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Sample records for metamaterial-based subwavelength antenna

  1. Topology Optimization of Sub-Wavelength Antennas

    DEFF Research Database (Denmark)

    Erentok, Aycan; Sigmund, Ole

    2011-01-01

    We propose a topology optimization strategy for the systematic design of a three-dimensional (3D), conductor-based sub-wavelength antenna. The post-processed finite-element (FE) models of the optimized structure are shown to be self-resonant, efficient and exhibit distorted omnidirectional...

  2. Deep-subwavelength Decoupling for MIMO Antennas in Mobile Handsets with Singular Medium.

    Science.gov (United States)

    Xu, Su; Zhang, Ming; Wen, Huailin; Wang, Jun

    2017-09-22

    Decreasing the mutual coupling between Multi-input Multi-output (MIMO) antenna elements in a mobile handset and achieving a high data rate is a challenging topic as the 5 th -generation (5G) communication age is coming. Conventional decoupling components for MIMO antennas have to be re-designed when the geometries or frequencies of antennas have any adjustment. In this paper, we report a novel metamaterial-based decoupling strategy for MIMO antennas in mobile handsets with wide applicability. The decoupling component is made of subwavelength metal/air layers, which can be treated as singular medium over a broad frequency band. The flexible applicable property of the decoupling strategy is verified with different antennas over different frequency bands with the same metamaterial decoupling element. Finally, 1/100-wavelength 10-dB isolation is demonstrated for a 24-element MIMO antenna in mobile handsets over the frequency band from 4.55 to 4.75 GHz.

  3. Antenna-assisted enhanced transmission through subwavelength nanoholes

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Peng, Liang; Mortensen, Asger

    2010-01-01

    By structural engineering of sub-wavelength apertures, we numerically demonstrate that transmission through apertures can be significantly enhanced. Based on equivalent circuit theory analysis, structured apertures are obtained with a 1900-fold transmission enhancement factor. We show that the en......By structural engineering of sub-wavelength apertures, we numerically demonstrate that transmission through apertures can be significantly enhanced. Based on equivalent circuit theory analysis, structured apertures are obtained with a 1900-fold transmission enhancement factor. We show...

  4. Properties of Sub-wavelength Resonances in Metamaterial Cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Clausen, N.C.J.; Pedersen, R.R.

    2008-01-01

    The analytical solution for the canonical configuration with electric line source illumination of concentric metamaterial cylinders is employed to study the properties of the observed sub-wavelength resonances. The near- and far-field distributions, the frequency and geometry bandwidths, and the ......, and the line source impedance are investigated for varying electromagnetic and geometrical parameters. The results of this study are of importance for metamaterial-based miniaturization of antennas....

  5. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    Md. Moinul Islam

    2015-01-01

    Full Text Available A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR and capacitance-loaded strip (CLS unit cells is presented for Ultra wideband (UWB microwave imaging applications. Four left-handed (LH metamaterial (MTM unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR with a capacitance-loaded strip (CLS to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

  6. Research on radiation characteristics of dipole antenna modulation by sub-wavelength inhomogeneous plasma layer

    Directory of Open Access Journals (Sweden)

    Fanrong Kong

    2018-02-01

    Full Text Available The modulation and enhancement effect of sub-wavelength plasma structures on compact antennas exhibits obvious technological advantage and considerable progress. In order to extend the availability of this technology under complex and actual environment with inhomogeneous plasma structure, a numerical simulation analysis based on finite element method has been conducted in this paper. The modulation function of the antenna radiation with sub-wavelength plasma layer located at different positions was investigated, and the inhomogeneous plasma layer with multiple electron density distribution profiles were employed to explore the effect of plasma density distribution on the antenna radiation. It has been revealed that the optical near-field modulated distance and reduced plasma distribution are more beneficial to enhance the radiation. On the basis above, an application-focused research about communication through the plasma sheath surrounding a hypersonic vehicle has been carried out aiming at exploring an effective communication window. The relevant results devote guiding significance in the field of antenna radiation modulation and enhancement, as well as the development of communication technology in hypersonic flight.

  7. Research on radiation characteristics of dipole antenna modulation by sub-wavelength inhomogeneous plasma layer

    Science.gov (United States)

    Kong, Fanrong; Chen, Peiqi; Nie, Qiuyue; Zhang, Xiaoning; Zhang, Zhen; Jiang, Binhao

    2018-02-01

    The modulation and enhancement effect of sub-wavelength plasma structures on compact antennas exhibits obvious technological advantage and considerable progress. In order to extend the availability of this technology under complex and actual environment with inhomogeneous plasma structure, a numerical simulation analysis based on finite element method has been conducted in this paper. The modulation function of the antenna radiation with sub-wavelength plasma layer located at different positions was investigated, and the inhomogeneous plasma layer with multiple electron density distribution profiles were employed to explore the effect of plasma density distribution on the antenna radiation. It has been revealed that the optical near-field modulated distance and reduced plasma distribution are more beneficial to enhance the radiation. On the basis above, an application-focused research about communication through the plasma sheath surrounding a hypersonic vehicle has been carried out aiming at exploring an effective communication window. The relevant results devote guiding significance in the field of antenna radiation modulation and enhancement, as well as the development of communication technology in hypersonic flight.

  8. Terahertz wave manipulation with metamaterials based on metal and graphene

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Zalkovskij, Maksim

    2013-01-01

    response. In this presentation we overview our results on theory, fabrication and characterization of metal and graphene based metamaterials for the THz range. We show that the multiple layers of structured graphene can form a hyperbolic dispersion medium lens able to resolve the subwavelength features [2......]. We analyze the limitations and demonstrate numerically and experimentally the chiral and nonchiral thin-film metamaterial based polarization converters [3–5] and graphene total absorbers for THz radiation [6]....

  9. Aperiodic-metamaterial-based absorber

    Directory of Open Access Journals (Sweden)

    Quanlong Yang

    2017-09-01

    Full Text Available The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber, how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  10. Towards strong light-matter coupling at the single-resonator level with sub-wavelength mid-infrared nano-antennas

    Energy Technology Data Exchange (ETDEWEB)

    Malerba, M.; De Angelis, F., E-mail: francesco.deangelis@iit.it [Istituto Italiano di Tecnologia, Via Morego, 30, I-16163 Genova (Italy); Ongarello, T.; Paulillo, B.; Manceau, J.-M.; Beaudoin, G.; Sagnes, I.; Colombelli, R., E-mail: raffaele.colombelli@u-psud.fr [Centre for Nanoscience and Nanotechnology (C2N Orsay), CNRS UMR9001, Univ. Paris Sud, Univ. Paris Saclay, 91405 Orsay (France)

    2016-07-11

    We report a crucial step towards single-object cavity electrodynamics in the mid-infrared spectral range using resonators that borrow functionalities from antennas. Room-temperature strong light-matter coupling is demonstrated in the mid-infrared between an intersubband transition and an extremely reduced number of sub-wavelength resonators. By exploiting 3D plasmonic nano-antennas featuring an out-of-plane geometry, we observed strong light-matter coupling in a very low number of resonators: only 16, more than 100 times better than what reported to date in this spectral range. The modal volume addressed by each nano-antenna is sub-wavelength-sized and it encompasses only ≈4400 electrons.

  11. All-semiconductor metamaterial-based optical circuit board at the microscale

    International Nuclear Information System (INIS)

    Min, Li; Huang, Lirong

    2015-01-01

    The newly introduced metamaterial-based optical circuit, an analogue of electronic circuit, is becoming a forefront topic in the fields of electronics, optics, plasmonics, and metamaterials. However, metals, as the commonly used plasmonic elements in an optical circuit, suffer from large losses at the visible and infrared wavelengths. We propose here a low-loss, all-semiconductor metamaterial-based optical circuit board at the microscale by using interleaved intrinsic GaAs and doped GaAs, and present the detailed design process for various lumped optical circuit elements, including lumped optical inductors, optical capacitors, optical conductors, and optical insulators. By properly combining these optical circuit elements and arranging anisotropic optical connectors, we obtain a subwavelength optical filter, which can always hold band-stop filtering function for various polarization states of the incident electromagnetic wave. All-semiconductor optical circuits may provide a new opportunity in developing low-power and ultrafast components and devices for optical information processing

  12. Properties of Sub-Wavelength Spherical Antennas With Arbitrarily Lossy Magnetodielectric Cores Approaching the Chu Lower Bound

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2014-01-01

    For a spherical antenna exciting any arbitrary spherical mode, we derive exact closed-form expressions for the dissipated power and stored energy inside (and outside) the lossy magneto-dielectric spherical core, as well as the radiated power, radiation efficiency, and thus the radiation quality...... an increasing magnetic loss tangent initially leads to a decreasing radiation quality factor, but in the limit of a perfect magnetic conductor (PMC) core the dissipated power tends to zero and the radiation quality factor reaches the fundamental Chu lower bound....

  13. Wireless measurement of elastic and plastic deformation by a metamaterial-based sensor.

    Science.gov (United States)

    Ozbey, Burak; Demir, Hilmi Volkan; Kurc, Ozgur; Erturk, Vakur B; Altintas, Ayhan

    2014-10-20

    We report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both the transmitter and the receiver. The NSRR probe is fixed on a standard steel reinforcing bar (rebar), and its frequency response is monitored telemetrically by a network analyzer connected to the antenna across the whole stress-strain curve. This wireless measurement includes both the elastic and plastic region deformation together for the first time, where wired technologies, like strain gauges, typically fail to capture. The experiments are further repeated in the presence of a concrete block between the antenna and the probe, and it is shown that the sensing system is capable of functioning through the concrete. The comparison of the wireless sensor measurement with those undertaken using strain gauges and extensometers reveals that the sensor is able to measure both the average strain and the relative displacement on the rebar as a result of the applied force in a considerably accurate way. The performance of the sensor is tested for different types of misalignments that can possibly occur due to the acting force. These results indicate that the metamaterial-based sensor holds great promise for its accurate, robust and wireless measurement of the elastic and plastic deformation of a rebar, providing beneficial information for remote structural health monitoring and post-earthquake damage assessment.

  14. Low-profile natural and metamaterial antennas analysis methods and applications

    CERN Document Server

    Nakano, Hisamatsu

    2017-01-01

    This book presents the full range of low-profile antennas that use novel elements and take advantage of new concepts in antenna implementation, including metamaterials. Typically formed by constructing lattices of simple elements, metamaterials possess electromagnetic properties not found in naturally occurring materials, and show great promise in a number of low-profile antenna implementations. Introductory chapters define various natural and metamaterial-based antennas and provide the fundamentals of writing computer programs based on the method of moments (MoM) and the finite-difference time-domain method (FDTDM). Chapters then discuss low-profile natural antennas classified into base station antennas, mobile card antennas, beam-forming antennas, and satellite-satellite and earth-satellite communications antennas. Final chapters look at various properties of low-profile metamaterial-based ant nnas, revealing the strengths and limitations of the metamaterial-based straight line antenna (metaline antenna), m...

  15. Local field effects and metamaterials based on colloidal quantum dots

    International Nuclear Information System (INIS)

    Porvatkina, O V; Tishchenko, A A; Strikhanov, M N

    2015-01-01

    Metamaterials are composite structures that exhibit interesting and unusual properties, e.g. negative refractive index. In this article we consider metamaterials based on colloidal quantum dots (CQDs). We investigate these structures taking into account the local field effects and theoretically analyze expressions for permittivity and permeability of metamaterials based on CdSe CQDs. We obtain inequality describing the conditions when material with definite concentration of CQDs is metamaterial. Also we investigate how the values of dielectric polarizability and magnetic polarizability of CQDs depend on the dots radius and properties the material the quantum dots are made of. (paper)

  16. A Microwave Method for Dielectric Characterization Measurement of Small Liquids Using a Metamaterial-Based Sensor.

    Science.gov (United States)

    Liu, Weina; Sun, Haoran; Xu, Lei

    2018-05-05

    We present a microwave method for the dielectric characterization of small liquids based on a metamaterial-based sensor The proposed sensor consists of a micro-strip line and a double split-ring resonator (SRR). A large electric field is observed on the two splits of the double SRRs at the resonance frequency (1.9 GHz). The dielectric property data of the samples under test (SUTs) were obtained with two measurements. One is with the sensor loaded with the reference liquid (REF) and the other is with the sensor loaded with the SUTs. Additionally, the principle of extracting permittivity from measured changes of resonance characteristics changes of the sensor loaded with REF and SUTs is given. Some measurements were carried out at 1.9 GHz, and the calculated results of methanol⁻water mixtures with different molar fractions agree well with the time-domain reflectometry method. Moreover, the proposed sensor is compact and highly sensitive for use of sub-wavelength resonance. In comparison with literature data, relative errors are less than 3% for the real parts and 2% for the imaginary parts of complex permittivity.

  17. Antennas.

    Science.gov (United States)

    1982-03-03

    arc csch csch - 1 Russian English rot curl lg log !i FIVE-METER SPHERICAL MILLIMETER-BAND ANTENNA P.M. Geruni This article presents the basic...rlpe’ I operating band, MHz elliptical Xk, mm X , m fk, MHz z wavgudeeg MHz f =1.2f f =0.95f waegid H X B rip = E40 104.5 56.4 2872 5410 3446 5141 E48...aperture In order to do this, we expand (30) into a series with respect to y. Limiting ourselves to the first three terms of the expansion, we obtain r

  18. A new metamaterial-based wideband rectangular invisibility cloak

    Science.gov (United States)

    Islam, S. S.; Hasan, M. M.; Faruque, M. R. I.

    2018-02-01

    A new metamaterial-based wideband electromagnetic rectangular cloak is being introduced in this study. The metamaterial unit cell shows sharp transmittances in the C- and X-bands and displays wideband negative effective permittivity region there. The metamaterial unit cell was then applied in designing a rectangular-shaped electromagnetic cloak. The scattering reduction technique was adopted for the cloaking operation. The cloak operates in the certain portion of C-and X-bands that covers more than 4 GHz bandwidth region. The experimental results were provided as well for the metamaterial and the cloak.

  19. Subwavelength resonant antennas enhancing electromagnetic energy harvesting

    Science.gov (United States)

    Oumbe Tekam, Gabin; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

    2016-04-01

    In this work, an electromagnetic energy harvester operating at microwave frequencies is designed based on a cut- wire metasurface. This metamaterial is known to contain a quasistatic electric dipole resonator leading to a strong resonant electric response when illuminated by electromagnetic fields.1 Starting from an equivalent electrical circuit, we analytically design the parameters of the system to tune the resonance frequency of the harvester at the desired frequency band. Subsequently, we compare these results with numerical simulations, which have been obtained using finite elements numerical simulations. Finally, we optimize the design by investigating the best arrangement for energy harvesting by coupling in parallel and in series many single layers of cut-wire metasurfaces. We also discuss the implementation of different geometries and sizes of the cut-wire metasurface for achieving different center frequencies and bandwidths.

  20. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  1. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    International Nuclear Information System (INIS)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens; Wollrab, Viktoria; Beigang, Rene; Rahm, Marco

    2012-01-01

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  2. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Wollrab, Viktoria; Beigang, Rene; Rahm, Marco [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Fraunhofer Institute for Physical Measurement Techniques IPM, 79110 Freiburg (Germany)

    2012-05-28

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  3. Symmetric metamaterials based on flower-shaped structure

    International Nuclear Information System (INIS)

    Tuong, P.V.; Park, J.W.; Rhee, J.Y.; Kim, K.W.; Cheong, H.; Jang, W.H.; Lee, Y.P.

