tolerate unpredictable memory access latencies of irregular applications, we show how overall performance scaling can benefit from the multi-core paradigm. At the same time, we also show how such an architecture template must be coupled with specific techniques in order to optimize bandwidth utilization and achieve the maximum scalability. We propose a technique based on memory references aggregation, together with the related hardware implementation, as one of such optimization techniques. We explore the proposed architecture template by focusing on the Cray XMT architecture and, using a dedicated simulation infrastructure, validate the performance of our template with two typical irregular applications. Our experimental results prove the benefits provided by both the multi-core approach and the bandwidth optimization reference aggregation technique.

The 1.4 GHZ light curve of GRB 970508

NARCIS (Netherlands)

Galama, TJ; Wijers, RAMJ; Groot, PJ; Strom, RG; De Bruyn, AG; Kouveliotou, C; Robinson, CR; van Paradus, J

1998-01-01

We report on Westerbork 1.4 GHz radio observations of the radio counterpart to gamma-ray burst GRB 970508, between 0.80 and 138 days after this event. The 1.4 GHz light curve shows a transition from optically thick to thin emission between 39 and 54 days after the event. We derive the slope p of the

Compact Single-Layer Traveling-Wave Antenna DesignUsing Metamaterial Transmission Lines

Science.gov (United States)

Alibakhshikenari, Mohammad; Virdee, Bal Singh; Limiti, Ernesto

2017-12-01

This paper presents a single-layer traveling-wave antenna (TWA) that is based on composite right/left-handed (CRLH)-metamaterial (MTM) transmission line (TL) structure, which is implemented by using a combination of interdigital capacitors and dual-spiral inductive slots. By embedding dual-spiral inductive slots inside the CRLH MTM-TL results in a compact TWA. Dimensions of the proposed CRLH MTM-TL TWA is 21.5 × 30.0 mm2 or 0.372λ0 × 0.520λ0 at 5.2 GHz (center frequency). The fabricated TWA operates over 1.8-8.6 GHz with a fractional bandwidth greater than 120%, and it exhibits a peak gain and radiation efficiency of 4.2 dBi and 81%, respectively, at 5 GHz. By avoiding the use of lumped components, via-holes or defected ground structures, the proposed TWA design is economic for mass production as well as easy to integrate with wireless communication systems.

Extending the Peak Bandwidth of Parameters for Softmax Selection in Reinforcement Learning.

Science.gov (United States)

Iwata, Kazunori

2016-05-11

Softmax selection is one of the most popular methods for action selection in reinforcement learning. Although various recently proposed methods may be more effective with full parameter tuning, implementing a complicated method that requires the tuning of many parameters can be difficult. Thus, softmax selection is still worth revisiting, considering the cost savings of its implementation and tuning. In fact, this method works adequately in practice with only one parameter appropriately set for the environment. The aim of this paper is to improve the variable setting of this method to extend the bandwidth of good parameters, thereby reducing the cost of implementation and parameter tuning. To achieve this, we take advantage of the asymptotic equipartition property in a Markov decision process to extend the peak bandwidth of softmax selection. Using a variety of episodic tasks, we show that our setting is effective in extending the bandwidth and that it yields a better policy in terms of stability. The bandwidth is quantitatively assessed in a series of statistical tests.

Estimating Bandwidth Requirements using Flow-level Measurements

NARCIS (Netherlands)

Bruyère, P.; de Oliveira Schmidt, R.; Sperotto, Anna; Sadre, R.; Pras, Aiko

Bandwidth provisioning is an important task of network management and it is done aiming to meet desired levels of quality of service. Current practices of provisioning are mostly based on rules-of-thumb and use coarse traffic measurements that may lead to problems of under and over dimensioning of

Design of a Combined Beacon Receiver and Digital Radiometer for 40 GHz Propagation Measurements at the Madrid Deep Space Communications Complex

Science.gov (United States)

Zemba, Michael; Nessel, James; Morabito, David

2017-01-01

NASA Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL) have jointly developed an atmospheric propagation terminal to measure and characterize propagation phenomena at 40 GHz at the Madrid Deep Space Communications Complex (MDSCC) in Robledo de Chavela, Spain. The hybrid Q-band system utilizes a novel design which combines a 40 GHz beacon receiver and digital radiometer into the same RF front-end and observes the 39.402 GHz beacon of the European Space Agencys Alphasat Aldo Paraboni TDP5 experiment. Atmospheric measurements include gaseous absorption, rain fade, and scintillation. The radiometric measurement is calibrated by means of an included noise diode as well as tipping calibration. The goals of these measurements are to assist MDSCC mission operations as the facility increasingly supports Ka-band missions, as well as to contribute to the development and improvement of International Telecommunications Union (ITU) models for prediction of communications systems performance within the Q-band through the Aldo Paraboni Experiment. Herein, we provide an overview of the system design, characterization, and plan of operations which commenced at the MDSCC beginning in March 2017.

Icecube: Spaceflight Validation of an 874-GHz Submillimeter Wave Radiometer for Ice Cloud Remote Sensing

Science.gov (United States)

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

HIGH RESOLUTION 36 GHz IMAGING OF THE SUPERNOVA REMNANT OF SN 1987A

International Nuclear Information System (INIS)

Potter, T. M.; Staveley-Smith, L.; Zanardo, G.; Ng, C.-Y.; Gaensler, B. M.; Ball, Lewis; Kesteven, M. J.; Manchester, R. N.; Tzioumis, A. K.

2009-01-01

The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend the frequency range of an ongoing monitoring and imaging program conducted between 1.4 and 20 GHz. Our 36.2 GHz images have a diffraction-limited angular resolution of 0.''3-0.''4, which covers the gap between high resolution, low dynamic range VLBI images of the remnant and low resolution, high dynamic range images at frequencies between 1 and 20 GHz. The radio morphology of the remnant at 36 GHz is an elliptical ring with enhanced emission on the eastern and western sides, similar to that seen previously at lower frequencies. Model fits to the data in the Fourier domain show that the emitting region is consistent with a thick inclined torus of mean radius 0.''85, and a 2008 October flux density of 27 ± 6 mJy at 36.2 GHz. The spectral index for the remnant at this epoch, determined between 1.4 GHz and 36.2 GHz, is α = -0.83. There is tentative evidence for an unresolved central source with flatter spectral index.

Parametric Study of Micro Strip Patch Antenna Using Different Feeding Techniques for Wireless and Medical Applications

Directory of Open Access Journals (Sweden)

Debajyoti Chatterjee

2018-01-01

Full Text Available Due to the increasing bandwidth requirement of modern wireless communication systems, developing antenna having wider bandwidth have been receiving significant attention in the recent years. In this paper, a comparative analysis of the contacting feed (micro strip line and coaxial probe and non-contacting feed mechanism (both Aperture Coupling and Proximity Coupling in micro strip patch antenna has been done. In case of contacting feed, RF power is fed directly to the radiating patch using a connecting element such as a micro strip line whereas in case of non-contacting feeds, electromagnetic field coupling is done to transfer power between the micro strip line and the radiating patch. As per the latest research, ultra wide band technology is used in the frequency range from 3 GHz to 10 GHz. We have analyzed and compared the return loss and corresponding bandwidth of these four types of antenna at 5.853GHz so that this antenna may be used in medical as well as wireless applications.

A Directional Antenna in a Matching Liquid for Microwave Radar Imaging

Directory of Open Access Journals (Sweden)

Saeed I. Latif

2015-01-01

Full Text Available The detailed design equations and antenna parameters for a directional antenna for breast imaging are presented in this paper. The antenna was designed so that it could be immersed in canola oil to achieve efficient coupling of the electromagnetic energy to the breast tissue. Ridges were used in the horn antenna to increase the operating bandwidth. The antenna has an exponentially tapered section for impedance matching. The double-ridged horn antenna has a wideband performance from 1.5 GHz to 5 GHz (3.75 GHz or 110% of impedance bandwidth, which is suitable for breast microwave radar imaging. The fabricated antenna was tested and compared with simulated results, and similar bandwidths were obtained. Experiments were conducted on breast phantoms using these antennas, to detect a simulated breast lesion. The reconstructed image from the experiments shows distinguishable tumor responses indicating promising results for successful breast cancer detection.

Studies of bandwidth dependence of laser plasma instabilities driven by the Nike laser

Science.gov (United States)

Weaver, J.; Kehne, D.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Oh, J.; Lehmberg, R. H.; Brown, C. M.; Seely, J.; Feldman, U.

2012-10-01

Experiments at the Nike laser facility of the Naval Research Laboratory are exploring the influence of laser bandwidth on laser plasma instabilities (LPI) driven by a deep ultraviolet pump (248 nm) that incorporates beam smoothing by induced spatial incoherence (ISI). In early ISI studies with longer wavelength Nd:glass lasers (1054 nm and 527 nm),footnotetextObenschain, PRL 62(1989);Mostovych, PRL 62(1987);Peyser, Phys. Fluids B 3(1991). stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν/ν˜0.03-0.19%) pulses irradiated targets at moderate to high intensities (10^14-10^15 W/cm^2). The current studies will compare the emission signatures of LPI from planar CH targets during Nike operation at large bandwidth (δν˜1THz) to observations for narrower bandwidth operation (δν˜0.1-0.3THz). These studies will help clarify the relative importance of the short wavelength and wide bandwidth to the increased LPI intensity thresholds observed at Nike. New pulse shapes are being used to generate plasmas with larger electron density scale-lengths that are closer to conditions during pellet implosions for direct drive inertial confinement fusion.

The microwave absorbing properties of ZnO/Fe3O4/paraffin composites in low frequency band

Science.gov (United States)

Yin, Pengfei; Deng, Yu; Zhang, Limin; Huang, Juan; Li, Huayao; Li, Youhongyu; Qi, Yali; Tao, Yu

2018-02-01

ZnO/Fe3O4/paraffin composites with good microwave absorption performance in low frequency band were prepared by physical blending technology. The morphology, phase structures, frequency-dependent electromagnetic and microwave absorbing properties of the composites were investigated. The results showed that the addition content of ZnO can adjust the microwave absorbing properties i.e. the position, intensity, and absorption bandwidth of composites, and the synergetic consequence of dielectric loss and magnetic loss is the main microwave absorption mechanism of the composites. The bandwidths with RL below -10 dB over different frequency ranges were obtained in the low frequency range of 0.5 ˜ 3 GHz at a thickness of 5 mm, e.g. 0.93 GHz from 1.59 to 2.52 GHz and 0.85 GHz from 1.26 to 2.11 GHz corresponding to the mass ratios of ZnO and Fe3O4 are 1:2 and 1:4, respectively. Thus, such absorbers can be applied as effective microwave absorbers in low frequency range of 0.5 ˜ 3 GHz.

Handoff Management in Radio over Fiber 60 GHz Indoor Networks

NARCIS (Netherlands)

Bien, V.Q.

2014-01-01

Because of high data rate multimedia applications such as HD and UHDTV, online games, etc., the future home networks are expected to support short-range gigabit transmission. With the worldwide availability of 5 GHz spectrum at the 60 GHz band, it creates the opportunity for a promising air

System on Package (SoP) Millimeter Wave Filters for 5G Applications

KAUST Repository

Showail, Jameel

2018-05-01

Bandpass filters are an essential component of wireless communication systems that only transmits frequencies corresponding to the communication band and rejects all other frequencies. As the deployment of 5G draws nearer, first deployments are expected in 2020 [1], the need for viable filters at the new frequency bands becomes more imminent. Size and performance are two critical considerations for a filter that will be used in emerging mobile communication applications. The high frequency of 5G communication, 28 GHz as opposed to sub 6 GHz for nearly all previous communication protocols, means that previously utilized lumped component based solutions cannot be implemented since they are ill-suited for mm-wave applications. The focus of this work is the miniaturization of a high-performance filter. The Substrate Integrated Waveguide (SIW) is a high performance and promising structure and Low Temperature Co-Fired Ceramic (LTCC) is a high-performance material that both can operate at higher frequencies than the technologies used for previous telecommunication generations. To miniaturize the structure, a compact folded four-cavity SIW filter is designed, implemented and tested. The feeding structure is integrated into the filter to exploit the System on Package (SoP) attributes of LTCC and further reduce the total area of the filter individually and holistically when looking at the final integrated system. Two unique three dimensional (3D) integrated SoP LTCC two-stage SIW single cavity filters and one unique four-cavity filter all with embedded planar resonators are designed, fabricated and tested. The embedded resonators create a two-stage effect in a single cavity filter. The better single cavity design provides a 15% fractional bandwidth at a center frequency of 28.12 GHz, and with an insertion loss of -0.53 dB. The fabricated four-cavity filter has a 3-dB bandwidth of .98GHz centered at 27.465 GHz, and with an insertion loss of -2.66 dB. The designs presented

Results of RIKEN superconducting electron cyclotron resonance ion source with 28 GHz.

Science.gov (United States)

Higurashi, Y; Ohnishi, J; Nakagawa, T; Haba, H; Tamura, M; Aihara, T; Fujimaki, M; Komiyama, M; Uchiyama, A; Kamigaito, O

2012-02-01

We measured the beam intensity of highly charged heavy ions and x-ray heat load for RIKEN superconducting electron cyclotron resonance ion source with 28 GHz microwaves under the various conditions. The beam intensity of Xe(20+) became maximum at B(min) ∼ 0.65 T, which was ∼65% of the magnetic field strength of electron cyclotron resonance (B(ECR)) for 28 GHz microwaves. We observed that the heat load of x-ray increased with decreasing gas pressure and field gradient at resonance zone. It seems that the beam intensity of highly charged heavy ions with 28 GHz is higher than that with 18 GHz at same RF power.

Electron-beam buncher to operate over the frequency range 1-4 GHz

International Nuclear Information System (INIS)

Goldberg, D.A.; Arthur, A.A.; Flood, W.S.; Voelker, F.

1983-03-01

We present a description of an electron buncher to be installed in the terminal of a Van de Graaff, which is to produce a modulated beam over the frequency range 1-4 GHz. The modulator geometry has been optimized so that the modulation amplitude should be nearly constant over the frequency ranges 1-2 GHz and 2-4 GHz. Preliminary results indicate the device works as predicted

GHz Yb:KYW oscillators in time-resolved spectroscopy

Science.gov (United States)

Li, Changxiu; Krauß, Nico; Schäfer, Gerhard; Ebner, Lukas; Kliebisch, Oliver; Schmidt, Johannes; Winnerl, Stephan; Hettich, Mike; Dekorsy, Thomas

2018-02-01

A high-speed asynchronous optical sampling system (ASOPS) based on Yb:KYW oscillators with 1-GHz repetition rate is reported. Two frequency-offset-stabilized diode-pumped Yb:KYW oscillators are employed as pump and probe source, respectively. The temporal resolution of this system within 1-ns time window is limited to 500 fs and the noise floor around 10-6 (ΔR/R) close to the shot-noise level is obtained within an acquisition time of a few seconds. Coherent acoustic phonons are investigated by measuring multilayer semiconductor structures with multiple quantum wells and aluminum/silicon membranes in this ASOPS system. A wavepacket-like phonon sequence at 360 GHz range is detected in the semiconductor structures and a decaying sequence of acoustic oscillations up to 200 GHz is obtained in the aluminum/silicon membranes. Coherent acoustic phonons generated from semiconductor structures are further manipulated by a double pump scheme through pump time delay control.

Hybrid Online Labs: Making Remote Laboratories Usable Under Unfavorable Bandwidth Conditions

OpenAIRE

Kayode Peter Ayodele; Lawrence O. Kehinde; Olusola A. Komolafe

2012-01-01

One of few limitations of remote laboratory technology is the fact that access and usability of such laboratories depend largely on the existence of favorable bandwidth conditions between the remote user and the system under test. This dependence is regrettable because some of the institutions likely to find remote laboratories attractive are also those most likely to have severe bandwidth limitations. Also, a typical remote laboratory will be completely unusable to remote students in the eve...

Supernova SN 2008iz in M82 Galaxy

African Journals Online (AJOL)

kagoyire

models to the data, a simple power-law model and a simplified Weiler model, yielding a decline index, β = -1.23±0.01 and ... (4.8 GHz), X (8.4 GHz), K (22.3 GHz) and Q-bands (43.2 GHz) to trace the evolution of the radio ... with a total bandwidth of 128 MHz, each in dual circular polarization. The flux calibrator 3C48 was ...

Implementation and Investigation of a Compact Circular Wide Slot UWB Antenna with Dual Notched Band Characteristics using Stepped Impedance Resonators

Directory of Open Access Journals (Sweden)

Yingsong Li

2012-04-01

Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz and 8.0 GHz - 9.3 GHz for satellite and military applications.

CIRCULARLY POLARIZED SLOT ANTENNA WITH COMPACT SIZE FOR WLAN/WIMAX APPLICATION

Directory of Open Access Journals (Sweden)

Azim Rezaei Motlagh

2014-01-01

Full Text Available In this letter a circle patch that have two slots in ground and patch is presented. The antenna is operated in WLAN/WiMAX at 4.7~6 GHz. The 3dB axial ratio bandwidth is 0.5GHz at 5.3~5.8GHz. Comparison results between measured and simulated of antenna are acceptable.

A CMOS frequency generation module for 60-GHz applications

International Nuclear Information System (INIS)

Zhou Chunyuan; Zhang Lei; Wang Hongrui; Qian He

2012-01-01

A frequency generation module for 60-GHz transceivers and phased array systems is presented in this paper. It is composed of a divide-by-2 current mode logic divider (CML) and a doubler in push-push configuration. Benefiting from the CML structure and push-push configuration, the proposed frequency generation module has a wide operating frequency range to cover process, voltage, and temperature variation. It is implemented in a 90-nm CMOS process, and occupies a chip area of 0.64 × 0.65 mm 2 including pads. The measurement results show that the designed frequency generation module functions properly with input frequency over 15 GHz to 25 GHz. The whole chip dissipates 12.1 mW from a 1.2-V supply excluding the output buffers. (semiconductor integrated circuits)

Half-cycle QAM modulation for VCSEL-based optical links

DEFF Research Database (Denmark)

Pham, Tien Thang; Rodes Lopez, Roberto; Jensen, Jesper Bevensee

2012-01-01

Abstract (40-Word Limit): Novel spectrally efficient half-cycle QAM modulation is experimentally demonstrated. 10 Gbps 4-QAM signal in 7.5-GHz bandwidth was successfully transmitted over 20 km SMF using an un-cooled 1.5 µm VCSEL with no equalization applied.......Abstract (40-Word Limit): Novel spectrally efficient half-cycle QAM modulation is experimentally demonstrated. 10 Gbps 4-QAM signal in 7.5-GHz bandwidth was successfully transmitted over 20 km SMF using an un-cooled 1.5 µm VCSEL with no equalization applied....