    2013-01-01

    We proposed new models of metamaterials (MMs) based on a flower-shaped structure (FSS), whose “meta-atoms” consist of two flower-shaped metallic parts separated by a dielectric layer. Like the non-symmetric MMs based on cut-wire-pairs or electric ring resonators, the symmetrical FSS demonstrates the negative permeability at GHz frequencies. Employing the results, we designed a symmetric negative-refractive-index MM [a symmetric combined structure (SCS)], which is composed of FSSs and cross continuous wires. The MM properties of the FSS and the SCS are presented numerically and experimentally. - Highlights: • A new designed of sub-wavelength metamaterial, flower-shaped structure was proposed. • Flower-shaped meta-atom illustrated effective negative permeability. • Based on the meta-atom, negative refractive index was conventionally gained. • Negative refractive index was demonstrated with symmetric properties for electromagnetic wave. • Dimensional parameters were studied under normal electromagnetic wave

  4. Studies on omnidirectional enhancement of giga-hertz radiation by sub-wavelength plasma modulation

    Science.gov (United States)

    Fanrong, KONG; Qiuyue, NIE; Shu, LIN; Zhibin, WANG; Bowen, LI; Shulei, ZHENG; Binhao, JIANG

    2018-01-01

    The technology of radio frequency (RF) radiation intensification for radio compact antennas based on modulation and enhancement effects of sub-wavelength plasma structures represents an innovative developing strategy. It exhibits important scientific significance and promising potential of broad applications in various areas of national strategic demands, such as electrical information network and microwave communication, detection and control technology. In this paper, laboratory experiments and corresponding analyses have been carried out to investigate the modulation and enhancement technology of sub-wavelength plasma structure on the RF electromagnetic radiation. An application focused sub-wavelength plasma-added intensification up to ∼7 dB higher than the free-space radiation is observed experimentally in giga-hertz (GHz) RF band. The effective radiation enhancement bandwidth covers from 0.85 to 1.17 GHz, while the enhanced electromagnetic signals transmitted by sub-wavelength plasma structures maintain good communication quality. Particularly, differing from the traditional RF electromagnetic radiation enhancement method characterized by focusing the radiation field of antenna in a specific direction, the sub-wavelength plasma-added intensification of the antenna radiation presents an omnidirectional enhancement, which is reported experimentally for the first time. Corresponding performance characteristics and enhancement mechanism analyses are also conducted in this paper. The results have demonstrated the feasibility and promising potential of sub-wavelength plasma modulation in application focused RF communication, and provided the scientific basis for further research and development of sub-wavelength plasma enhanced compact antennas with wide-range requests and good quality for communication.

  5. Microwave Metamaterial-Based Sensor for Dielectric Characterization of Liquids.

    Science.gov (United States)

    Soffiatti, André; Max, Yuri; G Silva, Sandro; M de Mendonça, Laércio

    2018-05-11

    This article proposed to build a system founded on metamaterial sensor antennas, which can be used to evaluate impurities in aqueous substances according to the quality of transmission between the sensor antennas. In order to do this, a dedicated setup with tests in several frequencies was deployed so as to monitor the behavior of transmission variation between sensors. These sensors are microstrip antennas with a ground plane of resonant cleaved metallic rings; the substrate functions as a metamaterial for the irradiating element. In this study, an analysis was made of transmission between the sensors, looking for variation in angles of incidence of signal and of distance between the antennas. The sensor was tested at various operating frequencies, as such 1.8 GHz, 2.4 GHz, 3.4 GHz and 4.1 GHz, resulting in different values of sensitivity. The prototypes were constructed and tested so as to analyze the dielectric effects of the impurities on NaCl and C₂H₄O₂ substances. The research aims to use these control systems of impurities in industrial premises.

  6. Subwavelength Hyperlens Resolution With Perfect Contrast Function

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Repän, Taavi; Zhukovsky, Sergei

    2018-01-01

    , in principle, two sources standing apart at any subwavelength distance can be distinguished. We suggest two feasible designs, the first of which employs the obliquely incident light, while the second one is based on a properly designed metasurface. The concept can be used in high‐contrast subwavelength...

  7. Radio antennas

    Science.gov (United States)

    Gibson, S. W.

    This book is concerned with providing an explanation of the function of an antenna without delving too deeply into the mathematics or theory. The characteristics of an antenna are examined, taking into account aspects of antenna radiation, wave motion on the antenna, resistance in the antenna, impedance, the resonant antenna, the effect of the ground, polarization, radiation patterns, coupling effects between antenna elements, and receiving vs. transmitting. Aspects of propagation are considered along with the types of antennas, transmission lines, matching devices, questions of antenna design, antennas for the lower frequency bands, antennas for more than one band, limited space antennas, VHF antennas, and antennas for 20, 15, and 10 meters. Attention is given to devices for measuring antenna parameters, approaches for evaluating the antenna, questions of safety, and legal aspects.

  8. Electromagnetics of body area networks antennas, propagation, and RF systems

    CERN Document Server

    Werner, Douglas H

    2016-01-01

    The book is a comprehensive treatment of the field, covering fundamental theoretical principles and new technological advancements, state-of-the-art device design, and reviewing examples encompassing a wide range of related sub-areas. In particular, the first area focuses on the recent development of novel wearable and implantable antenna concepts and designs including metamaterial-based wearable antennas, microwave circuit integrated wearable filtering antennas, and textile and/or fabric material enabled wearable antennas. The second set of topics covers advanced wireless propagation and the associated statistical models for on-body, in-body, and off-body modes. Other sub-areas such as efficient numerical human body modeling techniques, artificial phantom synthesis and fabrication, as well as low-power RF integrated circuits and related sensor technology are also discussed. These topics have been carefully selected for their transformational impact on the next generation of body-area network systems and beyo...

  9. Broadband tunable electromagnetically induced transparency analogue metamaterials based on graphene in terahertz band

    Science.gov (United States)

    Wang, Yue; Leng, Yanbing; Wang, Li; Dong, Lianhe; Liu, Shunrui; Wang, Jun; Sun, Yanjun

    2018-06-01

    Most of the actively controlled electromagnetically induced transparency analogue (EIT-like) metamaterials were implemented with narrowband modulations. In this paper, a broadband tunable EIT-like metamaterial based on graphene in the terahertz band is presented. It consists of a cut wire as the bright resonator and two couples of H-shaped resonators in mirror symmetry as the dark resonators. A broadband tunable property of transmission amplitude is realized by changing the Fermi level of graphene. Furthermore, the geometries of the metamaterial structure are optimized to achieve the ideal curve through the simulation. Such EIT-like metamaterials proposed here are promising candidates for designing active wide-band slow-light devices, wide-band terahertz active filters, and wide-band terahertz modulators.

  10. Metamaterials-based sensor to detect and locate nonlinear elastic sources

    Energy Technology Data Exchange (ETDEWEB)

    Gliozzi, Antonio S.; Scalerandi, Marco [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Miniaci, Marco; Bosia, Federico [Department of Physics, University of Torino, Via Pietro Giuria 1, 10125 Torino (Italy); Pugno, Nicola M. [Laboratory of Bio-Inspired and Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Center for Materials and Microsystems, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (Trento) (Italy); School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2015-10-19

    In recent years, acoustic metamaterials have attracted increasing scientific interest for very diverse technological applications ranging from sound abatement to ultrasonic imaging, mainly due to their ability to act as band-stop filters. At the same time, the concept of chaotic cavities has been recently proposed as an efficient tool to enhance the quality of nonlinear signal analysis, particularly in the ultrasonic/acoustic case. The goal of the present paper is to merge the two concepts in order to propose a metamaterial-based device that can be used as a natural and selective linear filter for the detection of signals resulting from the propagation of elastic waves in nonlinear materials, e.g., in the presence of damage, and as a detector for the damage itself in time reversal experiments. Numerical simulations demonstrate the feasibility of the approach and the potential of the device in providing improved signal-to-noise ratios and enhanced focusing on the defect locations.

  11. Metamaterials-based sensor to detect and locate nonlinear elastic sources

    International Nuclear Information System (INIS)

    Gliozzi, Antonio S.; Scalerandi, Marco; Miniaci, Marco; Bosia, Federico; Pugno, Nicola M.

    2015-01-01

    In recent years, acoustic metamaterials have attracted increasing scientific interest for very diverse technological applications ranging from sound abatement to ultrasonic imaging, mainly due to their ability to act as band-stop filters. At the same time, the concept of chaotic cavities has been recently proposed as an efficient tool to enhance the quality of nonlinear signal analysis, particularly in the ultrasonic/acoustic case. The goal of the present paper is to merge the two concepts in order to propose a metamaterial-based device that can be used as a natural and selective linear filter for the detection of signals resulting from the propagation of elastic waves in nonlinear materials, e.g., in the presence of damage, and as a detector for the damage itself in time reversal experiments. Numerical simulations demonstrate the feasibility of the approach and the potential of the device in providing improved signal-to-noise ratios and enhanced focusing on the defect locations

  12. Evidence for subwavelength imaging with positive refraction

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yun Gui [Temasek Laboratories, National University of Singapore, Singapore 119260 (Singapore); Sahebdivan, Sahar; Tyc, Tomas; Leonhardt, Ulf [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Ong, C K, E-mail: ulf@st-andrews.ac.uk [Centre for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, Singapore 117542 (Singapore)

    2011-03-15

    The resolution of lenses is normally limited by the wave nature of light. Imaging with perfect resolution was believed to rely on negative refraction, but here we present experimental evidence for subwavelength imaging with positive refraction.

  13. Evidence for subwavelength imaging with positive refraction

    International Nuclear Information System (INIS)

    Ma, Yun Gui; Sahebdivan, Sahar; Tyc, Tomas; Leonhardt, Ulf; Ong, C K

    2011-01-01

    The resolution of lenses is normally limited by the wave nature of light. Imaging with perfect resolution was believed to rely on negative refraction, but here we present experimental evidence for subwavelength imaging with positive refraction.

  14. Evidence for subwavelength imaging with positive refraction

    OpenAIRE

    Ma, Yun Gui; Sahebdivan, Sahar; Ong, C. K.; Tyc, Tomas; Leonhardt, Ulf

    2011-01-01

    The resolution of lenses is normally limited by the wave nature of light. Imaging with perfect resolution was believed to rely on negative refraction, but here we present experimental evidence for subwavelength imaging with positive refraction. Publisher PDF Peer reviewed

  15. Plasmonic-Resonant Bowtie Antenna for Carbon Nanotube Photodetectors

    Directory of Open Access Journals (Sweden)

    Hongzhi Chen

    2012-01-01

    Full Text Available The design of bowtie antennas for carbon nanotube (CNT photodetectors has been investigated. CNT photodetectors have shown outstanding performance by using CNT as sensing element. However, detection wavelength is much larger than the diameter of the CNT, resulting in small fill factor. Bowtie antenna can confine light into a subwavelength volume based on plasmonic resonance, thus integrating a bowtie antenna to CNT photodetectors can highly improve photoresponse of the detectors. The electric field enhancement of bowtie antennas was calculated using the device geometry by considering fabrication difficulties and photodetector structure. It is shown that the electric field intensity enhancement increased exponentially with distance reduction between the CNT photodetector to the antenna. A redshift of the peak resonance wavelength is predicted due to the increase of tip angles of the bowtie antennas. Experimental results showed that photocurrent enhancement agreed well with theoretical calculations. Bowtie antennas may find wide applications in nanoscale photonic sensors.

  16. A Brief Review on Metamaterial-Based Vacuum Electronics for Terahertz and Microwave Science and Technology

    Science.gov (United States)

    Matsui, Tatsunosuke

    2017-09-01

    Metamaterials, which enable us to realize novel physical effects that cannot be achieved using natural materials, have been extensively studied in recent years and significant progress has been made, especially in the field of optics. This game-changing concept has also initiated a rich variety of research activity in vacuum electronics. Here we review the recent development of metamaterial-based vacuum electronics for terahertz (THz) and microwave science and technology. The reversed Cherenkov radiation (RCR) in double-negative (DNG) metamaterials predicted by Veselago back in the 1960s has been experimentally verified in the microwave frequency range by utilizing specially designed DNG metamaterials. The interaction of an electron beam (e-beam) with DNG metamaterials may lead to the realization of novel applications such as microwave and THz radiation sources, accelerators, and even the visualization of invisibility cloaks. Smith-Purcell radiation (SPR) has recently received renewed interest owing to the development of metamaterials and the concept of spoof surface plasmon polaritons, as discussed in this review, and recent results on e-beam-induced directional and wide-band THz radiation with sharp multiple peaks from a graded grating, as well as directional and monochromatic special SPR and their possible application to THz orotron devices, are also reviewed.

  17. Progress in surface plasmon subwavelength optics

    International Nuclear Information System (INIS)

    Zhang Douguo; Wang Pei; Jiao Xiaojin; Tang Lin; Lu Yonghua; Ming Hai

    2005-01-01

    Now great attention is being paid to the potential applications of surface plasmon polaritons (SPPs) in data storage, light generation, microscopy and bio-photonics. The authors review the properties of SPPs and topics of recent interest in surface plasmon subwavelength optics. (author)

  18. Subwavelength nanopatterning of photochromic diarylethene films

    Energy Technology Data Exchange (ETDEWEB)

    Cantu, Precious; Brimhall, Nicole; Menon, Rajesh [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Andrew, Trisha L. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Castagna, Rossella; Bertarelli, Chiara [Dipartimento di Chimica, Materiali e Ingegneria Chimica ' ' Giulio Natta' ' , Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano (Italy); Center for Nano Science and Technology - PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy)

    2012-04-30

    The resolution of optical patterning is constrained by the far-field diffraction limit. In this letter, we describe an approach that exploits the unique photo- and electro-chemistry of diarylethene photochromic molecules to overcome this diffraction limit and achieve sub-wavelength nanopatterning.

  19. Resolution revival technique for subwavelength imaging

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Repän, Taavi; Zhukovsky, Sergei

    2017-01-01

    The method to achieve a high resolution of subwavelength features (to improve the contrast function) for a dark-field hyperlens—hyperbolic metamaterial slab possessing metallic properties at the interface — is developed. The technique requires the introduction of the phase difference between the o...

  20. Disorder effects in subwavelength grating metamaterial waveguides

    Czech Academy of Sciences Publication Activity Database

    Ortega-Moñux, A.; Čtyroký, Jiří; Cheben, P.; Schmid, J. H.; Wang, S.; Molina-Fernández, I.; Halíř, R.

    2017-01-01

    Roč. 25, č. 11 (2017), s. 12222-12236 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GA16-00329S Institutional support: RVO:67985882 Keywords : Subwavelength grating * Integrated photonics * Diffraction effects Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 3.307, year: 2016

  1. Subwavelength light confinement with surface plasmon polaritons

    NARCIS (Netherlands)

    Verhagen, E.

    2009-01-01

    In free space, the diffraction limit sets a lower bound to the size to which light can be confined. Surface plasmon polaritons (SPPs), which are electromagnetic waves bound to the interface between a metal and a dielectric, allow the control of light on subwavelength length scales. This opens up a

  2. Magnetic Properties and Phase Composition of Metamaterials Based on an Opal Matrix with 3 d-Transition Metal Particles

    Science.gov (United States)

    Rinkevich, A. B.; Korolev, A. V.; Samoilovich, M. I.; Perov, D. V.; Nemytova, O. V.

    2018-02-01

    The magnetic properties of metamaterials based on an opal matrix with transition-metal (iron, nickel, cobalt) particles have been studied. Magnetization curves and magnetic hysteresis loops have been measured and the dependences of real and imaginary parts of magnetization have been determined using the dynamic ac susceptibility measuring procedure. Structural studies of metamaterials have been performed. The saturation magnetization and coercive force of the studied metamaterials have been found to depend weakly on the temperature. The temperature dependence of magnetic susceptibility at a temperature above 30 K can be described adequately by Curie-Weiss law and, at lower temperature, deviates from the law.

  3. Dielectric optical antenna thermal emitters and metamaterials

    Science.gov (United States)

    Schuller, Jonathan Aaron

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this thesis, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial. We further show that these particles can serve as "broadcasting" antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas.

  4. Dielectric Optical Antenna Emitters and Metamaterials

    Science.gov (United States)

    Schuller, Jon

    2009-03-01

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this talk, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial [1]. We further show that these particles can serve as ``broadcasting'' antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas and discuss extensions of the demonstrated concepts to different materials systems and frequency regimes. [1] J.A. Schuller, et al., Phys. Rev. Lett. 99, 107401 (2007)

  5. Analysis of a Waveguide-Fed Metasurface Antenna

    Science.gov (United States)

    Smith, David R.; Yurduseven, Okan; Mancera, Laura Pulido; Bowen, Patrick; Kundtz, Nathan B.

    2017-11-01

    The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wave-front shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The metasurface antenna consists of an array of metamaterial elements distributed over an electrically large structure, each subwavelength in dimension and with subwavelength separation between elements. In the antenna configuration we consider, the metasurface is excited by the fields from an attached waveguide. Each metamaterial element can be modeled as a polarizable dipole that couples the waveguide mode to radiation modes. Distinct from the phased array and electronically-scanned-antenna architectures, a dynamic metasurface antenna does not require active phase shifters and amplifiers but rather achieves reconfigurability by shifting the resonance frequency of each individual metamaterial element. We derive the basic properties of a one-dimensional waveguide-fed metasurface antenna in the approximation in which the metamaterial elements do not perturb the waveguide mode and are noninteracting. We derive analytical approximations for the array factors of the one-dimensional antenna, including the effective polarizabilities needed for amplitude-only, phase-only, and binary constraints. Using full-wave numerical simulations, we confirm the analysis, modeling waveguides with slots or complementary metamaterial elements patterned into one of the surfaces.