A high control bandwidth design method for aalborg inverter under weak grid condition

DEFF Research Database (Denmark)

Wu, Weimin; Zhou, Cong; Wang, Houqin

2017-01-01

Aalborg Inverter is a kind of high efficient Buck-Boost inverter. Since it may work in “Buck-Boost” mode, the control bandwidth should be high enough to ensure a good performance under any grid condition. However, during the “Boost” operation, the control bandwidth depends much on the grid...

Feasibility of automotive radar at frequencies beyond 100 GHz

OpenAIRE

Köhler, Mike; Hasch, Jürgen; Blöcher, Hans Ludwig; Schmidt, Lorenz-Peter

2014-01-01

Radar sensors are used widely in modern driver assistance systems. Available sensors nowadays often operate in the 77 GHz band and can accurately provide distance, velocity, and angle information about remote objects. Increasing the operation frequency allows improving the angular resolution and accuracy. In this paper, the technical feasibility to move the operation frequency beyond 100 GHz is discussed, by investigating dielectric properties of radome materials, the attenuation of rain and ...

Maximum Bandwidth Enhancement of Current Mirror using Series-Resistor and Dynamic Body Bias Technique

Directory of Open Access Journals (Sweden)

V. Niranjan

2014-09-01

Full Text Available This paper introduces a new approach for enhancing the bandwidth of a low voltage CMOS current mirror. The proposed approach is based on utilizing body effect in a MOS transistor by connecting its gate and bulk terminals together for signal input. This results in boosting the effective transconductance of MOS transistor along with reduction of the threshold voltage. The proposed approach does not affect the DC gain of the current mirror. We demonstrate that the proposed approach features compatibility with widely used series-resistor technique for enhancing the current mirror bandwidth and both techniques have been employed simultaneously for maximum bandwidth enhancement. An important consequence of using both techniques simultaneously is the reduction of the series-resistor value for achieving the same bandwidth. This reduction in value is very attractive because a smaller resistor results in smaller chip area and less noise. PSpice simulation results using 180 nm CMOS technology from TSMC are included to prove the unique results. The proposed current mirror operates at 1Volt consuming only 102 µW and maximum bandwidth extension ratio of 1.85 has been obtained using the proposed approach. Simulation results are in good agreement with analytical predictions.

High power, 140 GHz gyrotron

International Nuclear Information System (INIS)

Kreischer, K.E.; Temkin, R.J.; Mulligan, W.J.; MacCabe, S.; Chaplya, R.

1982-01-01

The design and construction of a pulsed 100 kW, 140 GHz gyrotron is described. Initial gyrotron operation is expected in early 1982. Advances in gyrotron theory have also been carried out in support of this experimental research. The application of gyrotrons to plasma diagnostics is also under investigation. (author)

Steganalysis and improvement of a quantum steganography protocol via a GHZ4 state

International Nuclear Information System (INIS)

Xu Shu-Jiang; Chen Xiu-Bo; Niu Xin-Xin; Yang Yi-Xian

2013-01-01

Quantum steganography that utilizes the quantum mechanical effect to achieve the purpose of information hiding is a popular topic of quantum information. Recently, El Allati et al. proposed a new quantum steganography using the GHZ 4 state. Since all of the 8 groups of unitary transformations used in the secret message encoding rule change the GHZ 4 state into 6 instead of 8 different quantum states when the global phase is not considered, we point out that a 2-bit instead of a 3-bit secret message can be encoded by one group of the given unitary transformations. To encode a 3-bit secret message by performing a group of unitary transformations on the GHZ 4 state, we give another 8 groups of unitary transformations that can change the GHZ 4 state into 8 different quantum states. Due to the symmetry of the GHZ 4 state, all the possible 16 groups of unitary transformations change the GHZ 4 state into 8 different quantum states, so the improved protocol achieves a high efficiency

37 GHz METHANOL MASERS : HORSEMEN OF THE APOCALYPSE FOR THE CLASS II METHANOL MASER PHASE?

International Nuclear Information System (INIS)

Ellingsen, S. P.; Breen, S. L.; Sobolev, A. M.; Voronkov, M. A.; Caswell, J. L.; Lo, N.

2011-01-01

We report the results of a search for class II methanol masers at 37.7, 38.3, and 38.5 GHz toward a sample of 70 high-mass star formation regions. We primarily searched toward regions known to show emission either from the 107 GHz class II methanol maser transition, or from the 6.035 GHz excited OH transition. We detected maser emission from 13 sources in the 37.7 GHz transition, eight of these being new detections. We detected maser emission from three sources in the 38 GHz transitions, one of which is a new detection. We find that 37.7 GHz methanol masers are only associated with the most luminous 6.7 and 12.2 GHz methanol maser sources, which in turn are hypothesized to be the oldest class II methanol sources. We suggest that the 37.7 GHz methanol masers are associated with a brief evolutionary phase (of 1000-4000 years) prior to the cessation of class II methanol maser activity in the associated high-mass star formation region.

IMPROVING BANDWIDTH OF FLIPPED VOLTAGE FOLLOWER USING GATE-BODY DRIVEN TECHNIQUE

Directory of Open Access Journals (Sweden)

VANDANA NIRANJAN

2017-01-01

Full Text Available In this paper, a new approach to enhance the bandwidth of flipped voltage follower is explored. The proposed approach is based on gate-body driven technique. This technique boosts the transconductance in a MOS transistor as both gate and body/bulk terminals are tied together and used as signal input. This novel technique appears as a good solution to merge the advantages of gate-driven and bulk-driven techniques and suppress their disadvantages. The gate-body driven technique utilizes body effect to enable low voltage low power operation and improves the overall performance of flipped voltage follower, providing it with low output impedance, high input impedance and bandwidth extension ratio of 2.614. The most attractive feature is that bandwidth enhancement has been achieved without use of any passive component or extra circuitry. Simulations in PSpice environment for 180 nm CMOS technology verified the predicted theoretical results. The improved flipped voltage follower is particularly interesting for high frequency low noise signal processing applications.

24 GHz cmWave Radio Propagation Through Vegetation

DEFF Research Database (Denmark)

Rodriguez, Ignacio; Abreu, Renato Barbosa; Portela Lopes de Almeida, Erika

2016-01-01

This paper presents a measurement-based analysis of cm-wave radio propagation through vegetation at 24 GHz. A set of dedicated directional measurements were performed with horn antennas located close to street level inside a densely-vegetated area illuminated from above. The full azimuth was exam......This paper presents a measurement-based analysis of cm-wave radio propagation through vegetation at 24 GHz. A set of dedicated directional measurements were performed with horn antennas located close to street level inside a densely-vegetated area illuminated from above. The full azimuth...

Molecular astronomy using heterodyne detection at 691 GHz

International Nuclear Information System (INIS)

Fetterman, H.R.; Buhl, D.

1984-01-01

Observations of the CO J 6 - 5 transition at 691 GHz in new interstellar and planetary sources have been made. The heterodyne receiver uses an optically pumped laser local oscillator and a quasi-optical Schottky diode mixer, with measured noise temperatures consistently under 4000 K (double sideband). Continued improvements in system performance and antenna coupling have made possible the mapping of 691 GHz emission from W3, and the detection of CO J 5 - 6 absorption in the atmosphere of Venus. A detailed description of the instrumentation and recent observational data are provided. 14 references

Iterative Available Bandwidth Estimation for Mobile Transport Networks

DEFF Research Database (Denmark)

Ubeda Castellanos, Carlos; López Villa, Dimas; Teyeb, Oumer Mohammed

2007-01-01

Available bandwidth estimation has lately been proposed to be used for end-to-end resource management in existing and emerging mobile communication systems, whose transport networks could end up being the bottleneck rather than the air interface. Algorithms for admission control, handover...

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

Science.gov (United States)

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.

The Bandwidths of a Matrix. A Survey of Algorithms

Directory of Open Access Journals (Sweden)

Mafteiu-Scai Liviu Octavian

2014-12-01

Full Text Available The bandwidth, average bandwidth, envelope, profile and antibandwidth of the matrices have been the subjects of study for at least 45 years. These problems have generated considerable interest over the years because of them practical relevance in areas like: solving the system of equations, finite element methods, circuit design, hypertext layout, chemical kinetics, numerical geophysics etc. In this paper a brief description of these problems are made in terms of their definitions, followed by a comparative study of them, using both approaches: matrix geometry and graph theory. Time evolution of the corresponding algorithms as well as a short description of them are made. The work also contains concrete real applications for which a large part of presented algorithms were developed.

Multiband Split-Ring Resonator Based Planar Inverted-F Antenna for 5G Applications

Directory of Open Access Journals (Sweden)

Muhammad Kamran Ishfaq

2017-01-01

Full Text Available 5G, the fifth generation of wireless communications, is focusing on multiple frequency bands, such as 6 GHz, 10 GHz, 15 GHz, 28 GHz, and 38 GHz, to achieve high data rates up to 10 Gbps or more. The industry demands multiband antennas to cover these distant frequency bands, which is a task much more challenging. In this paper, we have designed a novel multiband split-ring resonator (SRR based planar inverted-F antenna (PIFA for 5G applications. It is composed of a PIFA, an inverted-L parasitic element, a rectangular shaped parasitic element, and a split-ring resonator (SRR etched on the top plate of the PIFA. The basic PIFA structure resonates at 6 GHz. An addition of a rectangular shaped parasitic element produces a resonance at 15 GHz. The introduction of a split-ring resonator produces a band notch at 8 GHz, and a resonance at 10 GHz, while the insertion of an inverted-L shaped parasitic element further enhances the impedance bandwidth in the 10 GHz band. The frequency bands covered, each with more than 1 GHz impedance bandwidth, are 6 GHz (5–7 GHz, 10 GHz (9–10.8 GHz, and 15 GHz (14-15 GHz, expected for inclusion in next-generation wireless communications, that is, 5G. The design is simulated using Ansys Electromagnetic Suite 17 simulation software package. The simulated and the measured results are compared and analyzed which are generally in good agreement.

Optical interconnect technologies for high-bandwidth ICT systems

Science.gov (United States)

Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

2016-03-01

The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

Scalability analysis methodology for passive optical interconnects in data center networks using PAM

Science.gov (United States)

Lin, R.; Szczerba, Krzysztof; Agrell, Erik; Wosinska, Lena; Tang, M.; Liu, D.; Chen, J.

2017-11-01

A framework is developed for modeling the fundamental impairments in optical datacenter interconnects, i.e., the power loss and the receiver noises. This framework makes it possible, to analyze the trade-offs between data rates, modulation order, and number of ports that can be supported in optical interconnect architectures, while guaranteeing that the required signal-to-noise ratios are satisfied. To the best of our knowledge, this important assessment methodology is not yet available. As a case study, the trade-offs are investigated for three coupler-based top-of-rack interconnect architectures, which suffer from serious insertion loss. The results show that using single-port transceivers with 10 GHz bandwidth, avalanche photodiode detectors, and quadratical pulse amplitude modulation, more than 500 ports can be supported.

A User-Centered Cooperative Information System for Medical Imaging Diagnosis.

Science.gov (United States)

Gomez, Enrique J.; Quiles, Jose A.; Sanz, Marcos F.; del Pozo, Francisco

1998-01-01

Presents a cooperative information system for remote medical imaging diagnosis. General computer-supported cooperative work (CSCW) problems addressed are definition of a procedure for the design of user-centered cooperative systems (conceptual level); and improvement of user feedback and optimization of the communication bandwidth in highly…

Megawatt Power Level 120 GHz Gyrotrons for ITER Start-Up

Energy Technology Data Exchange (ETDEWEB)

Choi, E M; Marchewka, C; Mastovsky, I; Shapiro, M A; Sirigiri, J R; Temkin, R J [MIT - Plasma Science and Fusion Center, NW16-186, 167 Albany Street, Cambridge, MA 02139 (United States)

2005-01-01

We report operation of a 110 GHz gyrotron with 1.67 MW of output power measured in short pulses (3{mu}s) at an efficiency of 42% in the TE{sub 22,6} mode. We also present a preliminary design of a 1 MW, 120 GHz gyrotron for ITER start-up with an efficiency greater than 50%.

Megawatt Power Level 120 GHz Gyrotrons for ITER Start-Up

International Nuclear Information System (INIS)

Choi, E M; Marchewka, C; Mastovsky, I; Shapiro, M A; Sirigiri, J R; Temkin, R J

2005-01-01

We report operation of a 110 GHz gyrotron with 1.67 MW of output power measured in short pulses (3μs) at an efficiency of 42% in the TE 22,6 mode. We also present a preliminary design of a 1 MW, 120 GHz gyrotron for ITER start-up with an efficiency greater than 50%

Achieving increased bandwidth for 4 degree of freedom self-tuning energy harvester

Science.gov (United States)

Staaf, L. G. H.; Smith, A. D.; Köhler, E.; Lundgren, P.; Folkow, P. D.; Enoksson, P.

2018-04-01

The frequency response of a self-tuning energy harvester composed of two piezoelectric cantilevers connected by a middle beam with a sliding mass is investigated. Measurements show that incorporation of a free-sliding mass increases the bandwidth. Using an analytical model, the system is explained through close investigation of the resonance modes. Resonance mode behavior further suggests that, by breaking the symmetry of the system, even broader bandwidths are achievable.

Miniature Packaging Concept for LNAs in the 200-300 GHz Range

Science.gov (United States)

Samoska, Lorene; Fung, Andy; Varonen, Mikko; Lin, Robert; Peralta, Alejandro; Soria, Mary; Lee, Choonsup; Padmanabhan, Sharmila; Sarkozy, Stephen; Lai, Richard

2016-01-01

In this work, we describe new miniaturized low noise amplifier modules which we developed for incorporation in small-scale satellites or Cubesats, and which exhibit similar or better performance compared to previously reported LNAs in the literature. We have targeted the WR4 (170-260 GHz) and WR3 (220-325 GHz) waveguide bands for the module development. The modules include two different methods of E-plane probes which have been developed for low loss, and stability at high frequencies. MMIC LNAs were also developed for these frequency ranges and fabricated in Northrop Grumman Corporation's 35 nm InP HEMT technology, and we have experimentally verified that noise performance is lower than reported in prior work. The best results include a miniature LNA module with 550K noise at 224 GHz, and a wideband LNA module with 15 dB gain from 230-280 GHz.

Development of 24GHz Rectenna for Receiving and Rectifying Modulated Waves

International Nuclear Information System (INIS)

Shinohara, Naoki; Hatano, Ken

2014-01-01

In this paper, we show experimental results of RF-DC conversion with modulated 24GHz waves. We have already developed class-F MMIC rectenna with resonators for higher harmonics at no modulated 24GHz microwave for RF energy transfer. Dimensions of the MMIC rectifying circuit is 1 mm × 3 mm on GaAs. Maximum RF-DC conversion efficiency is measured 47.9% for a 210 mW microwave input of 24 GHz with a 120 Ω load. The class-F rectenna is based on a single shunt full-wave rectifier. For future application of a simultaneous energy and information transfer system or an energy harvesting from broadcasting waves, input microwave will be modulated. In this paper, we show an experimental result of RF-DC conversion of the class-F rectenna with 24GHz waves modulated by 16QAM as 1st modulation and OFDM as 2nd modulation

Development of 24GHz Rectenna for Receiving and Rectifying Modulated Waves

Science.gov (United States)

Shinohara, Naoki; Hatano, Ken

2014-11-01

In this paper, we show experimental results of RF-DC conversion with modulated 24GHz waves. We have already developed class-F MMIC rectenna with resonators for higher harmonics at no modulated 24GHz microwave for RF energy transfer. Dimensions of the MMIC rectifying circuit is 1 mm × 3 mm on GaAs. Maximum RF-DC conversion efficiency is measured 47.9% for a 210 mW microwave input of 24 GHz with a 120 Ω load. The class-F rectenna is based on a single shunt full-wave rectifier. For future application of a simultaneous energy and information transfer system or an energy harvesting from broadcasting waves, input microwave will be modulated. In this paper, we show an experimental result of RF-DC conversion of the class-F rectenna with 24GHz waves modulated by 16QAM as 1st modulation and OFDM as 2nd modulation.

A program of high power microwave source research and development from 8 GHz to 600 GHz

International Nuclear Information System (INIS)

Granatstein, V.L.; Antonsen, T.M. Jr.; Bidwell, S.; Booske, J.; Carmel, Y.; Destler, W.W.; Kehs, R.A.; Latham, P.E.; Levush, B.; Lou, W.R.; Mayergoyz, I.D.; Minami, K.; Radack, D.J.

1990-01-01

We review research results both on a plasma filled, backward wave oscillator (BWO), and on a free electron laser (FEL) driven by a sheet electron beam. Recently, it was demonstrated that a plasma filled BWO driven by an intense relativistic electron beam can generate hundreds of megawatts of microwave radiation at an unusually high efficiency of 40% compared with a typical efficiency of ∼10% in a BWO without a background plasma. Furthermore, the enhanced efficiency can be maintained even for large electron beam currents approaching the vacuum space charge limiting current, and we anticipate this might hold even for larger current values. Theoretical studies and numerical simulations indicate that the enhanced efficiency as well as a lower value for the start oscillation current in the linear regime may be due to the finite length of the BWO circuit coupled with modification of the dispersion relation due to the background plasma. In the case of our FEL studies, we present designs for a 1 MW, CW, tapered FEL amplifier operating at frequencies of 280 GHz and 560 GHz. A short wiggler period (ell w ∼ 1 cm) is combined with a sheet beam of electrons having energy ∼1 MeV. Depressed collector techniques would allow the main power supply rating to be reduced to ∼200 kV. Efficient sheet beam transport (>99%) has been demonstrated through 10 wiggler periods, and transport through 60 wiggler periods is currently under study. Finally, plans for a proof-of-principle tapered FEL amplifier experiment at 94 GHz are presented. 8 refs., 7 figs

15 Gb/s OFDM-based VLC using direct modulation of 450 GaN laser diode

Science.gov (United States)

Viola, Shaun; Islim, Mohamed Sufyan; Watson, Scott; Videv, Stefan; Haas, Harald; Kelly, Anthony E.