  6. Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting.

    Science.gov (United States)

    Kim, Soo Jin; Kang, Ju-Hyung; Mutlu, Mehmet; Park, Joonsuk; Park, Woosung; Goodson, Kenneth E; Sinclair, Robert; Fan, Shanhui; Kik, Pieter G; Brongersma, Mark L

    2018-01-22

    The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons.

  7. Investigation of the effects of metal-wire resonators in sub-wavelength array based on time-reversal technique

    International Nuclear Information System (INIS)

    Tu, Hui-Lin; Xiao, Shao-Qiu

    2016-01-01

    The resonant metalens consisting of metal-wire resonators with equally finite length can break the diffraction barrier well suited for super-resolution imaging. In this study, a basic combination constructed by two metal-wire resonators with different lengths is proposed, and its resonant characteristics is analyzed using the method of moments (MoM). Based on the time reversal (TR) technique, this kind of combination can be applied to a sub-wavelength two-element antenna array with a 1/40-wavelength interval to make the elements work simultaneously with little interference in the frequency band of 1.0-1.5 GHz and 1.5-2.0 GHz, respectively. The simulations and experiments show that analysis of MoM and the application of the resonators can be used to design multi-frequency sub-wavelength antenna arrays efficiently. This general design method is convenient and can be used for many applications, such as weakening jamming effectiveness in communication systems, and sub-wavelength imaging in a broad frequency band.

  8. Optical spatial differentiator based on subwavelength high-contrast gratings

    Science.gov (United States)

    Dong, Zhewei; Si, Jiangnan; Yu, Xuanyi; Deng, Xiaoxu

    2018-04-01

    An optical spatial differentiator based on subwavelength high-contrast gratings (HCGs) is proposed experimentally. The spatial differentiation property of the subwavelength HCG is analyzed by calculating its spatial spectral transfer function based on the periodic waveguide theory. By employing the FDTD solutions, the performance of the subwavelength HCG spatial differentiator was investigated numerically. The subwavelength HCG differentiator with the thickness at the nanoscale was fabricated on the quartz substrate by electron beam lithography and Bosch deep silicon etching. Observed under an optical microscope with a CCD camera, the spatial differentiation of the incident field profile was obtained by the subwavelength HCG differentiator in transmission without Fourier lens. By projecting the images of slits, letter "X," and a cross on the subwavelength HCG differentiator, edge detections of images were obtained in transmission. With the nanoscale HCG structure and simple optical implementation, the proposed optical spatial differentiator provides the prospects for applications in optical computing systems and parallel data processing.

  9. Antenna toolkit

    CERN Document Server

    Carr, Joseph

    2006-01-01

    Joe Carr has provided radio amateurs and short-wave listeners with the definitive design guide for sending and receiving radio signals with Antenna Toolkit 2nd edition.Together with the powerful suite of CD software, the reader will have a complete solution for constructing or using an antenna - bar the actual hardware! The software provides a simple Windows-based aid to carrying out the design calculations at the heart of successful antenna design. All the user needs to do is select the antenna type and set the frequency - a much more fun and less error prone method than using a con

  10. An extraordinary transmission analogue for enhancing microwave antenna performance

    Directory of Open Access Journals (Sweden)

    Sarin V. Pushpakaran

    2015-10-01

    Full Text Available The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.

  11. Metamaterial-based half Maxwell fish-eye lens for broadband directive emissions

    Science.gov (United States)

    Dhouibi, Abdallah; Nawaz Burokur, Shah; de Lustrac, André; Priou, Alain

    2013-01-01

    The broadband directive emission from a metamaterial surface is numerically and experimentally reported. The metasurface, composed of non-resonant complementary closed ring structures, is designed to obey the refractive index of a half Maxwell fish-eye lens. A planar microstrip Vivaldi antenna is used as transverse magnetic polarized wave launcher for the lens. A prototype of the lens associated with its feed structure has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Measurements agree quantitatively and qualitatively with theoretical simulations.

  12. Local and dynamic properties of light interacting with subwavelength holes

    NARCIS (Netherlands)

    Prangsma, Jord

    2009-01-01

    The discovery of the extraordinary transmission phenomena has initiated an intense study of the interaction of light with subwavelength holes. In this thesis the dynamic and local properties of light interacting with subwavelength holes are investigated. First of all the role of hole shape on the

  13. Sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2008-01-01

    It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...

  14. Sub-wavelength imaging at radio frequency

    International Nuclear Information System (INIS)

    Wiltshire, M C K; Pendry, J B; Hajnal, J V

    2006-01-01

    A slab of material with a negative permeability can act as a super-lens for magnetic fields and generate images with a sub-wavelength resolution. We have constructed an effective medium using a metamaterial with negative permeability in the region of 24 MHz, and used this to form images in free space of radio frequency magnetic sources. Measurements of these images show that a resolution of approximately λ/64 has been achieved, consistent with both analytical and numerical predictions. (letter to the editor)

  15. Subwavelength terahertz imaging with graphene hyperlens

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei

    2012-01-01

    ) [2]. Direct scaling of optical designs to the THz range is not possible, since metal’s negative permittivity becomes too large in absolute value. This is why the employment of new materials is required. In this contribution we report for the first time the graphene wire medium based hyperlens....... Stacking multiple structured graphene layers provides the hyperbolic dispersion. To restore the graphene wire medium dispersion diagrams and isofrequency contours we developed a rigorous numerical method. It also gives the possibility to calculate the permittivity tensor and to check the applicability...... of the homogeneous medium approach. Our numerical simulations in COMSOL and CST Microwave Studio confirm the subwavelength imaging properties of the graphene hyperlens. An example of magnification of two point sources separated by λ/5 to the size of few wavelength, which then can be detected with conventional optics...

  16. Subwavelength atom localization via coherent population trapping

    International Nuclear Information System (INIS)

    Agarwal, G S; Kapale, K T

    2006-01-01

    We present an atom localization scheme based on coherent population trapping. We consider atomic transitions in a Lambda configuration where the control field is a standing-wave field. The probe field and the control field produce coherence between the two ground states and prepare the atom in a pure state. We show that the population in one of the ground states has the same fringe pattern as produced by a Fabry-Perot interferometer and thus measurement of this population would localize the atom. Interestingly enough the role of the cavity finesse is played by the ratio of the intensities of the pump and probe. This is in fact the reason for obtaining extreme subwavelength localization

  17. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  18. Extreme localization of light with femtosecond subwavelength rogue waves

    KAUST Repository

    Liu, Changxu

    2015-01-01

    By using theory and experiments, we investigate a new mechanism based on spontaneous synchronization of random waves which generates ultrafast subwavelength rare events in integrated photonic chips. © 2014 Optical Society of America.

  19. Out-of-plane reflection and refraction of light by anisotropic optical antenna metasurfaces with phase discontinuities.

    Science.gov (United States)

    Aieta, Francesco; Genevet, Patrice; Yu, Nanfang; Kats, Mikhail A; Gaburro, Zeno; Capasso, Federico

    2012-03-14

    Experiments on ultrathin anisotropic arrays of subwavelength optical antennas display out-of-plane refraction. A powerful three-dimensional (3D) extension of the recently demonstrated generalized laws of refraction and reflection shows that the interface imparts a tangential wavevector to the incident light leading to anomalous beams, which in general are noncoplanar with the incident beam. The refracted beam direction can be controlled by varying the angle between the plane of incidence and the antenna array. © 2012 American Chemical Society

  20. Microstructured gradient-index lenses for THz photoconductive antennas

    Directory of Open Access Journals (Sweden)

    Mads Brincker

    2016-02-01

    Full Text Available A new type of substrate lens for photoconductive antennas (PCA’s based on sub-wavelength microstructuring is presented and studied theoretically by the use of Greens function integral equation methods (GFIEM’s. By etching sub-wavelength trenches into a flat substrate, the effective dielectric constant can be designed to function like a gradient index (GRIN lens. The proposed GRIN substrate lenses have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL, and could enable fabrication of arrays of closely packed PCA’s with individual lenses integrated directly into the PCA substrate. The performance of different GRIN lenses is compared to a HSL and shown to be comparable with regards to the terahertz radiation extraction efficiency, and it is shown that the collimating properties of these GRIN lenses can be tailored by changing the parameters used for microstructuring.

  1. Subwavelength resolution from multilayered structure (Conference Presentation)

    Science.gov (United States)

    Cheng, Bo Han; Jen, Yi-Jun; Liu, Wei-Chih; Lin, Shan-wen; Lan, Yung-Chiang; Tsai, Din Ping

    2016-10-01

    Breaking optical diffraction limit is one of the most important issues needed to be overcome for the demand of high-density optoelectronic components. Here, a multilayered structure which consists of alternating semiconductor and dielectric layers for breaking optical diffraction limitation at THz frequency region are proposed and analyzed. We numerically demonstrate that such multilayered structure not only can act as a hyperbolic metamaterial but also a birefringence material via the control of the external temperature (or magnetic field). A practical approach is provided to control all the diffraction signals toward a specific direction by using transfer matrix method and effective medium theory. Numerical calculations and computer simulation (based on finite element method, FEM) are carried out, which agree well with each other. The temperature (or magnetic field) parameter can be tuned to create an effective material with nearly flat isofrequency feature to transfer (project) all the k-space signals excited from the object to be resolved to the image plane. Furthermore, this multilayered structure can resolve subwavelength structures at various incident THz light sources simultaneously. In addition, the resolution power for a fixed operating frequency also can be tuned by only changing the magnitude of external magnetic field. Such a device provides a practical route for multi-functional material, photolithography and real-time super-resolution image.

  2. Localization noise in deep subwavelength plasmonic devices

    Science.gov (United States)

    Ghoreyshi, Ali; Victora, R. H.

    2018-05-01

    The grain shape dependence of absorption has been investigated in metal-insulator thin films. We demonstrate that randomness in the size and shape of plasmonic particles can lead to Anderson localization of polarization modes in the deep subwavelength regime. These localized modes can contribute to significant variation in the local field. In the case of plasmonic nanodevices, the effects of the localized modes have been investigated by mapping an electrostatic Hamiltonian onto the Anderson Hamiltonian in the presence of a random vector potential. We show that local behavior of the optical beam can be understood in terms of the weighted local density of the localized modes of the depolarization field. Optical nanodevices that operate on a length scale with high variation in the density of states of localized modes will experience a previously unidentified localized noise. This localization noise contributes uncertainty to the output of plasmonic nanodevices and limits their scalability. In particular, the resulting impact on heat-assisted magnetic recording is discussed.

  3. Superluminal antenna

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, John; Earley, Lawrence M.; Krawczyk, Frank L.; Potter, James M.; Romero, William P.; Wang, Zhi-Fu

    2018-04-17

    A superluminal antenna element integrates a balun element to better impedance match an input cable or waveguide to a dielectric radiator element, thus preventing stray reflections and consequent undesirable radiation. For example, a dielectric housing material can be used that has a cutout area. A cable can extend into the cutout area. A triangular conductor can function as an impedance transition. An additional cylindrical element functions as a sleeve balun to better impedance match the radiator element to the cable.

  4. Broadband standard dipole antenna for antenna calibration

    Science.gov (United States)

    Koike, Kunimasa; Sugiura, Akira; Morikawa, Takao

    1995-06-01

    Antenna calibration of EMI antennas is mostly performed by the standard antenna method at an open-field test site using a specially designed dipole antenna as a reference. In order to develop broadband standard antennas, the antenna factors of shortened dipples are theoretically investigated. First, the effects of the dipole length are analyzed using the induced emf method. Then, baluns and loads are examined to determine their influence on the antenna factors. It is found that transformer-type baluns are very effective for improving the height dependence of the antenna factors. Resistive loads are also useful for flattening the frequency dependence. Based on these studies, a specification is developed for a broadband standard antenna operating in the 30 to 150 MHz frequency range.

  5. Nanometers to centimeters: novel optical nano-antennas, with an eye to scaled production

    Science.gov (United States)

    James, Timothy D.; Cadusch, Jasper J.; Earl, Stuart K.; Panchenko, Evgeniy; Mulvaney, Paul; Davis, Timothy J.; Roberts, Ann

    2016-03-01

    Optical nano-antennas have been the focus of intense research recently due to their ability to manipulate electromagnetic radiation on a subwavelength scale, and there is major interest in such devices for a wide variety of applications in photonics, sensing, and imaging. Significant effort has been put into developing highly compact, novel, next-generation light sources, which have great potential in realizing efficient sub-wavelength single photon sources and enhanced biological and chemical sensors. We have developed a number of innovative optical antenna designs including elements of chiral metasurfaces for enabling circularly polarized emission from quantum sources, new designs derived from Radio Frequency (RF) elements for quantum source enhancement and directionality, and nanostructures for investigating plasmonic dark-modes that have the ability to significantly reduce the Q-factor of nano-antennas. A challenge, however, remains the development of a scalable nanofabrication technology. The capacity to mass-produce nano-antennas will have a considerable impact on the commercial viability of these devices, and greatly improve research throughput. Here we present recent progress in the development of scalable fabrication strategies for producing of nano-antennas and antenna arrays, along with slot based plasmonic optical devices.

  6. A unidirectional subwavelength focusing near-field plate

    Energy Technology Data Exchange (ETDEWEB)

    Imani, Mohammadreza F.; Grbic, Anthony [Radiation Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-01-28

    Near-field plates consist of non-periodically patterned surfaces that can overcome the diffraction limit and confine electromagnetic fields to subwavelength dimensions. Previous near-field plates experimentally demonstrated extreme field tailoring capabilities. However, their performance suffered from radiation/reflection in undesired directions, those other than the subwavelength focus. This issue can limit the practical use of near-field plates. In this paper, we address this issue by designing a unidirectional near-field plate that can form a subwavelength focal pattern, while suppressing the field radiated/reflected in other directions. The design and operation of the proposed unidirectional near-field plate are verified through full-wave simulation. The unidirectional near-field plate may find application in high resolution imaging and probing, high density data storage, and wireless power transfer systems. As an example, its utility as a high resolution probe is demonstrated through full-wave electromagnetic simulation.

  7. Transmission of electromagnetic waves through sub-wavelength channels

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Luo, Yu; Mortensen, Asger

    2010-01-01

    We propose a method of tunneling electromagnetic (EM) waves through a channel with sub-wavelength cross section. By filling the channel with high-ε isotropic material and implementing two matching layers with uniaxial metamterial substrates, the guided waves can go through the narrow channel...... without being cut off, as if it has just passed through the original empty waveguide. Both the magnitude and phase information of the EM fields can be effectively restored after passing this channel, regardless of the polarization of the incoming wave. The performance of this subwavelength channel, which...

  8. Enhanced terahertz magnetic dipole response by subwavelength fiber

    DEFF Research Database (Denmark)

    Atakaramians, Shaghik; Shadrivov, Ilya V.; Miroshnichenko, Andrey E.

    2018-01-01

    Dielectric sub-wavelength particles have opened up a new platform for realization of magnetic light. Recently, we have demonstrated that a dipole emitter by a sub-wavelength fiber leads to an enhanced magnetic response. Here, we experimentally demonstrate an enhanced magnetic dipole source......-fiber system excited by a magnetic source. This coupled magnetic dipole and optical fiber system can be considered a unit cell of metasurfaces for manipulation of terahertz radiation and is a proof-of-concept of a possibility to achieve enhanced radiation of a dipole source in proximity of a sub...

  9. Subwavelength image manipulation through oblique and herringbone layered acoustic systems

    International Nuclear Information System (INIS)

    Li, Chunhui; Jia, Han; Ke, Manzhu; Li, Yixiang; Liu, Zhengyou

    2014-01-01

    In this paper, an oblique and a herringbone layered acoustic structure are experimentally and theoretically demonstrated to manipulate acoustic subwavelength images. An imaging resolution of less than one tenth of a wavelength is achieved with both optimized systems, and lateral image shift has been realized by an oblique layered system. The thicknesses of both the oblique and the herringbone layered acoustic systems are largely reduced through utilizing the oblique or herringbone wave propagation path instead of the vertical wave propagation path in the rectangular layered planar acoustic system. With smaller size and subwavelength image manipulation, the acoustic systems are more favourable for practical application. (paper)

  10. Antennas in inhomogeneous media

    CERN Document Server

    Galejs, Janis; Fock, V A; Wait, J R

    2013-01-01

    Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

  11. Retrieval of Effective Parameters of Subwavelength Periodic Photonic Structures

    DEFF Research Database (Denmark)

    Orlov, Alexey A.; Yankovskaya, Elizaveta A.; Zhukovsky, Sergei

    2014-01-01

    We revisit the standard Nicolson Ross Weir method of effective permittivity and permeability restoration of photonic structures for the case of subwavelength metal-dielectric multilayers. We show that the direct application of the standard method yields a false zero-epsilon point and an associated...