2017-10-01

A record data rate for visible light communications (VLC) using a transistor outline (TO) packaged Gallium Nitride (GaN) laser diode is reported. Using a system 3 dB bandwidth of 1.4 GHz data transmission at 15 Gb/s is reported. This is achieved due to the use of orthogonal frequency division multiplexing (OFDM) in combination with a high system signal to noise ratio (SNR) and adaptive bit loading extending the effective bandwidth to 2.5 GHz. To the best of authors knowledge this is the highest reported data rate for single channel VLC.

A 90 GHz photoinjector

International Nuclear Information System (INIS)

Palmer, D.T.; Hogan, M.J.; Ferrario, M.; Serafini, L.

1999-01-01

Photocathode rf guns depend on mode locked laser systems to produce an electron beam at a given phase of the rf. In general, the laser pulse is less than σ 2 = 10'' of rf phase in length and the required stability is on the order of Δφ = 1 At 90 GHz (W-band), these requirements correspond to σ 2 = 333 fsec and Δφ = 33 fsec. Laser system with pulse lengths in the fsec regime are commercially available, the timing stability is a major concern. It is proposed a multi-cell W-band photoinjector that does not require a mode locked laser system. Thereby eliminating the stability requirements at W-band. The laser pulse is allowed to be many rf periods long. In principle, the photoinjector can now be considered as a thermionic rf gun. Instead of using an alpha magnet to compress the electron bunch, which would have a detrimental effect on the transverse hase space quality due to longitudinal phase space mixing, it is here proposed to use long pulse laser system and a pair of undulators to produce a low emittance, high current, ultra-short electron bunch for beam dynamics experiments in the 90 GHz regime

GHz band frequency hopping PLL-based frequency synthesizers

Institute of Scientific and Technical Information of China (English)

XU Yong; WANG Zhi-gong; GUAN Yu; XU Zhi-jun; QIAO Lu-feng

2005-01-01

In this paper we describe a full-integrated circuit containing all building blocks of a completed PLL-based synthesizer except for low pass filter(LPF).The frequency synthesizer is designed for a frequency hopping (FH) transceiver operating up to 1.5 GHz as a local oscillator. The architecture of Voltage Controlled Oscillator (VCO) is optimized to get better performance, and a phase noise of -111.85-dBc/Hz @ 1 MHz and a tuning range of 250 MHz are gained at a centre frequency of 1.35 GHz.A novel Dual-Modulus Prescaler(DMP) is designed to achieve a very low jitter and a lower power.The settling time of PLL is 80 μs while the reference frequency is 400 KHz.This monolithic frequency synthesizer is to integrate all main building blocks of PLL except for the low pass filter,with a maximum VCO output frequency of 1.5 GHz,and is fabricated with a 0.18 μm mixed signal CMOS process. Low power dissipation, low phase noise, large tuning range and fast settling time are gained in this design.

modeling the effect of bandwidth allocation on network performance

African Journals Online (AJOL)

Using MATLAB, simulations were then .... of the network resource. Network bandwidth design, simulation, and management ... encoder processes longer signal data blocks, which entails longer ... c is the modulated signal carrier. However, the ...

Acousto-optics bandwidth broadening in a Bragg cell based on arbitrary synthesized signal methods.

Science.gov (United States)

Peled, Itay; Kaminsky, Ron; Kotler, Zvi

2015-06-01

In this work, we present the advantages of driving a multichannel acousto-optical deflector (AOD) with a digitally synthesized multifrequency RF signal. We demonstrate a significant bandwidth broadening of ∼40% by providing well-tuned phase control of the array transducers. Moreover, using a multifrequency, complex signal, we manage to suppress the harmonic deflections and return most of the spurious energy to the main beam. This method allows us to operate the AOD with more than an octave of bandwidth with negligible spurious energy going to the harmonic beams and a total bandwidth broadening of over 70%.

Optical Sideband Generation: a Longitudinal Electron Beam Diagnostic Beyond the Laser Bandwidth Resolution Limit

Energy Technology Data Exchange (ETDEWEB)

Lawrence Berkeley National Laboratory; Tilborg, J. van; Matlis, N. H.; Plateau, G. R.; Leemans, W. P.

2010-06-01

Electro-optic sampling (EOS) is widely used as a technique to measure THz-domain electric field pulses such asthe self-fields of femtosecond electron beams. We present an EOS-based approach for single-shot spectral measurement that excels in simplicity (compatible with fiber integration) and bandwidth coverage (overcomes the laser bandwidth limitation), allowing few-fs electron beams or single-cycle THz pulses to be characterized with conventional picosecond probes. It is shown that the EOS-induced optical sidebands on the narrow-bandwidth optical probe are spectrally-shifted replicas of the THz pulse. An experimental demonstration on a 0-3 THz source is presented.

47 CFR 25.250 - Sharing between NGSO MSS Feeder links Earth Stations in the 19.3-19.7 GHz and 29.1-29.5 GHz Bands.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Sharing between NGSO MSS Feeder links Earth Stations in the 19.3-19.7 GHz and 29.1-29.5 GHz Bands. 25.250 Section 25.250 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25...

Ultrahigh bandwidth signal processing

DEFF Research Database (Denmark)

Oxenløwe, Leif Katsuo

2016-01-01

Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, an hence useful for all types of data signals including coherent multi......-level modulation founats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signa In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral...... regeneratio These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platform like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described....

Comparison of Available Bandwidth Estimation Techniques in Packet-Switched Mobile Networks

DEFF Research Database (Denmark)

López Villa, Dimas; Ubeda Castellanos, Carlos; Teyeb, Oumer Mohammed

2006-01-01

The relative contribution of the transport network towards the per-user capacity in mobile telecommunication systems is becoming very important due to the ever increasing air-interface data rates. Thus, resource management procedures such as admission, load and handover control can make use...... of information regarding the available bandwidth in the transport network, as it could end up being the bottleneck rather than the air interface. This paper provides a comparative study of three well known available bandwidth estimation techniques, i.e. TOPP, SLoPS and pathChirp, taking into account...

95 GHz methanol masers near DR 21 and DR 21(OH)

International Nuclear Information System (INIS)

Plambeck, R.L.; Menten, K.M.

1990-01-01

The BIMA array is used to map the 95-GHz 8(0) to 7 1A(+) transition of methanol and the 98-GHz J = 2-1 transition of CS toward the DR 21(OH) and DR 21 star-forming regions. Several strong methanol masers were found. The positions of the two brightest masers were measured with an accuracy of about + or - 0.3 arcsec. Toward DR 21(OH), the positions, velocities, and line shapes of the 95 GHz masers are in excellent agreement with those of the 84-GHz 5(-1) to 4 () methanol masers previously mapped by Batrla and Menten (1988), demonstrating that maser emission in both transitions originates from the same clumps of gas. The methanol masers are offset from CS emission peaks and from other known infrared and maser sources; they may possibly be clustered along the interface between outflows, traced by shock-excited H2 emission, and dense ambient gas, traced by CS emission. 25 refs

Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics

Energy Technology Data Exchange (ETDEWEB)

Chen, Sen; Luo, Sheng-Nian

2018-02-16

Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10–100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are exploredviaGaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics.

Science.gov (United States)

Chen, Sen; Luo, Sheng Nian

2018-03-01

Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10-100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are explored via Gaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

A wide-bandwidth and high-sensitivity robust microgyroscope

International Nuclear Information System (INIS)

Sahin, Korhan; Sahin, Emre; Akin, Tayfun; Alper, Said Emre

2009-01-01

This paper reports a microgyroscope design concept with the help of a 2 degrees of freedom (DoF) sense mode to achieve a wide bandwidth without sacrificing mechanical and electronic sensitivity and to obtain robust operation against variations under ambient conditions. The design concept is demonstrated with a tuning fork microgyroscope fabricated with an in-house silicon-on-glass micromachining process. When the fabricated gyroscope is operated with a relatively wide bandwidth of 1 kHz, measurements show a relatively high raw mechanical sensitivity of 131 µV (° s −1 ) −1 . The variation in the amplified mechanical sensitivity (scale factor) of the gyroscope is measured to be less than 0.38% for large ambient pressure variations such as from 40 to 500 mTorr. The bias instability and angle random walk of the gyroscope are measured to be 131° h −1 and 1.15° h −1/2 , respectively

High-performance CPW MMIC LNA using GaAs-based metamorphic HEMTs for 94-GHz applications

International Nuclear Information System (INIS)

Ryu, Keun-Kwan; Kim, Sung-Chan; An, Dan; Rhee, Jin-Koo

2010-01-01

In this paper, we report on a high-performance low-noise amplifier (LNA) using metamorphic high-electron-mobility transistor (MHEMT) technology for 94-GHz applications. The 100 nm x 60 μm MHEMT devices for the coplanar MMIC LNA exhibited DC characteristics with a drain current density of 655 mA/mm and an extrinsic transconductance of 720 mS/mm. The current gain cutoff frequency (f T ) and the maximum oscillation frequency (f max ) were 195 GHz and 305 GHz, respectively. Based on this MHEMT technology, coplanar 94-GHz MMIC LNAs were realized, achieving a small signal gain of more than 13 dB between 90 and 100 GHz and a small signal gain of 14.8 dB and a noise figure of 4.7 dB at 94 GHz.

A 250-GHz CARM [Cyclotron Auto Resonance Maser] oscillator experiment driven by an induction linac

International Nuclear Information System (INIS)

Caplan, M.; Kulke, B.; Bubp, D.G.; McDermott, D.; Luhmann, N.