  12. Inhibited emission of electromagnetic modes confined in subwavelength cavities

    International Nuclear Information System (INIS)

    Le Thomas, N.; Houdre, R.

    2011-01-01

    We experimentally demonstrate the active inhibition of subwavelength confined cavity modes emission and quality factor enhancement by controlling the cavity optical surrounding. The intrinsic radiation angular spectrum of modes confined in planar photonics crystal cavities as well as its modifications depending on the environment are inferred via a transfer matrix modeling and k-space imaging.

  13. 1060-nm Tunable Monolithic High Index Contrast Subwavelength Grating VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta

    2013-01-01

    We present the first tunable vertical-cavity surface-emitting laser (VCSEL) where the top distributed Bragg reflector has been completely substituted by an air-cladded high-index-contrast subwavelength grating (HCG) mirror. In this way, an extended cavity design can be realized by reducing...

  14. Sub-wavelength metamaterial cylinders with multiple dipole resonances

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM...... configuration thus offer the possibility for multi-resonant electrically small configurations....

  15. Controlling the near-field excitation of nano-antennas with phase-change materials.

    Science.gov (United States)

    Kao, Tsung Sheng; Chen, Yi Guo; Hong, Ming Hui

    2013-01-01

    By utilizing the strongly induced plasmon coupling between discrete nano-antennas and quantitatively controlling the crystalline proportions of an underlying Ge2Sb2Te5 (GST) phase-change thin layer, we show that nanoscale light localizations in the immediate proximity of plasmonic nano-antennas can be spatially positioned. Isolated energy hot-spots at a subwavelength scale can be created and adjusted across the landscape of the plasmonic system at a step resolution of λ/20. These findings introduce a new approach for nano-circuitry, bio-assay addressing and imaging applications.

  16. Split Bull's eye shaped aluminum antenna for plasmon-enhanced nanometer scale germanium photodetector.

    Science.gov (United States)

    Ren, Fang-Fang; Ang, Kah-Wee; Ye, Jiandong; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2011-03-09

    Bull's eye antennas are capable of efficiently collecting and concentrating optical signals into an ultrasmall area, offering an excellent solution to break the bottleneck between speed and photoresponse in subwavelength photodetectors. Here, we exploit the idea of split bull's eye antenna for a nanometer germanium photodetector operating at a standard communication wavelength of 1310 nm. The nontraditional plasmonic metal aluminum has been implemented in the resonant antenna structure fabricated by standard complementary metal-oxide-semiconductor (CMOS) processing. A significant enhancement in photoresponse could be achieved over the conventional bull's eye scheme due to an increased optical near-field in the active region. Moreover, with this novel antenna design the effective grating area could be significantly reduced without sacrificing device performance. This work paves the way for the future development of low-cost, high-density, and high-speed CMOS-compatible germanium-based optoelectronic devices.

  17. Optical Nano-antennae as Compact and Efficient Couplers from Free-space to Waveguide Modes

    DEFF Research Database (Denmark)

    Zenin, Vladimir A.; Malureanu, Radu; Volkov, Valentyn

    2015-01-01

    Optical nano-antennae are one of the possible solutions for coupling free-space radiation into subwavelength waveguides. Our efforts were concentrated on coupling between an optical fibre and a plasmonic slot waveguide. Such coupling is still an issue to be solved in order to advance the use...... of plasmonic waveguides for optical interconnects. During the talk, we will present our modelling optimisation, fabrication and measurement of the nano-antennae functionality. For the modelling part, we used CST Microwave studio for optimising the antenna geometry. Various antennae were modelled and fabricated....... The fabrication was based on electron beam lithography and lift-off processes. The measurements were performed with scattering scanning near-field microscope and allowed the retrieval of both amplitude and phase of the propagating plasmon. The obtained values agree very well with the theoretically predicted ones...

  18. Plasma antennas: dynamically configurable antennas for communications

    International Nuclear Information System (INIS)

    Borg, G.; Harris, J.

    1999-01-01

    In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility. For military applications, antennas should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun worldwide on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. A recent patent for ground penetrating radar claims the invention of a plasma antenna for the transmission of pulses shorter than 100 ns in which it is claimed that current ringing is avoided and signal processing simplified compared with a metal antenna. A recent US ONR tender has been issued for the design and construction of a compact and rapidly reconfigurable antenna for dynamic signal reception over the frequency range 1 - 45 GHz based on plasma antennas. Recent basic physics experiments at ANU have demonstrated that plasma antennas can attain adequate efficiency, predictable radiation patterns and low base-band noise for HF and VHF communications. In this paper we describe the theory of the low frequency plasma antenna and present a few experimental results

  19. Metamaterial-based transmit and receive system for whole-body magnetic resonance imaging at ultra-high magnetic fields.

    Science.gov (United States)

    Herrmann, Tim; Liebig, Thorsten; Mallow, Johannes; Bruns, Christian; Stadler, Jörg; Mylius, Judith; Brosch, Michael; Svedja, Jan Taro; Chen, Zhichao; Rennings, Andreas; Scheich, Henning; Plaumann, Markus; Hauser, Marcus J B; Bernarding, Johannes; Erni, Daniel

    2018-01-01

    Magnetic resonance imaging (MRI) at ultra-high fields (UHF), such as 7 T, provides an enhanced signal-to-noise ratio and has led to unprecedented high-resolution anatomic images and brain activation maps. Although a variety of radio frequency (RF) coil architectures have been developed for imaging at UHF conditions, they usually are specialized for small volumes of interests (VoI). So far, whole-body coil resonators are not available for commercial UHF human whole-body MRI systems. The goal of the present study was the development and validation of a transmit and receive system for large VoIs that operates at a 7 T human whole-body MRI system. A Metamaterial Ring Antenna System (MRAS) consisting of several ring antennas was developed, since it allows for the imaging of extended VoIs. Furthermore, the MRAS not only requires lower intensities of the irradiated RF energy, but also provides a more confined and focused injection of excitation energy on selected body parts. The MRAS consisted of several antennas with 50 cm inner diameter, 10 cm width and 0.5 cm depth. The position of the rings was freely adjustable. Conformal resonant right-/left-handed metamaterial was used for each ring antenna with two quadrature feeding ports for RF power. The system was successfully implemented and demonstrated with both a silicone oil and a water-NaCl-isopropanol phantom as well as in vivo by acquiring whole-body images of a crab-eating macaque. The potential for future neuroimaging applications was demonstrated by the acquired high-resolution anatomic images of the macaque's head. Phantom and in vivo measurements of crab-eating macaques provided high-resolution images with large VoIs up to 40 cm in xy-direction and 45 cm in z-direction. The results of this work demonstrate the feasibility of the MRAS system for UHF MRI as proof of principle. The MRAS shows a substantial potential for MR imaging of larger volumes at 7 T UHF. This new technique may provide new diagnostic potential

  20. Terahertz spoof surface-plasmon-polariton subwavelength waveguide

    KAUST Repository

    Zhang, Ying; Xu, Yuehong; Tian, Chunxiu; Xu, Quan; Zhang, Xueqian; Li, Yanfeng; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2017-01-01

    Surface plasmon polaritons (SPPs) with the features of subwavelength confinement and strong enhancements have sparked enormous interest. However, in the terahertz regime, due to the perfect conductivities of most metals, it is hard to realize the strong confinement of SPPs, even though the propagation loss could be sufficiently low. One main approach to circumvent this problem is to exploit spoof SPPs, which are expected to exhibit useful subwavelength confinement and relative low propagation loss at terahertz frequencies. Here we report the design, fabrication, and characterization of terahertz spoof SPP waveguides based on corrugated metal surfaces. The various waveguide components, including a straight waveguide, an S-bend waveguide, a Y-splitter, and a directional coupler, were experimentally demonstrated using scanning near-field terahertz microscopy. The proposed waveguide indeed enables propagation, bending, splitting, and coupling of terahertz SPPs and thus paves a new way for the development of flexible and compact plasmonic circuits operating at terahertz frequencies. (C) 2017 Chinese Laser Press

  1. Terahertz spoof surface-plasmon-polariton subwavelength waveguide

    KAUST Repository

    Zhang, Ying

    2017-12-11

    Surface plasmon polaritons (SPPs) with the features of subwavelength confinement and strong enhancements have sparked enormous interest. However, in the terahertz regime, due to the perfect conductivities of most metals, it is hard to realize the strong confinement of SPPs, even though the propagation loss could be sufficiently low. One main approach to circumvent this problem is to exploit spoof SPPs, which are expected to exhibit useful subwavelength confinement and relative low propagation loss at terahertz frequencies. Here we report the design, fabrication, and characterization of terahertz spoof SPP waveguides based on corrugated metal surfaces. The various waveguide components, including a straight waveguide, an S-bend waveguide, a Y-splitter, and a directional coupler, were experimentally demonstrated using scanning near-field terahertz microscopy. The proposed waveguide indeed enables propagation, bending, splitting, and coupling of terahertz SPPs and thus paves a new way for the development of flexible and compact plasmonic circuits operating at terahertz frequencies. (C) 2017 Chinese Laser Press

  2. Topological acoustic polaritons: robust sound manipulation at the subwavelength scale

    Science.gov (United States)

    Yves, Simon; Fleury, Romain; Lemoult, Fabrice; Fink, Mathias; Lerosey, Geoffroy

    2017-07-01

    Topological insulators, a hallmark of condensed matter physics, have recently reached the classical realm of acoustic waves. A remarkable property of time-reversal invariant topological insulators is the presence of unidirectional spin-polarized propagation along their edges, a property that could lead to a wealth of new opportunities in the ability to guide and manipulate sound. Here, we demonstrate and study the possibility to induce topologically non-trivial acoustic states at the deep subwavelength scale, in a structured two-dimensional metamaterial composed of Helmholtz resonators. Radically different from previous designs based on non-resonant sonic crystals, our proposal enables robust sound manipulation on a surface along predefined, subwavelength pathways of arbitrary shapes.

  3. [INVITED] Coherent perfect absorption of electromagnetic wave in subwavelength structures

    Science.gov (United States)

    Yan, Chao; Pu, Mingbo; Luo, Jun; Huang, Yijia; Li, Xiong; Ma, Xiaoliang; Luo, Xiangang

    2018-05-01

    Electromagnetic (EM) absorption is a common process by which the EM energy is transformed into other kinds of energy in the absorber, for example heat. Perfect absorption of EM with structures at subwavelength scale is important for many practical applications, such as stealth technology, thermal control and sensing. Coherent perfect absorption arises from the interplay of interference and absorption, which can be interpreted as a time-reversed process of lasing or EM emitting. It provides a promising way for complete absorption in both nanophotonics and electromagnetics. In this review, we discuss basic principles and properties of a coherent perfect absorber (CPA). Various subwavelength structures including thin films, metamaterials and waveguide-based structures to realize CPAs are compared. We also discuss the potential applications of CPAs.

  4. Topological acoustic polaritons: robust sound manipulation at the subwavelength scale

    International Nuclear Information System (INIS)

    Yves, Simon; Fleury, Romain; Lemoult, Fabrice; Fink, Mathias; Lerosey, Geoffroy

    2017-01-01

    Topological insulators, a hallmark of condensed matter physics, have recently reached the classical realm of acoustic waves. A remarkable property of time-reversal invariant topological insulators is the presence of unidirectional spin-polarized propagation along their edges, a property that could lead to a wealth of new opportunities in the ability to guide and manipulate sound. Here, we demonstrate and study the possibility to induce topologically non-trivial acoustic states at the deep subwavelength scale, in a structured two-dimensional metamaterial composed of Helmholtz resonators. Radically different from previous designs based on non-resonant sonic crystals, our proposal enables robust sound manipulation on a surface along predefined, subwavelength pathways of arbitrary shapes. (paper)

  5. Resonant Excitation of Terahertz Surface Plasmons in Subwavelength Metal Holes

    Directory of Open Access Journals (Sweden)

    Weili Zhang

    2007-01-01

    Full Text Available We present a review of experimental studies of resonant excitation of terahertz surface plasmons in two-dimensional arrays of subwavelength metal holes. Resonant transmission efficiency higher than unity was recently achieved when normalized to the area occupied by the holes. The effects of hole shape, hole dimensions, dielectric function of metals, polarization dependence, and array film thickness on resonant terahertz transmission in metal arrays were investigated by the state-of-the-art terahertz time-domain spectroscopy. In particular, extraordinary terahertz transmission was demonstrated in arrays of subwavelength holes made even from Pb, a generally poor metal, and having thickness of only one-third of skin depth. Terahertz surface plasmons have potential applications in terahertz imaging, biosensing, interconnects, and development of integrated plasmonic components for terahertz generation and detection.

  6. Beyond dipolar regime in high-order plasmon mode bowtie antennas

    Science.gov (United States)

    Cuche, Aurélien; Viarbitskaya, Sviatlana; Kumar, Upkar; Sharma, Jadab; Arbouet, Arnaud; Girard, Christian; Dujardin, Erik

    2017-03-01

    Optical nanoantennas have shown their great potential for far-field to near-field coupling and for light confinement in subwavelength volumes. Here, we report on a multimodal configuration for bright and polarization-dependent bowtie antenna based on large and highly crystalline gold prisms. Each individual prism constituting an antenna arm sustains high order plasmon modes in the visible and near infrared range that allow for high field confinement and two-dimensional optical information propagation. We demonstrate by scanning two-photon luminescence (TPL) microscopy and numerical simulations based on the Green dyadic method that these bowtie antennas result in intense hot spots in different antenna locations as a function of the incident polarization. Finally, we quantify the local field enhancement above the antennas by computing the normalized total decay rate of a molecular system placed in the near field of the antenna gap as a function of the dipole orientation. We demonstrate the existence of a subtle relation between antenna geometry, polarization dependence and field enhancement. These new multimodal optical antennas are excellent far field to near field converter and they open the door for new strategies in the design of coplanar optical components for a wide range of applications including sensing, energy conversion or integrated information processing.

  7. The sub-wavelength imaging performance of disordered wire media

    International Nuclear Information System (INIS)

    Powell, David A.

    2008-01-01

    An analysis of the sub-wavelength imaging performance of disordered thin wire media is undertaken, in order to understand how its performance may be affected by manufacturing errors. The structure is found to be extremely robust to disorder which keeps the wires parallel. Variation in the orientation of the wires and their longitudinal position causes more significant degradation in the image quality, which is quantified numerically

  8. Enhanced terahertz magnetic dipole response by subwavelength fiber

    Directory of Open Access Journals (Sweden)

    Shaghik Atakaramians

    2018-05-01

    Full Text Available Dielectric sub-wavelength particles have opened up a new platform for realization of magnetic light. Recently, we have demonstrated that a dipole emitter by a sub-wavelength fiber leads to an enhanced magnetic response. Here, we experimentally demonstrate an enhanced magnetic dipole source in the terahertz frequency range. By placing the fiber next to the hole in a metal screen, we find that the radiation power can be enhanced more than one order of magnitude. The enhancement is due to the excitation of the Mie-type resonances in the fiber. We demonstrate that such a system is equivalent to a double-fiber system excited by a magnetic source. This coupled magnetic dipole and optical fiber system can be considered a unit cell of metasurfaces for manipulation of terahertz radiation and is a proof-of-concept of a possibility to achieve enhanced radiation of a dipole source in proximity of a sub-wavelength fiber. It can also be scaled down to optical frequencies opening up promising avenues for developing integrated nanophotonic devices such as nanoantennas or lasers on fibers.

  9. Focusing of Acoustic Waves through Acoustic Materials with Subwavelength Structures

    KAUST Repository

    Xiao, Bingmu

    2013-05-01

    In this thesis, wave propagation through acoustic materials with subwavelength slits structures is studied. Guided by the findings, acoustic wave focusing is achieved with a specific material design. By using a parameter retrieving method, an effective medium theory for a slab with periodic subwavelength cut-through slits is successfully derived. The theory is based on eigenfunction solutions to the acoustic wave equation. Numerical simulations are implemented by the finite-difference time-domain (FDTD) method for the two-dimensional acoustic wave equation. The theory provides the effective impedance and refractive index functions for the equivalent medium, which can reproduce the transmission and reflection spectral responses of the original structure. I analytically and numerically investigate both the validity and limitations of the theory, and the influences of material and geometry on the effective spectral responses are studied. Results show that large contrasts in impedance and density are conditions that validate the effective medium theory, and this approximation displays a better accuracy for a thick slab with narrow slits in it. Based on the effective medium theory developed, a design of a at slab with a snake shaped" subwavelength structure is proposed as a means of achieving acoustic focusing. The property of focusing is demonstrated by FDTD simulations. Good agreement is observed between the proposed structure and the equivalent lens pre- dicted by the theory, which leads to robust broadband focusing by a thin at slab.

  10. Tuning subwavelength-structured focus in the hyperbolic metamaterials

    Science.gov (United States)

    Pan, Rong; Tang, Zhixiang; Pan, Jin; Peng, Runwu

    2016-10-01

    In this paper, we have systematically investigated light propagating in the hyperbolic metamaterials (HMMs) covered by a subwavelength grating. Based on the equal-frequency contour analyses, light in the HMM is predicted to propagate along a defined direction because of its hyperbolic dispersion, which is similar to the self-collimating effects in photonic crystals. By using the finite-difference time-domain, numerical simulations demonstrate a subwavelength bright spot at the intersection of the adjacent directional beams. Different from the images in homogeneous media, the magnetic fields and electric fields at the spot are layered, especially for the electric fields Ez that is polarized to the propagating direction, i.e., the layer normal direction. Moreover, the Ez is hollow in the layer plane and is stronger than the other electric field component Ex. Therefore, the whole electric field is structured and its pattern can be tuned by the HMM's effective anisotropic electromagnetic parameters. Our results may be useful for generating subwavelength structured light.

  11. A Single Atom Antenna

    International Nuclear Information System (INIS)

    Trinter, Florian; Williams, Joshua B; Weller, Miriam; Waitz, Markus; Pitzer, Martin; Voigtsberger, Jörg; Schober, Carl; Kastirke, Gregor; Müller, Christian; Goihl, Christoph; Burzynski, Phillip; Wiegandt, Florian; Wallauer, Robert; Kalinin, Anton; Schmidt, Lothar Ph H; Schöffler, Markus S; Jahnke, Till; Dörner, Reinhard; Chiang, Ying-Chih; Gokhberg, Kirill

    2015-01-01

    Here we demonstrate the smallest possible implementation of an antenna-receiver complex which consists of a single (helium) atom acting as the antenna and a second (neon) atom acting as a receiver. (paper)

  12. Antenna Pattern Range (APR)

    Data.gov (United States)

    Federal Laboratory Consortium — TheAntenna Pattern Range (APR)features a non-metallic arch with a trolley to move the transmit antenna from the horizon to zenith. At the center of the ground plane,...

  13. Equipment: Antenna systems

    Science.gov (United States)

    Petrie, L. E.

    1986-03-01

    Some antenna fundamentals as well as definitions of the principal terms used in antenna engineering are described. Methods are presented for determining the desired antenna radiation patterns for HF communication circuit or service area. Sources for obtaining or computing radiation pattern information are outlined. Comparisons are presented between the measured and computed radiation patterns. The effect of the properties of the ground on the antenna gain and the pattern are illustrated for several types of antennas. Numerous examples are given of the radiation patterns for typical antennas used on short, intermediate and long distance circuits for both mobile and fixed service operations. The application of adaptive antenna arrays and active antennas in modern HF communication systems are briefly reviewed.

  14. Antenna theory: Analysis and design

    Science.gov (United States)

    Balanis, C. A.

    The book's main objective is to introduce the fundamental principles of antenna theory and to apply them to the analysis, design, and measurements of antennas. In a description of antennas, the radiation mechanism is discussed along with the current distribution on a thin wire. Fundamental parameters of antennas are examined, taking into account the radiation pattern, radiation power density, radiation intensity, directivity, numerical techniques, gain, antenna efficiency, half-power beamwidth, beam efficiency, bandwidth, polarization, input impedance, and antenna temperature. Attention is given to radiation integrals and auxiliary potential functions, linear wire antennas, loop antennas, linear and circular arrays, self- and mutual impedances of linear elements and arrays, broadband dipoles and matching techniques, traveling wave and broadband antennas, frequency independent antennas and antenna miniaturization, the geometrical theory of diffraction, horns, reflectors and lens antennas, antenna synthesis and continuous sources, and antenna measurements.

  15. Antenna Controller Replacement Software

    Science.gov (United States)

    Chao, Roger Y.; Morgan, Scott C.; Strain, Martha M.; Rockwell, Stephen T.; Shimizu, Kenneth J.; Tehrani, Barzia J.; Kwok, Jaclyn H.; Tuazon-Wong, Michelle; Valtier, Henry; Nalbandi, Reza; hide

    2010-01-01

    The Antenna Controller Replacement (ACR) software accurately points and monitors the Deep Space Network (DSN) 70-m and 34-m high-efficiency (HEF) ground-based antennas that are used to track primarily spacecraft and, periodically, celestial targets. To track a spacecraft, or other targets, the antenna must be accurately pointed at the spacecraft, which can be very far away with very weak signals. ACR s conical scanning capability collects the signal in a circular pattern around the target, calculates the location of the strongest signal, and adjusts the antenna pointing to point directly at the spacecraft. A real-time, closed-loop servo control algorithm performed every 0.02 second allows accurate positioning of the antenna in order to track these distant spacecraft. Additionally, this advanced servo control algorithm provides better antenna pointing performance in windy conditions. The ACR software provides high-level commands that provide a very easy user interface for the DSN operator. The operator only needs to enter two commands to start the antenna and subreflector, and Master Equatorial tracking. The most accurate antenna pointing is accomplished by aligning the antenna to the Master Equatorial, which because of its small size and sheltered location, has the most stable pointing. The antenna has hundreds of digital and analog monitor points. The ACR software provides compact displays to summarize the status of the antenna, subreflector, and the Master Equatorial. The ACR software has two major functions. First, it performs all of the steps required to accurately point the antenna (and subreflector and Master Equatorial) at the spacecraft (or celestial target). This involves controlling the antenna/ subreflector/Master-Equatorial hardware, initiating and monitoring the correct sequence of operations, calculating the position of the spacecraft relative to the antenna, executing the real-time servo control algorithm to maintain the correct position, and

  16. Optical wireless link between a nanoscale antenna and a transducing rectenna.

    Science.gov (United States)

    Dasgupta, Arindam; Mennemanteuil, Marie-Maxime; Buret, Mickaël; Cazier, Nicolas; Colas-des-Francs, Gérard; Bouhelier, Alexandre

    2018-05-18

    Initiated as a cable-replacement solution, short-range wireless power transfer has rapidly become ubiquitous in the development of modern high-data throughput networking in centimeter to meter accessibility range. Wireless technology is now penetrating a higher level of system integration for chip-to-chip and on-chip radiofrequency interconnects. However, standard CMOS integrated millimeter-wave antennas have typical size commensurable with the operating wavelength, and are thus an unrealistic solution for downsizing transmitters and receivers to the micrometer and nanometer scale. Herein, we demonstrate a light-in and electrical signal-out, on-chip wireless near-infrared link between a 220 nm optical antenna and a sub-nanometer rectifying antenna converting the transmitted optical energy into direct electrical current. The co-integration of subwavelength optical functional devices with electronic transduction offers a disruptive solution to interface photons and electrons at the nanoscale for on-chip wireless optical interconnects.

  17. Resonating Terahertz Response of Periodic Arrays of Subwavelength Apertures

    KAUST Repository

    D’ Apuzzo, Fausto; Candeloro, Patrizio; Domenici, Fabio; Autore, M.; Di Pietro, Paola; Perucchi, Andrea; Roy, P.; Sennato, Simona; Bordi, Federico; Di Fabrizio, Enzo M.; Lupi, Stefano

    2014-01-01

    Extraordinary optical transmission (EOT) peaks mediated by plasmonic excitations can be observed in a variety of subwavelength patterned metallic surfaces. In this paper, we have fabricated and spectroscopically characterized plasmon devices exhibiting EOT peaks at terahertz (THz) frequencies. These devices, which resonate with intermediate and collective modes of macromolecules, can be used for detection of materials of biological interest and their performances have been experimentally determined by measuring the variation of the EOT frequencies for thin sub-micrometric organic layers deposited onto the device surface.

  18. Subwavelength position measurements with running-wave driving fields

    Energy Technology Data Exchange (ETDEWEB)

    Evers, Joerg [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Qamar, Sajid [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2011-08-15

    Subwavelength position measurement of quantum particles is discussed. Our setup is based on a closed-loop driving-field configuration, which enforces a sensitivity of the particle dynamics to the phases of the applied fields. Thus, running wave fields are sufficient, avoiding limitations associated with standing-wave-based localization schemes. Reversing the directions of the driving laser fields switches between different magnification levels for the position determination. This allows us to optimize the localization, and at the same time eliminates the need for additional classical measurements common to all previous localization schemes based on spatial periodicity.

  19. Resonating Terahertz Response of Periodic Arrays of Subwavelength Apertures

    KAUST Repository

    D’Apuzzo, Fausto

    2014-10-11

    Extraordinary optical transmission (EOT) peaks mediated by plasmonic excitations can be observed in a variety of subwavelength patterned metallic surfaces. In this paper, we have fabricated and spectroscopically characterized plasmon devices exhibiting EOT peaks at terahertz (THz) frequencies. These devices, which resonate with intermediate and collective modes of macromolecules, can be used for detection of materials of biological interest and their performances have been experimentally determined by measuring the variation of the EOT frequencies for thin sub-micrometric organic layers deposited onto the device surface.

  20. Spectral light separator based on deep-subwavelength resonant apertures in a metallic film

    Energy Technology Data Exchange (ETDEWEB)

    Büyükalp, Yasin; Catrysse, Peter B., E-mail: pcatryss@stanford.edu; Shin, Wonseok; Fan, Shanhui, E-mail: shanhui@stanford.edu [E. L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-07-07

    We propose to funnel, select, and collect light spectrally by exploiting the unique properties of deep-subwavelength resonant apertures in a metallic film. In our approach, each aperture has an electromagnetic cross section that is much larger than its physical size while the frequency of the collected light is controlled by its height through the Fabry-Pérot resonance mechanism. The electromagnetic crosstalk between apertures remains low despite physical separations in the deep-subwavelength range. The resulting device enables an extremely efficient, subwavelength way to decompose light into its spectral components without the loss of photons and spatial coregistration errors. As a specific example, we show a subwavelength-size structure with three deep-subwavelength slits in a metallic film designed to operate in the mid-wave infrared range between 3 and 5.5 μm.

  1. Phased array antenna control

    Science.gov (United States)

    Doland, G. D. (Inventor)

    1978-01-01

    Several new and useful improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements are provided. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas.

  2. Experiments with dipole antennas

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2009-01-01

    Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a variant of the Yagi-Uda antenna is explored. The experiments are suitable as laboratory works and classroom demonstrations, and are attractive for student projects.

  3. Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Abul K [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Han, Jiaguang [OSU; Lu, Xinchao [OSU; Zhang, Weili [OSU

    2009-01-01

    The fascinating properties of plasmonic structures have had significant impact on the development of next generation ultracompact photonic and optoelectronic components. We study two-dimensional plasmonic structures functioning at terahertz frequencies. Resonant terahertz response due to surface plasmons and dipole localized surface plasmons were investigated by the state-of-the-art terahertz time domain spectroscopy (THz-TDS) using both transmission and reflection configurations. Extraordinary terahertz transmission was demonstrated through the subwavelength metallic hole arrays made from good conducting metals as well as poor metals. Metallic arrays m!lde from Pb, generally a poor metal, and having optically thin thicknesses less than one-third of a skin depth also contributed in enhanced THz transmission. A direct transition of a surface plasmon resonance from a photonic crystal minimum was observed in a photo-doped semiconductor array. Electrical controls of the surface plasmon resonances by hybridization of the Schottkey diode between the metallic grating and the semiconductor substrate are investigated as a function of the applied reverse bias. In addition, we have demonstrated photo-induced creation and annihilation of surface plasmons with appropriate semiconductors at room temperature. According to the Fano model, the transmission properties are characterized by two essential contributions: resonant excitation of surface plasmons and nonresonant direct transmission. Such plasmonic structures may find fascinating applications in terahertz imaging, biomedical sensing, subwavelength terahertz spectroscopy, tunable filters, and integrated terahertz devices.

  4. A super-oscillatory lens optical microscope for subwavelength imaging.

    Science.gov (United States)

    Rogers, Edward T F; Lindberg, Jari; Roy, Tapashree; Savo, Salvatore; Chad, John E; Dennis, Mark R; Zheludev, Nikolay I

    2012-03-25

    The past decade has seen an intensive effort to achieve optical imaging resolution beyond the diffraction limit. Apart from the Pendry-Veselago negative index superlens, implementation of which in optics faces challenges of losses and as yet unattainable fabrication finesse, other super-resolution approaches necessitate the lens either to be in the near proximity of the object or manufactured on it, or work only for a narrow class of samples, such as intensely luminescent or sparse objects. Here we report a new super-resolution microscope for optical imaging that beats the diffraction limit of conventional instruments and the recently demonstrated near-field optical superlens and hyperlens. This non-invasive subwavelength imaging paradigm uses a binary amplitude mask for direct focusing of laser light into a subwavelength spot in the post-evanescent field by precisely tailoring the interference of a large number of beams diffracted from a nanostructured mask. The new technology, which--in principle--has no physical limits on resolution, could be universally used for imaging at any wavelength and does not depend on the luminescence of the object, which can be tens of micrometres away from the mask. It has been implemented as a straightforward modification of a conventional microscope showing resolution better than λ/6.

  5. Fabrication of sub-wavelength photonic structures by nanoimprint lithography

    Energy Technology Data Exchange (ETDEWEB)

    Kontio, J.

    2013-11-01

    Nanoimprint lithography (NIL) is a novel but already a mature lithography technique. In this thesis it is applied to the fabrication of nanophotonic devices using its main advantage: the fast production of sub-micron features in high volume in a cost-effective way. In this thesis, fabrication methods for conical metal structures for plasmonic applications and sub-wavelength grating based broad-band mirrors are presented. Conical metal structures, nanocones, with plasmonic properties are interesting because they enable concentrating the energy of light in very tight spots resulting in very high local intensities of electromagnetic energy. The nanocone formation process is studied with several metals. Enhanced second harmonic generation using gold nanocones is presented. Bridged-nanocones are used to enhance Raman scattering from a dye solution. The sub-wavelength grating mirror is an interesting structure for photonics because it is very simple to fabricate and its reflectivity can be extended to the far infrared wavelength range. It also has polarization dependent properties which are used in this thesis to stabilize the output beam of infrared semiconductor disk laser. NIL is shown to be useful a technique in the fabrication of nanophotonic devices in the novel and rapidly growing field of plasmonics and also in more traditional, but still developing, semiconductor laser applications (orig.)

  6. Cellular Reflectarray Antenna

    Science.gov (United States)

    Romanofsky, Robert R.

    2010-01-01

    The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

  7. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  8. Directional borehole antenna - Theory

    International Nuclear Information System (INIS)

    Falk, L.