1990-01-01

A 250-GHz Cyclotron Auto Resonance Maser (CARM) oscillator has been designed and constructed and will be tested using a 1-kA, 2-MeV electron beam produced by the induction linac at the Accelerator Research Center (ARC) facility of Lawrence Livermore National Laboratory (LLNL). The oscillator circuit was made to operate in the TE 11 mode at ten times cutoff using waveguide Bragg reflectors to create an external cavity Q of 8000. Theory predicts cavity fill times of less than 30 ns (pulse length) and efficiencies approaching 20% is sufficiently low transverse electron velocity spreads are maintained (2%)

Lightning and 85-GHz MCSs in the Global Tropics

Science.gov (United States)

Toracinta, E. Richard; Zipser, E. J.

1999-01-01

Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C Lightning Imaging Sensor (LIS), and the first space-borne radar, facilitates high-resolution case studies of MCS structure throughout the global tropics. An important precursor, however, is to better understand the distribution of MCSs and lightning in the tropics. With that objective in mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

47 CFR 25.136 - Licensing provisions for user transceivers in the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile...

Science.gov (United States)

2010-10-01

...) Incorporation of ancillary terrestrial component base station into an L-band mobile-satellite service system... ancillary terrestrial component (ATC) base stations as defined in § 25.201 at its own risk and subject to... Applications and Licenses Earth Stations § 25.136 Licensing provisions for user transceivers in the 1.6/2.4 GHz...

Analysis of 38 GHz mmWave Propagation Characteristics of Urban Scenarios

DEFF Research Database (Denmark)

Rodriguez Larrad, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard

2015-01-01

The 38 GHz mm-wave frequency band is a strong candidate for the future deployment of wireless systems. Compared to lower frequency bands, propagation in the 38 GHz band is relatively unexplored for access networks in urban scenarios. This paper presents a detailed measurement-based analysis of ur...

Diseño y validación de un radar CW-FM a 94 GHz

OpenAIRE

Varela Agrelo, David

2013-01-01

Diseño y validación de un radar CW-FM a 9g GHz 94 GHz CW-FM radar design and mesurement campaign validation. Desarrollo de un radar CW-FM a 94GHz y verificación de los resultados obtenidos durante la etapa de medidas. Desevolupament d'un radar CW-FM a 94GHz i verificació dels resultat obteinguts durante l'etapa de mesures.

Experimental Demonstration of 84 Gb/s PAM-4 Over up to 1.6 km SSMF Using a 20-GHz VCSEL at 1525 nm

DEFF Research Database (Denmark)

Eiselt, Nicklas; Griesser, Helmut; Wei, Jinlong

2017-01-01

We demonstrate 84-Gb/s four-level pulse amplitude modulation (PAM-4) over up to 1.6-km standard single mode fiber using a 20-GHz single mode short cavity vertical cavity surface emitting laser diode at a transmission wavelength of 1525 nm. Different equalizer approaches including a common...... feedforward equalizer, a nonlinear Volterra equalizer (NLVE), a maximum likelihood sequence estimator (MLSE) and their combinations are evaluated working either as an equalizer for a standard PAM-4 or a partial response PAM-4 signal with seven levels. It is demonstrated that a standard FFE is not enough...... for a transmission distance of >0.6 km, while the use of an NLVE or FFE + MLSE is able to improve the transmission distance towards 1 km. The use of partial-response PAM-4 FFE in combination with a short memory MLSE is able to efficiently equalize the bandwidth limitations, showing more than 10-times BER improvement...

Fabrication of hierarchical graphene@Fe3O4@SiO2@polyaniline quaternary composite and its improved electrochemical performance

International Nuclear Information System (INIS)

Wang, Lei; Zhu, Jianfeng; Yang, Haibo; Wang, Fen; Qin, Yi; Zhao, Ting; Zhang, Pei

2015-01-01

Highlights: • Graphene@Fe 3 O 4 @SiO 2 @polyaniline hierarchical structures have been fabricated. • The reflection loss of the composites is below −10 dB in 10.5–16.3 GHz. • The maximum absorption of the composites is −40.7 dB at 12.5 GHz. - Abstract: Hierarchical graphene@Fe 3 O 4 @SiO 2 @polyaniline quaternary composite is fabricated subtly. Their microwave absorption properties are also investigated in the 2–18 GHz frequency range. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) reveal that Fe 3 O 4 @SiO 2 @polyaniline core@shell@shell heteronanostructures are densely covered on the surfaces of graphene, and form hierarchical structures. Compared with two-dimensional binary nanocomposites of graphene@Fe 3 O 4 , the hierarchical structure exhibits enhanced EM absorption in terms of both the maximum reflection loss value and the absorption bandwidth. The maximum reflection loss value can reach −40.7 dB at 12.5 GHz with a thickness of 2.5 mm and the bandwidth corresponding to the reflection loss below −10 dB is 5.8 GHz (from 10.5 to 16.3 GHz)

A Study on the Bandwidth Characteristics of Pleated Pneumatic Artificial Muscles

Directory of Open Access Journals (Sweden)

Rino Versluys

2009-01-01

Full Text Available Pleated pneumatic artificial muscles have interesting properties that can be of considerable significance in robotics and automation. With a view to the potential use of pleated pneumatic artificial muscles as actuators for a fatigue test bench (high forces and small displacements, the bandwidth characteristics of a muscle-valve system were investigated. Bandwidth is commonly used for linear systems, as the Bode plot is independent of the amplitude of the input signal. However, due to the non-linear behaviour of pleated pneumatic artificial muscles, the system's gain becomes dependent on the amplitude of the input sine wave. As a result, only one Bode plot is insufficient to clearly describe or identify a non-linear system. In this study, the bandwidth of a muscle-valve system was assessed from two perspectives: a varying amplitude and a varying offset of the input sine wave. A brief introduction to pneumatic artificial muscles is given. The concept of pleated pneumatic artificial muscles is explained. Furthermore, the different test methods and experimental results are presented.

On-chip micromachined dipole antenna with parasitic radiator for mm-wave wireless systems

KAUST Repository

Sallam, Mai O.; Serry, Mohamed; Shamim, Atif; Sedky, Sherif; Soliman, Ezzeldin A.

2016-01-01

In this paper, we present a micromachined dipole antenna with parasitic radiator. The antenna is designed for operation at 60 GHz. It consists of two Ig/2 dipole radiators fed by coplanar strips waveguide. Two slightly shorter dipoles are placed in proximity to the main radiators. They act as parasitic dipole arms which increase the bandwidth of the antenna. Two versions of the same antenna topology are presented in this paper in which one uses a high resistivity silicon substrate while the other uses a low resistivity one. The proposed antenna was optimized using HFSS and the final design was simulated using both HFSS and CST for verifying the obtained results. Both simulators are in good agreement. They show that the antenna has very good radiation characteristics where its directivity is around 7.5 dBi. The addition of the parasitic arms increased the bandwidth of the antenna from 1.3 GHz (3.62 GHz) to 4.3 GHz (7.44 GHz) when designed on high (low) resistivity silicon substrate.

Dynamic Characteristics of S-band DC SQUID Amplifier

DEFF Research Database (Denmark)

Prokopenko, G. V.; Shitov, S. V.; Koshelets, I. L. L. V. P.

2003-01-01

A low-noise rf amplifier based on a de SQUID (SQA) has been tested in the frequency range 3.0-4.6 GHz in the open-loop configuration. The following parameters have been measured for the single-stage balanced type SQA at 4.0 GHz: gain (12 +/- 1) dB, 3 dB bandwidth of 500 MHz and noise temperature (1.......0 +/- 0.25) K. For the nonbalanced type SQA at 4.0 GHz gain was (15 +/-1) dB, 3 dB bandwidth 200 MHz and noise temperature (0.5 +/- 0.25) K. The improved performance is obtained due to the increased characteristic voltage (approximate to 420 muV) of the small-area (down to 0.7-0.9 mum(2)) high-quality Nb......-AlOx-Nb SIS junctions. The saturation power (normalized to 1 GHz) referred to the input at 1 dB gain compression is estimated as approximate to55 K*GHz at a bias voltage of 60 muV. The reasons for saturation of the SQA are discussed....

On-chip micromachined dipole antenna with parasitic radiator for mm-wave wireless systems

KAUST Repository

Sallam, Mai O.

2016-12-19

In this paper, we present a micromachined dipole antenna with parasitic radiator. The antenna is designed for operation at 60 GHz. It consists of two Ig/2 dipole radiators fed by coplanar strips waveguide. Two slightly shorter dipoles are placed in proximity to the main radiators. They act as parasitic dipole arms which increase the bandwidth of the antenna. Two versions of the same antenna topology are presented in this paper in which one uses a high resistivity silicon substrate while the other uses a low resistivity one. The proposed antenna was optimized using HFSS and the final design was simulated using both HFSS and CST for verifying the obtained results. Both simulators are in good agreement. They show that the antenna has very good radiation characteristics where its directivity is around 7.5 dBi. The addition of the parasitic arms increased the bandwidth of the antenna from 1.3 GHz (3.62 GHz) to 4.3 GHz (7.44 GHz) when designed on high (low) resistivity silicon substrate.