    1992-02-01

    A directional antenna has been developed for the borehole radar constructed during phase 2 of the Stripa project. The new antenna can determine the azimuth of a strong reflector with an accuracy of about 3 degrees as confirmed during experiments in Stripa, although the ratio of borehole diameter to wavelength is small, about 0.03. The antenna synthesizes the effect of a loop antenna rotating in the borehole from four signals measured in turn by a stationary antenna. These signals are also used to calculate an electric dipole signal and a check sum which is used to examine the function of the system. The theory of directional antennas is reviewed and used to design an antenna consisting of four parallel wires. The radiation pattern of this antenna is calculated using transmission line theory with due regard to polarization, which is of fundamental importance for the analysis of directional data. In particular the multipole expansion of the field is calculated to describe the antenna radiation pattern. Various sources of error, e.g. the effect of the borehole, are discussed and the methods of calibrating the antenna are reviewed. The ambiguity inherent in a loop antenna can be removed by taking the phase of the signal into account. Typical reflectors in rock, e.g. fracture zones an tunnels, may be modelled as simple geometrical structures. The corresponding analysis is described and exemplified on measurements from Stripa. Radar data is nowadays usually analyzed directly on the computer screen using the program RADINTER developed within the Stripa project. An algorithm for automatic estimation of the parameters of a reflector have been tested with some success. The relation between measured radar data and external coordinates as determined by rotational indicators is finally expressed in terms of Euler angles. (au)

  9. Polarization Multiplexing of Fluorescent Emission Using Multiresonant Plasmonic Antennas.

    Science.gov (United States)

    De Leo, Eva; Cocina, Ario; Tiwari, Preksha; Poulikakos, Lisa V; Marqués-Gallego, Patricia; le Feber, Boris; Norris, David J; Prins, Ferry

    2017-12-26

    Combining the ability to localize electromagnetic fields at the nanoscale with a directional response, plasmonic antennas offer an effective strategy to shape the far-field pattern of coupled emitters. Here, we introduce a family of directional multiresonant antennas that allows for polarization-resolved spectral identification of fluorescent emission. The geometry consists of a central aperture surrounded by concentric polygonal corrugations. By varying the periodicity of each axis of the polygon individually, this structure can support multiple resonances that provide independent control over emission directionality for multiple wavelengths. Moreover, since each resonant wavelength is directly mapped to a specific polarization orientation, spectral information can be encoded in the polarization state of the out-scattered beam. To demonstrate the potential of such structures in enabling simplified detection schemes and additional functionalities in sensing and imaging applications, we use the central subwavelength aperture as a built-in nanocuvette and manipulate the fluorescent response of colloidal-quantum-dot emitters coupled to the multiresonant antenna.

  10. Enhanced transmission of transverse electric waves through periodic arrays of structured subwavelength apertures

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Peng, Liang; Mortensen, Asger

    2010-01-01

    Transmission through sub-wavelength apertures in perfect metals is expected to be strongly suppressed. However, by structural engineering of the apertures, we numerically demonstrate that the transmission of transverse electric waves through periodic arrays of subwavelength apertures in a thin...... metallic film can be significantly enhanced. Based on equivalent circuit theory analysis, periodic arrays of square structured subwavelength apertures are obtained with a 1900-fold transmission enhancement factor when the side length a of the apertures is 10 times smaller than the wavelength (a/λ =0...

  11. Terahertz near-field imaging using subwavelength plasmonic apertures and a quantum cascade laser source.

    Science.gov (United States)

    Baragwanath, Adam J; Freeman, Joshua R; Gallant, Andrew J; Zeitler, J Axel; Beere, Harvey E; Ritchie, David A; Chamberlain, J Martyn

    2011-07-01

    The first demonstration, to our knowledge, of near-field imaging using subwavelength plasmonic apertures with a terahertz quantum cascade laser source is presented. "Bull's-eye" apertures, featuring subwavelength circular apertures flanked by periodic annular corrugations were created using a novel fabrication method. A fivefold increase in intensity was observed for plasmonic apertures over plain apertures of the same diameter. Detailed studies of the transmitted beam profiles were undertaken for apertures with both planarized and corrugated exit facets, with the former producing spatially uniform intensity profiles and subwavelength spatial resolution. Finally, a proof-of-concept imaging experiment is presented, where an inhomogeneous pharmaceutical drug coating is investigated.

  12. Single photon transport by a moving atom through sub-wavelength hole

    International Nuclear Information System (INIS)

    Afanasiev, A.E.; Melentiev, P.N.; Kuzin, A.A.; Kalatskiy, A.Yu.; Balykin, V.I.

    2017-01-01

    The results of investigation of photon transport through the subwavelength hole in the opaque screen by using single neutral atom are represented. The basis of the proposed and implemented method is the absorption of a photon by a neutral atom immediately before the subwavelength aperture, traveling of the atoms through the hole and emission of a photon on the other side of the screen. Realized method is the alternative approach to existing for photon transport through a subwavelength aperture: 1) self-sustained transmittance of a photon through the aperture according to the Bethe’s model; 2) extra ordinary transmission because of surface-plasmon excitation.

  13. Handbook of antenna technologies

    CERN Document Server

    Liu, Duixian; Nakano, Hisamatsu; Qing, Xianming; Zwick, Thomas

    2016-01-01

    The Handbook of Antenna Technologies aims to present the rapid development of antenna technologies, particularly in the past two decades, and also showcasing the newly developed technologies and the latest applications. The handbook will provide readers with the comprehensive updated reference information covering theory, modeling and optimization methods, design and measurement, new electromagnetic materials, and applications of antennas. The handbook will widely cover not only all key antenna design issues but also fundamentals, issues related to antennas (transmission, propagation, feeding structure, materials, fabrication, measurement, system, and unique design challenges in specific applications). This handbook will benefit the readers as a full and quick technical reference with a high-level historic review of technology, detailed technical descriptions and the latest practical applications.

  14. GPS antenna designs

    Science.gov (United States)

    Laube, Samuel J. P.

    1987-05-01

    Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

  15. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.; Panaro, S.; Zaccaria, R. Proietti; Raja, W.; Liberale, Carlo; Dipalo, M.; Messina, G. C.; Wang, H.; De Angelis, F.; Toma, A.

    2015-01-01

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  16. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.

    2015-06-09

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  17. Longitudinal Lorentz force on a subwavelength-diameter optical fiber

    International Nuclear Information System (INIS)

    Yu Huakang; Fang Wei; Gu Fuxing; Yang Zongyin; Tong Limin; Qiu Min

    2011-01-01

    We analyze the longitudinal Lorentz forces that a propagating continuous-wave light exerts on a subwavelength-diameter optical fiber. Our theoretical results show that, during the propagating process, the guided light exerts no net time-averaged force on the fiber. Via numerical simulation, we find a significant overall pull force of 0.4 pN/mW acting on a 450-nm-diam fiber tip at a wavelength of 980 nm due to the scattering of the end face and a calculated force distribution reveals the feature of a near-field accumulation. Our results may be helpful to the configuration of optomechanical components or devices based on these fibers.

  18. Bio-functional subwavelength optical waveguides for biodetection

    Energy Technology Data Exchange (ETDEWEB)

    Sirbuly, D J; Fischer, N; Huang, S; Artyukhin, A

    2007-07-10

    We report a versatile biofunctional subwavelength photonic device platform for real-time detection of biological molecules. Our devices contain lipid bilayer membranes fused onto metal oxide nanowire waveguides stretched across polymeric flow channels. The lipid bilayers incorporating target receptors are submersed in the propagating evanescent field of the optical cavity. We show that the lipid bilayers in our devices are continuous, have very high mobile fraction, and are resistant to fouling. We also demonstrate that our platform allows rapid membrane exchange. Finally we use this device for detection of specific DNA sequences in solution by anchoring complementary DNA target strands in the lipid bilayer. This evanescent wave sensing architecture holds great potential for portable, all-optical detection systems.

  19. Subwavelength Plasmonic Color Printing Protected for Ambient Use

    DEFF Research Database (Denmark)

    Roberts, Alexander Sylvester; Pors, Anders Lambertus; Albrektsen, Ole

    2014-01-01

    We demonstrate plasmonic color printing with subwavelength resolution using circular gap-plasmon resonators (GPRs) arranged in 340 nm period arrays of square unit cells and fabricated with single-step electron-beam lithography. We develop a printing procedure resulting in correct single-pixel color...... reproduction, high color uniformity of colored areas, and high reproduction fidelity. Furthermore, we demonstrate that, due to inherent stability of GPRs with respect to surfactants, the fabricated color print can be protected with a transparent dielectric overlay for ambient use without destroying its...... coloring. Using finite-element simulations, we uncover the physical mechanisms responsible for color printing with GPR arrays and suggest the appropriate design procedure minimizing the influence of the protection layer....

  20. Hybrid Surface Plasmon Polariton Modes of Subwavelength Nanowire Resonators

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Willatzen, Morten

    2015-01-01

    -localized gap plasmon mode are studied depending on the vacuum wavelength. In order to directly compare resonators, where metal and semiconductor nanowires are employed, we consider the two resonators, both including silver slab and magnesium fluoride gap region, as is shown in figure. The two compared......We perform Comsol simulations of two types of hybrid plasmonic resonator configurations, similar to those proposed for nanowire plasmonic laser in [1] and [2]. In both references the nanowire - based plasmonic resonators are studied, which overall sizes are larger than the wavelength in vacuum....... However, it is advantageous for the nanolaser to have subwavelength sizes at least in two dimensions. Therefore, we study the two configurations and the hybrid mode behavior in the case, where resonator sizes are smaller than the half of the wavelength in vacuum. First, we assume finite dimensions...

  1. Subwavelength Localization of Atomic Excitation Using Electromagnetically Induced Transparency

    Directory of Open Access Journals (Sweden)

    J. A. Miles

    2013-09-01

    Full Text Available We report an experiment in which an atomic excitation is localized to a spatial width that is a factor of 8 smaller than the wavelength of the incident light. The experiment utilizes the sensitivity of the dark state of electromagnetically induced transparency (EIT to the intensity of the coupling laser beam. A standing-wave coupling laser with a sinusoidally varying intensity yields tightly confined Raman excitations during the EIT process. The excitations, located near the nodes of the intensity profile, have a width of 100 nm. The experiment is performed using ultracold ^{87}Rb atoms trapped in an optical dipole trap, and atomic localization is achieved with EIT pulses that are approximately 100 ns long. To probe subwavelength atom localization, we have developed a technique that can measure the width of the atomic excitations with nanometer spatial resolution.

  2. Coherent patterning of matter waves with subwavelength localization

    International Nuclear Information System (INIS)

    Mompart, J.; Ahufinger, V.; Birkl, G.

    2009-01-01

    We propose the subwavelength localization via adiabatic passage (SLAP) technique to coherently achieve state-selective patterning of matter waves well beyond the diffraction limit. The SLAP technique consists in coupling two partially overlapping and spatially structured laser fields to three internal levels of the matter wave yielding state-selective localization at those positions where the adiabatic passage process does not occur. We show that by means of this technique matter wave localization down to the single nanometer scale can be achieved. We analyze in detail the potential implementation of the SLAP technique for nanolithography with an atomic beam of metastable Ne* and for coherent patterning of a two-component 87 Rb Bose-Einstein condensate.

  3. All-optical switching of the transmission of electromagnetic radiation through subwavelength apertures

    NARCIS (Netherlands)

    Janke, C.; Gómez Rivas, J.; Haring Bolivar, P.; Kurz, H.

    2005-01-01

    Unprecedented optical control of the surface plasmon polariton assisted transmission of terahertz radiation through subwavelength apertures is rendered possible by carrier-induced changes to the dielectric properties of a semiconductor grating. Although the study presented is static, the extension

  4. Shaping of few-cycle laser pulses via a subwavelength structure

    International Nuclear Information System (INIS)

    Guo Liang; Xie Xiao-Tao; Zhan Zhi-Ming

    2013-01-01

    We theoretically investigate the propagation of few-cycle laser pulses in resonant two-level dense media with a subwavelength structure, which is described by the full Maxwell—Bloch equations without the frame of slowly varying envelope and rotating wave approximations. The input pulses can be shaped into shorter ones with a single or less than one optical cycle. The effect of the parameters of the subwavelength structure and laser pulses is studied. Our study shows that the media with a subwavelength structure can significantly shape the few-cycle pulses into a subcycle pulse, even for the case of chirp pulses as input fields. This suggests that such subwavelength structures have potential application in the shaping of few-cycle laser pulses. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Smart antennas in aerospace applications

    NARCIS (Netherlands)

    Verpoorte, Jaco; Schippers, Harmen; Roeloffzen, C.G.H.; Marpaung, D.A.I.

    2010-01-01

    The interest in Smart Antennas for aerospace applications is growing. This paper describes smart antennas which can be used on aircraft. Two aerospace applications are discussed in more detail: a phased array antenna with optical beam forming and a large vibrating phased array antenna with

  6. Electro-optical study of nanoscale Al-Si-truncated conical photodetector with subwavelength aperture

    Science.gov (United States)

    Karelits, Matityahu; Mandelbaum, Yaakov; Chelly, Avraham; Karsenty, Avi

    2017-10-01

    A type of silicon photodiode has been designed and simulated to probe the optical near field and detect evanescent waves. These waves convey subwavelength resolution. This photodiode consists of a truncated conical shaped, silicon Schottky diode having a subwavelength aperture of 150 nm. Electrical and electro-optical simulations have been conducted. These results are promising toward the fabrication of a new generation of photodetector devices.

  7. Antennas from theory to practice

    CERN Document Server

    Huang, Yi

    2008-01-01

    Practical, concise and complete reference for the basics of modern antenna design Antennas: from Theory to Practice discusses the basics of modern antenna design and theory. Developed specifically for engineers and designers who work with radio communications, radar and RF engineering, this book offers practical and hands-on treatment of antenna theory and techniques, and provides its readers the skills to analyse, design and measure various antennas. Key features: Provides thorough coverage on the basics of transmission lines, radio waves and propag

  8. Buoyant Cable Antenna System

    National Research Council Canada - National Science Library

    Gerhard, Erich M

    2008-01-01

    .... For instance, in one embodiment two oppositely extending curves each float and each are pressed by the water in a balanced manner to provide a stable platform for one or more antennas which can be...

  9. Micropatch Antenna Phase Shifting

    National Research Council Canada - National Science Library

    Thursby, Michael

    2000-01-01

    .... We have been looking at the ability of embedded element to adjust the phase shift seen by the element with the goal of being able to remove the phase shifting devices from the antenna and replace...

  10. Micropatch Antenna Phase Shifting

    National Research Council Canada - National Science Library

    Thursby, Michael

    1999-01-01

    .... We have been looking at the ability of embedded element to adjust the phase shift seen by the element wit the goal of being able to remove the phase shifting devices from the antenna and replace...

  11. Microwave antenna holography

    Science.gov (United States)

    Rochblatt, David J.; Seidel, Boris L.

    1992-01-01

    This microwave holography technique utilizes the Fourier transform relation between the complex far field radiation pattern of an antenna and the complex aperture field distribution. Resulting aperture phase and amplitude distribution data can be used to precisely characterize various crucial performance parameters, including panel alignment, panel shaping, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation effects. The methodology of data processing presented here was successfully applied to the Deep Space Network (DSN) 34-m beam waveguide antennas. The antenna performance was improved at all operating frequencies by reducing the main reflector mechanical surface rms error to 0.43 mm. At Ka-band (32 GHz), the estimated improvement is 4.1 dB, resulting in an aperture efficiency of 52 percent. The performance improvement was verified by efficiency measurements and additional holographic measurements.

  12. Graphene based metamaterials for terahertz cloaking and subwavelength imaging

    Science.gov (United States)

    Forouzmand, Seyedali

    Graphene is a two-dimensional carbon crystal that became one of the most controversial topics of research in the last few years. The intense interest in graphene stems from recent demonstrations of their potentially revolutionary electromagnetic applications -- including negative refraction, subdiffraction imaging, and even invisibility -- which have suggested a wide range of new devices for communications, sensing, and biomedicine. In addition, it has been shown that graphene is amenable to unique patterning schemes such as cutting, bending, folding, and fusion that are predicted to lead to interesting properties. A recent proposed application of graphene is in engineering the scattering properties of objects, which may be leveraged in applications such as radar-cross-section management and stealth, where it may be required to make one object look like another object or render an object completely invisible. We present the analytical formulation for the analysis of electromagnetic interaction with a finite conducting wedge covered with a cylindrically shaped nanostructured graphene metasurface, resulting in the scattering cancellation of the dominant scattering mode for all the incident and all the observation angles. Following this idea, the cylindrical graphene metasurface is utilized for cloaking of several concentric finite conducting wedges. In addition, a wedge shaped metasurface is proposed as an alternative approach for cloaking of finite wedges. The resolution of the conventional imaging lenses is restricted by the natural diffraction limit. Artificially engineered metamaterials now offer the possibility of creating a superlens that overcomes this restriction. We demonstrate that a wire medium (WM) slab loaded with graphene sheets enables the enhancement of the near field for subwavelength imaging at terahertz (THz) frequencies. The analysis is based on the nonlocal homogenization model for WM with the additional boundary condition in the connection of

  13. Purcell effect for active tuning of light scattering from semiconductor optical antennas.

    Science.gov (United States)

    Holsteen, Aaron L; Raza, Søren; Fan, Pengyu; Kik, Pieter G; Brongersma, Mark L

    2017-12-15

    Subwavelength, high-refractive index semiconductor nanostructures support optical resonances that endow them with valuable antenna functions. Control over the intrinsic properties, including their complex refractive index, size, and geometry, has been used to manipulate fundamental light absorption, scattering, and emission processes in nanostructured optoelectronic devices. In this study, we harness the electric and magnetic resonances of such antennas to achieve a very strong dependence of the optical properties on the external environment. Specifically, we illustrate how the resonant scattering wavelength of single silicon nanowires is tunable across the entire visible spectrum by simply moving the height of the nanowires above a metallic mirror. We apply this concept by using a nanoelectromechanical platform to demonstrate active tuning. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  14. Imaging the Hidden Modes of Ultrathin Plasmonic Strip Antennas by Cathodoluminescence

    KAUST Repository

    Barnard, Edward S.