RADIO SOURCES FROM A 31 GHz SKY SURVEY WITH THE SUNYAEV-ZEL'DOVICH ARRAY

International Nuclear Information System (INIS)

Muchovej, Stephen; Hawkins, David; Lamb, James; Woody, David; Leitch, Erik; Carlstrom, John E.; Culverhouse, Thomas; Greer, Chris; Hennessy, Ryan; Loh, Michael; Marrone, Daniel P.; Pryke, Clem; Sharp, Matthew; Joy, Marshall; Miller, Amber; Mroczkowski, Tony

2010-01-01

We present the first sample of 31 GHz selected sources to flux levels of 1 mJy. From late 2005 to mid-2007, the Sunyaev-Zel'dovich Array observed 7.7 deg 2 of the sky at 31 GHz to a median rms of 0.18 mJy beam -1 . We identify 209 sources at greater than 5σ significance in the 31 GHz maps, ranging in flux from 0.7 mJy to ∼200 mJy. Archival NVSS data at 1.4 GHz and observations at 5 GHz with the Very Large Array are used to characterize the sources. We determine the maximum-likelihood integrated source count to be N(>S) = (27.2 ± 2.5)deg -2 x (S mJy ) -1.18±0.12 over the flux range 0.7-15 mJy. This result is significantly higher than predictions based on 1.4 GHz selected samples, a discrepancy which can be explained by a small shift in the spectral index distribution for faint 1.4 GHz sources. From comparison with previous measurements of sources within the central arcminute of massive clusters, we derive an overdensity of 6.8 ± 4.4, relative to field sources.

Controlling Laser Plasma Instabilities Using Temporal Bandwidths Under Shock Ignition Relevant Conditions

Science.gov (United States)

Tsung, Frank; Weaver, J.; Lehmberg, R.

2017-10-01

We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temporal bandwidth under plasma conditions relevant to experiments on the Nike laser with induced spatial incoherence (ISI). With ISI, the instantaneous laser intensity can be 3-4 times larger than the average intensity, leading to the excitation of additional TPD modes and producing electrons with larger angular spread. In our simulations, we observe that although ISI can increase the interaction regions for short bursts of time, time-averaged (over many pico-seconds) laser plasma interactions can be reduced by a factor of 2 in systems with sufficiently large bandwidths (where the inverse bandwidth is comparable with the linear growth time). We will quantify these effects and investigate higher dimensional effects such as laser speckles and the effects of Coulomb collisions. Work supported by NRL, NNSA, and NSF.

Photonic-band-gap gyrotron amplifier with picosecond pulses

Science.gov (United States)

Nanni, Emilio A.; Jawla, Sudheer; Lewis, Samantha M.; Shapiro, Michael A.; Temkin, Richard J.

2017-12-01

We report the amplification of 250 GHz pulses as short as 260 ps without observation of pulse broadening using a photonic-band-gap circuit gyrotron traveling-wave-amplifier. The gyrotron amplifier operates with a device gain of 38 dB and an instantaneous bandwidth of 8 GHz. The operational bandwidth of the amplifier can be tuned over 16 GHz by adjusting the operating voltage of the electron beam and the magnetic field. The amplifier uses a 30 cm long photonic-band-gap interaction circuit to confine the desired TE03-like operating mode while suppressing lower order modes which can result in undesired oscillations. The circuit gain is >55 dB for a beam voltage of 23 kV and a current of 700 mA. These results demonstrate the wide bandwidths and a high gain achievable with gyrotron amplifiers. The amplification of picosecond pulses of variable lengths, 260-800 ps, shows good agreement with the theory using the coupled dispersion relation and the gain-spectrum of the amplifier as measured with quasi-CW input pulses.

MM wave quasioptical SIS mixers

International Nuclear Information System (INIS)

Hu, Qing; Mears, C.A.; Richards, P.L.; Lloyd, F.L.

1988-08-01

We have tested the performance of planar SIS mixers with log-periodic antennas at near millimeter and submillimeter wave frequencies from 90 to 360 GHz. The large ωR/sub N/C product (/approximately/10 at 90 GHz) of our Nb/NbO/sub x//Pb-In-Au junctions requires an integrated inductive tuning element to resonate the junction capacitance at the operating frequencies. We have used two types of integrated tuning element, which were designed with the aid of measurements using a Fourier transform spectrometer. Preliminary results indicate that the tuning elements can give very good mixer performance up to at least 200 GHz. An inductive wire in parallel with a 5-junction array gives a minimum mixer noise temperature of 115K (DSB) at 90 GHz with a FWHM bandwidth of 8 GHz. An open-ended microstrip stub in parallel with a single junction, gives minimum mixer noise temperatures of 150 and 200K (DSB) near 90 and 180 GHz with FWHM bandwidths of 4 and 3 GHz, respectively. The relatively high mixer noise temperatures compared to those of waveguide SIS mixers in a similar frequency range are attributed mainly to the losses in our optical system, which is being improved. 13 refs., 6 figs., 1 tab

A DOUBLE E SHAPED MICROSTRIP PATCH ANTENNA FOR MULTIBAND APPLICATIONS

Directory of Open Access Journals (Sweden)

Pristin K Mathew

2014-06-01

Full Text Available This paper presents a dual band Compact double E shaped Microstrip Patch antenna with enhanced gain for Worldwide Interoperability for Microwave Access (WI-MAX, Universal Mobile Telecommunication Systems (UMTS and Satellite applications. The modified E shaped patch antenna is designed using CADFEKO and the results of return loss, Voltage Standing Wave Ratio (VSWR, gain of the proposed antenna are compared with a conventional E shaped patch antenna. The results show that the double E shaped wideband patch antenna has an impedance bandwidth of 10.7 % with a return loss of -13.6dB, -12.4 dB, -12.1dB and -14.2dB at resonant frequencies of 1.96 GHz, 3.62 GHz, 5.76 GHz and 6.82 GHz, whereas a conventional E shaped patch antenna operates at 2.5 GHz, 3.4 GHz and 5.5 GHz with a return loss of -16 dB each and impedance bandwidth of 10.6 %. Both the antennas uses Coaxial Probe feeding technique and Flame Retardant 4 (FR-4 as the substrate material with a thickness of 2.87 mm. A parametric study has been done so as to understand the effect of each parameter to obtain a better performance and optimised results.

Optical switching in data centers : architectures based on optical packet/burst switching

NARCIS (Netherlands)

Calabretta, Nicola; Miao, Wang; Testa, F.; Pavesi, L.

2017-01-01

Driven by the cloud computing, Internet of things, and emerging big data applications, more stringent requirements in terms of high bandwidth, low latency, and large interconnectivity are imposed on the communications within the data centers (DC). Traditional intra-DC network based on electronic

Building the Teraflops/Petabytes Production Computing Center

International Nuclear Information System (INIS)

Kramer, William T.C.; Lucas, Don; Simon, Horst D.

1999-01-01

In just one decade, the 1990s, supercomputer centers have undergone two fundamental transitions which require rethinking their operation and their role in high performance computing. The first transition in the early to mid-1990s resulted from a technology change in high performance computing architecture. Highly parallel distributed memory machines built from commodity parts increased the operational complexity of the supercomputer center, and required the introduction of intellectual services as equally important components of the center. The second transition is happening in the late 1990s as centers are introducing loosely coupled clusters of SMPs as their premier high performance computing platforms, while dealing with an ever-increasing volume of data. In addition, increasing network bandwidth enables new modes of use of a supercomputer center, in particular, computational grid applications. In this paper we describe what steps NERSC is taking to address these issues and stay at the leading edge of supercomputing centers.; N

Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Petroleum Refining

Energy Technology Data Exchange (ETDEWEB)

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. petroleum refining. The study relies on multiple sources to estimate the energy used in nine individual process areas, representing 68% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

Microelectromechanical filter formed from parallel-connected lattice networks of contour-mode resonators

Science.gov (United States)

Wojciechowski, Kenneth E; Olsson, III, Roy H; Ziaei-Moayyed, Maryam

2013-07-30

A microelectromechanical (MEM) filter is disclosed which has a plurality of lattice networks formed on a substrate and electrically connected together in parallel. Each lattice network has a series resonant frequency and a shunt resonant frequency provided by one or more contour-mode resonators in the lattice network. Different types of contour-mode resonators including single input, single output resonators, differential resonators, balun resonators, and ring resonators can be used in MEM filter. The MEM filter can have a center frequency in the range of 10 MHz-10 GHz, with a filter bandwidth of up to about 1% when all of the lattice networks have the same series resonant frequency and the same shunt resonant frequency. The filter bandwidth can be increased up to about 5% by using unique series and shunt resonant frequencies for the lattice networks.

Bandwidth provisioning in infrastructure-based wireless networks employing directional antennas

Energy Technology Data Exchange (ETDEWEB)

Hasiviswanthan, Shiva [Los Alamos National Laboratory; Zhao, Bo [PENN STATE UNIV.; Vasudevan, Sudarshan [UNIV OF MASS AMHERST; Yrgaonkar, Bhuvan [PENN STATE UNIV.

2009-01-01

Motivated by the widespread proliferation of wireless networks employing directional antennas, we study the problem of provisioning bandwidth in such networks. Given a set of subscribers and one or more access points possessing directional antennas, we formalize the problem of orienting these antennas in two fundamental settings: (1) subscriber-centric, where the objective is to fairly allocate bandwidth among the subscribers and (2) provider-centric, where the objective is to maximize the revenue generated by satisfying the bandwidth requirements of subscribers. For both the problems, we first design algorithms for a network with only one access point working under the assumption that the number of antennas does not exceed the number of noninterfering channels. Using the well-regarded lexicographic max-min fair allocation as the objective for a subscriber-centric network, we present an optimum dynamic programming algorithm. For a provider-centric network, the allocation problem turns out to be NP-hard. We present a greedy heuristic based algorithm that guarantees almost half of the optimum revenue. We later enhance both these algorithms to operate in more general networks with multiple access points and no restrictions on the relative numbers of antennas and channels. A simulation-based evaluation using OPNET demonstrates the efficacy of our approaches and provides us further in insights into these problems.