    2011-10-12

    We perform spectrally resolved cathodoluminescence (CL) imaging nanoscopy using a 30 keV electron beam to identify the resonant modes of an ultrathin (20 nm), laterally tapered plasmonic Ag nanostrip antenna. We resolve with deep-subwavelength resolution four antenna resonances (resonance orders m = 2-5) that are ascribed to surface plasmon polariton standing waves that are confined on the strip. We map the local density of states on the strip surface and show that it has contributions from symmetric and antisymmetric surface plasmon polariton modes, each with a very different mode index. This work illustrates the power of CL experiments that can visualize hidden modes that for symmetry reasons have been elusive in optical light scattering experiments. © 2011 American Chemical Society.

  15. Metallic strip gratings in the sub-subwavelength regime.

    Science.gov (United States)

    Savin, Adriana; Steigmann, Rozina; Bruma, Alina

    2014-07-04

    Metallic strip gratings (MSG) have different applications, ranging from printed circuits to filters in microwave domains. When they are under the influence of an electromagnetic field, evanescent and/or abnormal modes appear in the region between the traces, their utilization leading to the development of new electromagnetic nondestructive evaluation methods. This paper studies the behavior of MSGs in the sub-subwavelength regime when they are excited with TE(z) or TM(z) polarized plane waves and the slits are filled with different dielectrics. The appearance of propagating, evanescent and abnormal modes is emphasized using an electromagnetic sensor with metamaterials lens realized with two conical Swiss rolls, which allows the extraction of the information carried by the guided evanescent waves. The evanescent waves, manipulated by the electromagnetic sensor with metamaterial lenses, improve the electromagnetic images so that a better spatial resolution is obtained, exceeding the limit imposed by diffraction. Their theoretical and experimental confirmation opens the perspective for development of new types of sensors working in radio and microwave frequencies.

  16. Metallic Strip Gratings in the Sub-Subwavelength Regime

    Directory of Open Access Journals (Sweden)

    Adriana Savin

    2014-07-01

    Full Text Available Metallic strip gratings (MSG have different applications, ranging from printed circuits to filters in microwave domains. When they are under the influence of an electromagnetic field, evanescent and/or abnormal modes appear in the region between the traces, their utilization leading to the development of new electromagnetic nondestructive evaluation methods. This paper studies the behavior of MSGs in the sub-subwavelength regime when they are excited with TEz or TMz polarized plane waves and the slits are filled with different dielectrics. The appearance of propagating, evanescent and abnormal modes is emphasized using an electromagnetic sensor with metamaterials lens realized with two conical Swiss rolls, which allows the extraction of the information carried by the guided evanescent waves. The evanescent waves, manipulated by the electromagnetic sensor with metamaterial lenses, improve the electromagnetic images so that a better spatial resolution is obtained, exceeding the limit imposed by diffraction. Their theoretical and experimental confirmation opens the perspective for development of new types of sensors working in radio and microwave frequencies.

  17. Sub-wavelength grating mode transformers in silicon slab waveguides.

    Science.gov (United States)

    Bock, Przemek J; Cheben, Pavel; Schmid, Jens H; Delâge, André; Xu, Dan-Xia; Janz, Siegfried; Hall, Trevor J

    2009-10-12

    We report on several new types of sub-wavelength grating (SWG) gradient index structures for efficient mode coupling in high index contrast slab waveguides. Using a SWG, an adiabatic transition is achieved at the interface between silicon-on-insulator waveguides of different geometries. The SWG transition region minimizes both fundamental mode mismatch loss and coupling to higher order modes. By creating the gradient effective index region in the direction of propagation, we demonstrate that efficient vertical mode transformation can be achieved between slab waveguides of different core thickness. The structures which we propose can be fabricated by a single etch step. Using 3D finite-difference time-domain simulations we study the loss, polarization dependence and the higher order mode excitation for two types (triangular and triangular-transverse) of SWG transition regions between silicon-on-insulator slab waveguides of different core thicknesses. We demonstrate two solutions to reduce the polarization dependent loss of these structures. Finally, we propose an implementation of SWG structures to reduce loss and higher order mode excitation between a slab waveguide and a phase array of an array waveguide grating (AWG). Compared to a conventional AWG, the loss is reduced from -1.4 dB to < -0.2 dB at the slab-array interface.

  18. Remote sub-wavelength focusing of ultrasonically activated Lorentz current

    Science.gov (United States)

    Rekhi, Angad S.; Arbabian, Amin

    2017-04-01

    We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.

  19. Modeling of compact loop antennas

    International Nuclear Information System (INIS)

    Baity, F.W.

    1987-01-01

    A general compact loop antenna model which treats all elements of the antenna as lossy transmission lines has been developed. In addition to capacitively-tuned resonant double loop (RDL) antennas the model treats stub-tuned resonant double loop antennas. Calculations using the model have been compared with measurements on full-scale mockups of resonant double loop antennas for ATF and TFTR in order to refine the transmission line parameters. Results from the model are presented for RDL antenna designs for ATF, TFTR, Tore Supra, and for the Compact Ignition Tokamak

  20. Antenna for Ultrawideband Channel Sounding

    DEFF Research Database (Denmark)

    Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Pedersen, Gert F.

    2016-01-01

    A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact on the a......A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact...

  1. Value Engineering and Function Analysis: Frameworks for Innovation in Antenna Systems

    Directory of Open Access Journals (Sweden)

    Hamid Reza Fartookzadeh

    2018-04-01

    Full Text Available Value engineering (VE and function analysis (FA are technological tools for the functional enhancement and cost reduction of engineering projects. They also help to overcome mental inertia by acknowledging the voice of the customer in complicated systems. Antenna engineering, providing electromagnetic remote links, is an important area in engineering science, with a large number of innovative concepts. However, managing innovative ideas to improve performance, reliability, quality, safety, and reduce life cycle costs, is still a work in progress. This research was designed to apply VE and FA as frameworks for innovative ideas in antenna systems, especially with regard to imaging and radar systems. FA diagrams free a designers’ mind from tools to instead focus on purpose, which can help them to obtain better ideas for solutions to problems. It was identified that there were several options available for functionality enhancement and cost reduction. The required functionalities of the components of antenna systems, and their advantages and limitations were indicated. In addition, it was identified that some of the advantages and limitations appeared for combinations of the components. Alternative methods for applications, such as polarization conversion and the separation of outgoing and incoming electromagnetic waves, were studied. Circular polarization (CP is important for two-way communication, since left-handed circularly polarized waves usually return with right-handed CP from targets. Therefore, various methods for producing CP were discussed, such as metamaterial-based linear to circular polarization converters and waveguide polarizers. Also, potential extra applications for these systems were explained. Two examples were: (1 merging multiple systems with different operating frequencies using multiband components; and (2 applying a feeding system for multiple reflectors using surfaces that reflect half of the wave and transmit the other

  2. Fabrication of subwavelength metallic structures by using a metal direct imprinting process

    International Nuclear Information System (INIS)

    Hsieh, C W; Hsiung, H Y; Lu, Y T; Sung, C K; Wang, W H

    2007-01-01

    This work employs a metal direct imprinting process, which possesses the characteristics of simplicity, low-cost and high resolution, for the fabrication of subwavelength structures on a metallic thin film. Herein, the mould featuring periodic line structures is manufactured by using E-beam lithography and followed by a dry etching process; meanwhile, the thin film is fabricated by sputtering Al on a silicon substrate. AFM section analyses are employed to measure imprinting depths of the subwavelength metallic structures and it is found that the uniformity of the imprinting depths is affected by the designed patterns, the material property of thin film and mould deformation. The process temperature and the mould filling that influence the transferred quality are investigated. In addition, TEM is also utilized to examine defects in the subwavelength metallic structures. Finally, good quality subwavelength metallic structures are fabricated under a pressure of 300 MPa for 60 s at room temperature. In this study, we have demonstrated that subwavelength metallic structures with a minimum linewidth of less than 100 nm on the Al thin film are successfully constructed by the metal direct imprinting process

  3. Direct writing of sub-wavelength ripples on silicon using femtosecond laser at high repetition rate

    International Nuclear Information System (INIS)

    Xie, Changxin; Li, Xiaohong; Liu, Kaijun; Zhu, Min; Qiu, Rong; Zhou, Qiang

    2016-01-01

    Graphical abstract: - Highlights: • The NSRs and DSRs are obtained on silicon surface. • With increasing direct writing speed, the NSRs suddenly changes and becomes the DSRs. • We develop a Sipe–Drude interference theory by considering the thermal excitation. - Abstract: The near sub-wavelength and deep sub-wavelength ripples on monocrystalline silicon were formed in air by using linearly polarized and high repetition rate femtosecond laser pulses (f = 76 MHz, λ = 800 nm, τ = 50 fs). The effects of laser pulse energy, direct writing speed and laser polarization on silicon surface morphology are studied. When the laser pulse energy is 2 nJ/pulse and the direct writing speed varies from 10 to 25 mm/s, the near sub-wavelength ripples (NSRs) with orientation perpendicular to the laser polarization are generated. While the direct writing speed reaches 30 mm/s, the direction of the obtained deep sub-wavelength ripples (DSRs) suddenly changes and becomes parallel to the laser polarization, rarely reported so far for femtosecond laser irradiation of silicon. Meanwhile, we extend the Sipe–Drude interference theory by considering the thermal excitation, and numerically calculate the efficacy factor for silicon irradiated by femtosecond laser pulses. The revised Sipe–Drude interference theoretical results show good agreement with the periods and orientations of sub-wavelength ripples.

  4. Stretchable antenna for wearable electronics

    KAUST Repository

    Hussain, Muhammad Mustafa; Hussain, Aftab Mustansir; Shamim, Atif; Ghaffar, Farhan Abdul

    2017-01-01

    Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal

  5. Dynamic Flaps Electronic Scan Antenna

    National Research Council Canada - National Science Library

    Gonzalez, Daniel

    2000-01-01

    A dynamic FLAPS(TM) electronic scan antenna was the focus of this research. The novelty S of this SBIR resides in the use of plasma as the main component of this dynamic X-Band phased S array antenna...

  6. Wireless Distributed Antenna MIMO

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to system applications of multicore optical fibers. One embodiment relates to a base transceiver station for a wireless telecommunication system comprising a plurality of antenna units arranged in a MIMO configuration and adapted for transmission and/or reception...... of radio-frequency signals, an optical transmitter in the form of an electro-optic conversion unit for each of said plurality of antenna units, each electro-optic conversion unit adapted for converting an RF signal into an optical signal, a plurality of a single core optical fibers for guiding the optical...

  7. Printed MIMO antenna engineering

    CERN Document Server

    Sharawi, Mohammad S

    2014-01-01

    Wireless communications has made a huge leap during the past two decades. The multiple-input-multiple-output (MIMO) technology was proposed in the 1990's as a viable solution that can overcome the data rate limit experienced by single-input-single-output (SISO) systems. This resource is focused on printed MIMO antenna system design. Printed antennas are widely used in mobile and handheld terminals due to their conformity with the device, low cost, good integration within the device elements and mechanical parts, as well as ease of fabrication.A perfect design companion for practicing engineers

  8. Non-standard antennas

    CERN Document Server

    Le Chevalier, Francois; Staraj, Robert

    2013-01-01

    This book aims at describing the wide variety of new technologies and concepts of non-standard antenna systems - reconfigurable, integrated, terahertz, deformable, ultra-wideband, using metamaterials, or MEMS,  etc, and how they open the way to a wide range of applications, from personal security and communications to multifunction radars and towed sonars, or satellite navigation systems, with space-time diversity on transmit and receive. A reference book for designers  in this lively scientific community linking antenna experts and signal processing engineers.

  9. DSN Microwave Antenna Holography

    Science.gov (United States)

    Rochblatt, D. J.; Seidel, B. L.

    1984-01-01

    The DSN microwave antenna holography project will obtain three-dimensional pictures of the large DSN antenna surfaces. These pictures must be of suffi icient resolution to allow adjustment of the reflector panels to an rms surface of 0.5 mm (0.25 mm, goal). The major parameters and equations needed to define a holographic measurement system are outlined and then the proof of concept demonstration measurement that was made at DSS-43 (Australia) that resulted in contour maps with spatial resolution of 7 m in the aperture plane and resolution orthogonal to the aperture plane of 0.7 mm was discussed.

  10. Optical response of bowtie antennas

    Science.gov (United States)

    Guo, Ying-Nan; Pan, Shi; Li, Xu-Feng; Wang, Shuo; Wang, Qiao

    2010-10-01

    Optical properties of bowtie antennas are investigated using a numerical method of finite-difference time-domain (FDTD). The optical response in the antenna feed gap is simulated as functions of its geometry parameters (flare angle, arm length, apex width, thickness, gap dimension, as well as the index of substrate), which provide a clear guideline to exploit such antenna structures in practice.

  11. Subwavelength resolution Fourier ptychography with hemispherical digital condensers

    Science.gov (United States)

    Pan, An; Zhang, Yan; Li, Maosen; Zhou, Meiling; Lei, Ming; Yao, Baoli

    2018-02-01

    Fourier ptychography (FP) is a promising computational imaging technique that overcomes the physical space-bandwidth product (SBP) limit of a conventional microscope by applying angular diversity illuminations. However, to date, the effective imaging numerical aperture (NA) achievable with a commercial LED board is still limited to the range of 0.3-0.7 with a 4×/0.1NA objective due to the constraint of planar geometry with weak illumination brightness and attenuated signal-to-noise ratio (SNR). Thus the highest achievable half-pitch resolution is usually constrained between 500-1000 nm, which cannot fulfill some needs of high-resolution biomedical imaging applications. Although it is possible to improve the resolution by using a higher magnification objective with larger NA instead of enlarging the illumination NA, the SBP is suppressed to some extent, making the FP technique less appealing, since the reduction of field-of-view (FOV) is much larger than the improvement of resolution in this FP platform. Herein, in this paper, we initially present a subwavelength resolution Fourier ptychography (SRFP) platform with a hemispherical digital condenser to provide high-angle programmable plane-wave illuminations of 0.95NA, attaining a 4×/0.1NA objective with the final effective imaging performance of 1.05NA at a half-pitch resolution of 244 nm with a wavelength of 465 nm across a wide FOV of 14.60 mm2 , corresponding to an SBP of 245 megapixels. Our work provides an essential step of FP towards high-NA imaging applications without scarfing the FOV, making it more practical and appealing.

  12. Deep sub-wavelength metrology for advanced defect classification

    Science.gov (United States)

    van der Walle, P.; Kramer, E.; van der Donck, J. C. J.; Mulckhuyse, W.; Nijsten, L.; Bernal Arango, F. A.; de Jong, A.; van Zeijl, E.; Spruit, H. E. T.; van den Berg, J. H.; Nanda, G.; van Langen-Suurling, A. K.; Alkemade, P. F. A.; Pereira, S. F.; Maas, D. J.

    2017-06-01

    Particle defects are important contributors to yield loss in semi-conductor manufacturing. Particles need to be detected and characterized in order to determine and eliminate their root cause. We have conceived a process flow for advanced defect classification (ADC) that distinguishes three consecutive steps; detection, review and classification. For defect detection, TNO has developed the Rapid Nano (RN3) particle scanner, which illuminates the sample from nine azimuth angles. The RN3 is capable of detecting 42 nm Latex Sphere Equivalent (LSE) particles on XXX-flat Silicon wafers. For each sample, the lower detection limit (LDL) can be verified by an analysis of the speckle signal, which originates from the surface roughness of the substrate. In detection-mode (RN3.1), the signal from all illumination angles is added. In review-mode (RN3.9), the signals from all nine arms are recorded individually and analyzed in order to retrieve additional information on the shape and size of deep sub-wavelength defects. This paper presents experimental and modelling results on the extraction of shape information from the RN3.9 multi-azimuth signal such as aspect ratio, skewness, and orientation of test defects. Both modeling and experimental work confirm that the RN3.9 signal contains detailed defect shape information. After review by RN3.9, defects are coarsely classified, yielding a purified Defect-of-Interest (DoI) list for further analysis on slower metrology tools, such as SEM, AFM or HIM, that provide more detailed review data and further classification. Purifying the DoI list via optical metrology with RN3.9 will make inspection time on slower review tools more efficient.