Measuring the service level in the 2.4 GHz ISM band

NARCIS (Netherlands)

van Bloem, J.W.H.; Schiphorst, Roelof

2011-01-01

In this report we provide the findings of the 2.4 GHz service level research. Here service level means the following: can all devices in the 2.4 GHz band fulfill their communication needs. In other words this corresponds to the overall Quality of Service (QoS). The project is a short research

Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

KAUST Repository

Nafe, Ahmed

2015-04-13

In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing of nano-particle based conductive ink on the broad faces as well as on sides of the substrate. The operating frequency of the antenna can be tuned by applying a variable static bias magnetic field that controls the permeability of the host ferrite substrate. The antenna operates about a center frequency of approximately 14 GHz with an instantaneous impedance bandwidth of 75 MHz. A fabricated prototype has demonstrated a tuning range of 10% (1.5 GHz) using an applied bias magnetic field of 3 kOe yielding it especially attractive for tunable and reconfigurable yet low cost microwave systems.

Ultra-broadband Nonlinear Microwave Monolithic Integrated Circuits in SiGe, GaAs and InP

DEFF Research Database (Denmark)

Krozer, Viktor; Johansen, Tom Keinicke; Djurhuus, Torsten

2006-01-01

.5 GHz and ≫ 10 GHz for SiGe BiCMOS and GaAs MMIC, respectively. Analysis of the frequency behaviour of frequency converting devices is presented for improved mixer design. Millimeter-wave front-end components for advanced microwave imaging and communications purposes have also been demonstrated......Analog MMIC circuits with ultra-wideband operation are discussed in view of their frequency limitation and different circuit topologies. Results for designed and fabricated frequency converters in SiGe, GaAs, and InP technologies are presented in the paper. RF type circuit topologies exhibit a flat...... conversion gain with a 3 dB bandwidth of 10 GHz for SiGe and in excess of 20 GHz for GaAs processes. The concurrent LO-IF isolation is better than -25 dB, without including the improvement due to the combiner circuit. The converter circuits exhibit similar instantaneous bandwidth at IF and RF ports of ≫ 7...

Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for WLAN/WiMAX Applications

Science.gov (United States)

Li, Jianxing; Guo, Jianying; He, Bin; Zhang, Anxue; Liu, Qing Huo

2016-11-01

A novel uniplanar CPW-fed tri-band stub-loaded slot antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. Dual resonant modes were effectively excited in the upper band by using two identical pairs of slot stubs and parasitic slots symmetrically along the arms of a traditional CPW-fed slot dipole, achieving a much wider bandwidth. The middle band was realized by the fundamental mode of the slot dipole. To obtain the lower band, two identical inverted-L-shaped open-ended slots were symmetrically etched in the ground plane. A prototype was fabricated and measured, showing that tri-band operation with 10-dB return loss bandwidths of 150 MHz from 2.375 to 2.525 GHz, 725 MHz from 3.075 to 3.8 GHz, and 1.9 GHz from 5.0 to 6.9 GHz has been achieved. Details of the antenna design as well as the measured and simulated results are presented and discussed.

10 GHz ECRIS for Warsaw Cyclotron

CERN Document Server

Sudlitz, K

1999-01-01

Cusp type, 10 GHz ECRIS has been built and tested earlier. For obtaining intensive beams, more relevant for cyclotron, cusp geometry has been replaced by hexapole. Discharge chamber (stainless steel, 50 mm diameter, 250 mm long) is an extension of a coaxial line, feeding RF (9,6 GHz, up to 200 W) to the plasma. The NdFeB hexapole (0,52 T on the surface) has been used. The axial magnetic field is created by water cooled coils. The axial injection line dedicated to K160 isochronous heavy ion cyclotron has been constructed. The line consists of Glaser lenses, double focusing magnet, solenoid and mirror type inflector. The system provides sufficient transmission of the beam from ECR ion source to the firsts orbits of the cyclotron for m/q ranging from 7 to 2. After successful initial tests which were done in July 1997 the ECRIS serves as an external source for Warsaw Cyclotron.

Optimization of Joint Power and Bandwidth Allocation in Multi-Spot-Beam Satellite Communication Systems

Directory of Open Access Journals (Sweden)

Heng Wang

2014-01-01

Full Text Available Multi-spot-beam technique has been widely applied in modern satellite communication systems. However, the satellite power and bandwidth resources in a multi-spot-beam satellite communication system are scarce and expensive; it is urgent to utilize the resources efficiently. To this end, dynamically allocating the power and bandwidth is an available way. This paper initially formulates the problem of resource joint allocation as a convex optimization problem, taking into account a compromise between the maximum total system capacity and the fairness among the spot beams. A joint bandwidth and power allocation iterative algorithm based on duality theory is then proposed to obtain the optimal solution of this optimization problem. Compared with the existing separate bandwidth or power optimal allocation algorithms, it is shown that the joint allocation algorithm improves both the total system capacity and the fairness among spot beams. Moreover, it is easy to be implemented in practice, as the computational complexity of the proposed algorithm is linear with the number of spot beams.

Design and Development of Compact Microstrip Patch Antenna for Wireless Applications

Directory of Open Access Journals (Sweden)

R. Nagendra

2017-09-01

Full Text Available In this paper, a novel dual band microstrip patch antenna based on composite patch antenna and radiating part. By selecting a suitable offset feed position, it is feasible to provide 50Ω characteristic impedance and thus making better impedance matching. The proposed antenna has been improved broader bandwidth by using RT Duroid substrate. The radiating part is plays a important role in creating a lower operating band (2.45 GHz in addition to achieve miniaturization. The proposed antenna has to be fabricated with RT / Duroid substrate and dimensions of 19 × 22 × 0.8 mm. The measured -10 dB bandwidth of 200 MHz at 2.45 GHz and 990 MHz at 5.45 GHz, which is quite useful for Industrial, Scientific and Medical (ISM and WLAN applications.

Enhanced traveling wave amplification of co-planar slow wave structure by extended phase-matching

International Nuclear Information System (INIS)

Palm, Andrew; Sirigiri, Jagadishwar; Shin, Young-Min

2015-01-01

The electron beam co-propagating with slow waves in a staggered double grating array (SDGA) efficiently amplifies millimeter and sub-millimeter waves over a wide spectrum. Our theoretical and numerical analyses show that the power amplification in the fundamental passband is enhanced by the extended beam-wave phase-matching. Particle-in-cell simulations on the SDGA slow wave structure, designed with 10.4 keV and 50–100 mA sheet beam, indicate that maintaining beam-wave synchronization along the entire length of the circuit improves the gain by 7.3% leading to a total gain of 28 dB, corresponding to 62 W saturated power at the middle of operating band, and a 3-dB bandwidth of 7 GHz with 10.5% at V-band (73.5 GHz center frequency) with saturated peak power reaching 80 W and 28 dB at 71 GHz. These results also show a reasonably good agreement with analytic calculations based on Pierce small signal gain theory

Probabilistic Bandwidth Assignment in Wireless Sensor Networks

OpenAIRE

Khan , Dawood; Nefzi , Bilel; Santinelli , Luca; Song , Ye-Qiong

2012-01-01

International audience; With this paper we offer an insight in designing and analyzing wireless sensor networks in a versatile manner. Our framework applies probabilistic and component-based design principles for the wireless sensor network modeling and consequently analysis; while maintaining flexibility and accuracy. In particular, we address the problem of allocating and reconfiguring the available bandwidth. The framework has been successfully implemented in IEEE 802.15.4 using an Admissi...

A 60 GHz Dual-Polarized Probe for Spherical Near-Field Measurements

DEFF Research Database (Denmark)

Popa, Paula Irina; Breinbjerg, Olav

2017-01-01

to waveguide adapters up to 67 GHz for OMT-switch connection. A 27 dBi gain conical horn is designed by using WIPL-D software and in-house manufactured. The 60 GHz probe system is being assembled and tested in planar near-field (PNF) setup at DTU. The results are validated by comparison with WIPL-D simulations...

Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics.

Science.gov (United States)

Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Yasuda, Y; Morinobu, S; Tamii, A; Kamakura, K

2014-02-01

An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

Multi-directional plasmonic surface-wave splitters with full bandwidth isolation

International Nuclear Information System (INIS)

Gao, Zhen; Gao, Fei; Zhang, Baile

2016-01-01

We present a multidirectional plasmonic surface-wave splitter with full bandwidth isolation experimentally based on coupled defect surface modes in a surface-wave photonic crystal. In contrast to conventional plasmonic surface-wave frequency splitters with polaritonic dispersion relations that overlap at low frequencies, this multidirectional plasmonic surface-wave splitter based on coupled defect surface modes can split different frequency bands into different waveguide branches without bandwidth overlap. Transmission spectra and near-field imaging measurements have been implemented in the microwave frequencies to verify the performance of the multidirectional plasmonic surface-wave splitter. This surface wave structure can be used as a plasmonic wavelength-division multiplexer that may find potential applications in the surface-wave integrated circuits from microwave to terahertz frequencies.