  13. Terahertz Near-Field Imaging Using Enhanced Transmission through a Single Subwavelength Aperture

    Science.gov (United States)

    Ishihara, Kunihiko; Ikari, Tomofumi; Minamide, Hiroaki; Shikata, Jun-ichi; Ohashi, Keishi; Yokoyama, Hiroyuki; Ito, Hiromasa

    2005-07-01

    We demonstrate terahertz (THz) near-field imaging using resonantly enhanced transmission of THz-wave radiation (λ˜ 200 μm) through a bull’s eye structure (a single subwavelength aperture surrounded by concentric periodic grooves in a metal plate). The bull’s eye structure shows extremely large enhanced transmission, which has the advantage for a single subwavelength aperture. The spatial resolution for the bull’s eye structure (with an aperture diameter d=100 μm) is evaluated in the near-field region, and a resolution of 50 μm (corresponding to λ/4) is achieved. We obtain the THz near-field images of the subwavelength metal pattern with a spatial resolution below the diffraction limit.

  14. Light-induced attractive force between two metal bodies separated by a subwavelength slit

    International Nuclear Information System (INIS)

    Nesterov, Vladimir; Frumin, Leonid

    2011-01-01

    A novel light-induced attractive force which acts as a force with negative light pressure has been revealed. The force arises by the interaction of plasmon polaritons which are excited at the surface of metal when a transverse magnetic mode propagates through a subwavelength slit between two metal bodies. The estimation of the repulsive force acting on the metal walls of the slit in the case of subwavelength TE mode propagation along the slit is presented. The explicit analytical expressions of light-induced forces between two macroscopic metal bodies or films separated by a subwavelength slit have been derived. These forces could be used to manipulate metallic macro-, micro- and nano-objects in vacuum or in a dielectric medium. Estimations of these light-induced forces show that the forces are sufficient for measurements and practical applications

  15. Electromagnetic reciprocity in antenna theory

    CERN Document Server

    Stumpf, Martin

    2018-01-01

    The reciprocity theorem is among the most intriguing concepts in wave field theory and has become an integral part of almost all standard textbooks on electromagnetic (EM) theory. This book makes use of the theorem to quantitatively describe EM interactions concerning general multiport antenna systems. It covers a general reciprocity-based description of antenna systems, their EM scattering properties, and further related aspects. Beginning with an introduction to the subject, Electromagnetic Reciprocity in Antenna Theory provides readers first with the basic prerequisites before offering coverage of the equivalent multiport circuit antenna representations, EM coupling between multiport antenna systems and their EM interactions with scatterers, accompanied with the corresponding EM compensation theorems.

  16. Antenna theory analysis and design

    CERN Document Server

    Balanis, Constantine A

    2005-01-01

    The discipline of antenna theory has experienced vast technological changes. In response, Constantine Balanis has updated his classic text, Antenna Theory, offering the most recent look at all the necessary topics. New material includes smart antennas and fractal antennas, along with the latest applications in wireless communications. Multimedia material on an accompanying CD presents PowerPoint viewgraphs of lecture notes, interactive review questions, Java animations and applets, and MATLAB features. Like the previous editions, Antenna Theory, Third Edition meets the needs of e

  17. A numerical investigation of sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    The sub-wavelength resonances, known to exist in metamaterial radiators and scatterers of circular cylindrical shape, are investigated with the aim of determining if these resonances also exist for polygonal cylinders and, if so, how they are affected by the shape of the polygon. To this end, a set...... of polygonal cylinders excited by a nearby electric line current is analyzed numerically and it is shown, through detailed analysis of the near-field distribution and radiation resistance, that these polygonal cylinders do indeed support sub-wavelength resonances similar to those of the circular cylinders...

  18. Multiple Antenna Systems with Inherently Decoupled Radiators

    DEFF Research Database (Denmark)

    Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund

    2012-01-01

    In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both Planar Inverted F Antenna (PIFA) and Inverted F Antennas (IFA) were investigated in different UMTS frequency...

  19. Broadband Monopole Antenna

    Science.gov (United States)

    2017-09-14

    December 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] United States Patent Application Ser. No. 15/220,692 filed on July 27, 2016 is incorporated by...antenna operating near 2.5 GHz to obtain an octave of bandwidth. One solution for this is given by Werner et al. in United States Patent

  20. High speed low power optical detection of sub-wavelength scatterer

    NARCIS (Netherlands)

    Roy, S.; Bouwens, M.A.J.; Wei, L.; Pereira, S.F.; Urbach, H.P.; Walle, P. van der

    2015-01-01

    Optical detection of scatterers on a flat substrate, generally done using dark field microscopy technique, is challenging since it requires high power illumination to obtain sufficient SNR (Signal to Noise Ratio) to be able to detect sub-wavelength particles. We developed a bright field technique,

  1. Ultradense, Deep Subwavelength Nanowire Array Photovoltaics As Engineered Optical Thin Films

    KAUST Repository

    Tham, Douglas; Heath, James R.

    2010-01-01

    A photovoltaic device comprised of an array of 20 nm wide, 32 nm pitch array of silicon nanowires is modeled as an optical material. The nanowire array (NWA) has characteristic device features that are deep in the subwavelength regime for light

  2. Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths

    DEFF Research Database (Denmark)

    Boltasseva, Alexandra; Volkov, V.S.; Nielsen, Rasmus Bundgaard

    2008-01-01

    We report on subwavelength plasmon-polariton guiding by triangular metal wedges at telecom wavelengths. A high-quality fabrication procedure for making gold wedge waveguides, which is also mass- production compatible offering large-scale parallel fabrication of plasmonic components, is developed...

  3. Terahertz imaging of sub-wavelength particles with Zenneck surface waves

    Czech Academy of Sciences Publication Activity Database

    Navarro-Cia, M.; Natrella, M.; Dominec, Filip; Delagnes, J.C.; Kužel, Petr; Mounaix, P.; Graham, C.; Renaud, C.C.; Seeds, A.J.; Mitrofanov, O.

    2013-01-01

    Roč. 103, č. 22 (2013), "221103-1"-"221103-5" ISSN 0003-6951 Institutional support: RVO:68378271 Keywords : terahertz * near-field * Zenneck plasmon * sub-wavelength * imaging Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.515, year: 2013

  4. Effective medium approximation for deeply subwavelength all-dielectric multilayers: when does it break down?

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Zhukovsky, Sergei; Andryieuski, Andrei

    2016-01-01

    with different layers ordering and different but still deeply subwavelength thicknesses. Such big reflectance difference values resulted from the special geometrical configuration with an additional resonator layer underneath the multilayers employed for the enhancement of the effect. Our results are important...

  5. Reflectionless tunneling of infrared radiation through subwavelength slit in a waveguide

    Czech Academy of Sciences Publication Activity Database

    Shvartsburg, A. B.; Kuzmiak, Vladimír

    2010-01-01

    Roč. 27, č. 12 (2010), s. 2766-2773 ISSN 0740-3224 Institutional research plan: CEZ:AV0Z20670512 Keywords : wave propagation * tunneling * subwavelength transport Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.095, year: 2010

  6. Omnidirectional luminescence enhancement of fluorescent SiC via pseudoperiodic antireflective subwavelength structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Yakimova, Rositza

    2012-01-01

    In the present work, an approach of fabricating pseudoperiodic antireflective subwavelength structures (ARS) on fluorescent SiC by using self-assembled etch mask is demonstrated. By applying the pseudoperiodic (ARS), the average surface reflectance at 6° incidence over the spectral range of 390...

  7. Phase study of the generated surface plasmon waves in light transmission through a subwavelength aperture

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Xiao, Sanshui; Farzad, Mahmood Hosseini

    2014-01-01

    Interference of surface plasmon (SP) waves plays a key role in light transmission through a subwavelength aperture surrounded by groove structures. In order to characterize interference of the hole and groove-generated SP waves, their phase information was carefully investigated using finite diff...

  8. Antenna conditioning with insulating antenna tiles in Phaedrus-T

    International Nuclear Information System (INIS)

    Intrator, T.; Probert, P.; Doczy, M.; Diebold, D.; Brouchous, D.

    1994-01-01

    In the course of our Alfven wave heating and current drive experiments several different two and four strap antennas have been installed in Phaedrus-T. The motivation focusing the redesign of the antenna into a four strap design was to enable traveling wave phasing, and to reduce the k parallel ∼0 component of the wavenumber spectrum, and consequent edge power deposition. The latest modifications to the 4 strap antenna have dramatically improved its behavior, and enabled us to suppress its RF power induced impurity generation. The remaining gas reflux fueling is significant and is not local to the antenna

  9. Stretchable antenna for wearable electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-04-13

    Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

  10. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

  11. Efficient Placement of Directional Antennas

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory

    2010-09-20

    Directional antenna is an technology for the proliferation of wireless networks. In centralized wireless network, wireless devices communicate through base stations. Directed antennas are placed on base stations and form a backbone of communication. The communication between base stations and wireless devices can be interfered due to a large number of wireless device. Methodically positioning and orienting directed antennas can help to reduce the interference while saving energy. An integer linear programming is developed for siting and directing antennas on multiple base stations, and this formulation can be extended to model non-overlapping channels. Through the integer programming formulation, optimal antenna positions can be used to analyze the performance of directed antennas with different parameters like the number base stations and the number of non-overlapping channels.

  12. Minimum Q Electrically Small Antennas

    DEFF Research Database (Denmark)

    Kim, O. S.

    2012-01-01

    Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

  13. Ultra wide band antennas

    CERN Document Server

    Begaud, Xavier

    2013-01-01

    Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recog

  14. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular...... antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...

  15. Ultra wideband antennas design, methodologies, and performance

    CERN Document Server

    Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto

    2015-01-01

    Ultra Wideband Antennas: Design, Methodologies, and Performance presents the current state of the art of ultra wideband (UWB) antennas, from theory specific for these radiators to guidelines for the design of omnidirectional and directional UWB antennas. Offering a comprehensive overview of the latest UWB antenna research and development, this book:Discusses the developed theory for UWB antennas in frequency and time domainsDelivers a brief exposition of numerical methods for electromagnetics oriented to antennasDescribes solid-planar equivalen

  16. Terahertz-wave near-field imaging with subwavelength resolution using surface-wave-assisted bow-tie aperture

    Science.gov (United States)

    Ishihara, Kunihiko; Ohashi, Keishi; Ikari, Tomofumi; Minamide, Hiroaki; Yokoyama, Hiroyuki; Shikata, Jun-ichi; Ito, Hiromasa

    2006-11-01

    We demonstrate the terahertz-wave near-field imaging with subwavelength resolution using a bow-tie shaped aperture surrounded by concentric periodic structures in a metal film. A subwavelength aperture with concentric periodic grooves, which are known as a bull's eye structure, shows extremely large enhanced transmission beyond the diffraction limit caused by the resonant excitation of surface waves. Additionally, a bow-tie aperture exhibits extraordinary field enhancement at the sharp tips of the metal, which enhances the transmission and the subwavelength spatial resolution. We introduced a bow-tie aperture to the bull's eye structure and achieved high spatial resolution (˜λ/17) in the near-field region. The terahertz-wave near-field image of the subwavelength metal pattern (pattern width=20μm) was obtained for the wavelength of 207μm.

  17. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  18. Antennas for light and plasmons

    NARCIS (Netherlands)

    Dikken, D.J.W.

    2015-01-01

    Antennas have been used for over a century as emitters, scatterers and receivers of electromagnetic waves. All wireless communication devices, such as radio, mobile phones and satellite communication are strongly dependent on the capability of an antenna to localize propagating electromagnetic waves

  19. Optically Controlled Phased Array Antenna

    National Research Council Canada - National Science Library

    Garafalo, David

    1998-01-01

    .... The antenna is a 3-foot by 9 foot phased array capable of a scan angle of 120 degrees. The antenna was designed to be conformal to the cargo door of a large aircraft and is designed to operate in the frequency range of 830 - 1400 MHz with a 30...

  20. Backfire antennas with dipole elements

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø; Pontoppidan, Knud

    1970-01-01

    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...

  1. Slot-Coupled Barbel Antenna

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

  2. DEA deformed stretchable patch antenna

    International Nuclear Information System (INIS)

    Jiang, X-J; Jalali Mazlouman, S; Menon, C; Mahanfar, A; Vaughan, R G

    2012-01-01

    A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)

  3. The ICRF antennas for TFTR

    International Nuclear Information System (INIS)

    Hoffman, D.J.; Colestock, P.L.; Gardner, W.L.; Hosea, J.C.; Nagy, A.; Stevens, J.; Swain, D.W.; Wilson, J.R.

    1988-01-01

    Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab

  4. Dual circularly polarized broadside beam antenna based on metasurfaces

    Science.gov (United States)

    Tellechea, A.; Caminita, F.; Martini, E.; Ederra, I.; Teniente, J.; Iriarte, J. C.; Gonzalo, R.; Maci, S.

    2018-02-01

    Design details of a Ku band metasurface (MTS) antenna with dual circularly polarized (CP) broadside radiation is shown in this work. By means of the surface impedance tensor modulation, synchronized propagation of two transversal magnetic (TM) and transverse electric (TE) surface waves (SWs) is ensured in the structure, which contribute to the radiation in broadside direction by the generation of a CP leaky wave. The structure is implemented by elliptical subwavelength metallic elements with a cross-shaped aperture in the center, printed on top of a thin substrate with high permittivity (AD1000 with a thickness of λ0/17). For the experimental validation, the MTS prototype has been excited employing an orthomode transducer composed by a metallic stepped septum inside an air-filled waveguide. Two orthogonal TE11 modes excited with ±90° phase shift in the feed couple with the TM and TE SWs supported by the MTS and generate RHCP or LHCP broadside beam. Experimental results are compared with the simulation predictions. Finally, conclusions are drawn.

  5. Elliptical metasurfaces for cloaking and antenna applications at microwave and terahertz frequencies

    Science.gov (United States)

    Mehrpourbernety, Hossein

    microwave frequencies. In this work, we propose a novel approach to reduce the mutual coupling between two closely spaced strip dipole antennas with the elliptical metasurfaces formed by conformal printed arrays of sub-wavelength periodic elements. We show that by covering each strip with the metasurface cloak, the antennas become invisible to each other and their radiation patterns are restored as if they were isolated. The electromagnetic scattering analysis pertained to the case of antennas with the frequencies far from each other is shown to be as a good approximation of a 2-D metallic strip scattering cancellation problem solved by expressing the incident and scattered fields in terms of radial and angular Mathieu functions, with the use of sheet impedance boundary conditions at the metasurface. In addition, we extend the novel approach based on the concept of mantle cloaking in order to reduce the mutual near-field and far-field coupling between planar antennas in printed technology. To present the idea, we consider two microstrip-fed monopole antennas resonating at slightly different frequencies and show that by cloaking the radiating part of each antenna, the antennas become invisible to each other, and thus, the mutual coupling between the antennas is suppressed drastically. The cloak structure is realized by a conformal elliptical metasurface formed by confocal printed arrays of sub-wavelength periodic elements, partially embedded in the substrate. The presence of the metasurfaces leads to the restoration of the radiation patterns of the antennas as if they were isolated.

  6. Observation of topological edge states of acoustic metamaterials at subwavelength scale

    Science.gov (United States)

    Dai, Hongqing; Jiao, Junrui; Xia, Baizhan; Liu, Tingting; Zheng, Shengjie; Yu, Dejie

    2018-05-01

    Topological states are of key importance for acoustic wave systems owing to their unique transport properties. In this study, we develop a hexagonal array of hexagonal columns with Helmholtz resonators to obtain subwavelength Dirac cones. Rotation operations are performed to open the Dirac cones and obtain acoustic valley vortex states. In addition, we calculate the angular-dependent frequencies for the band edges at the K-point. Through a topological phase transition, the topological phase of pattern A can change into that of pattern B. The calculations for the bulk dispersion curves show that the acoustic metamaterials exhibit BA-type and AB-type topological edge states. Experimental results demonstrate that a sound wave can transmit well along the topological path. This study could reveal a simple approach to create acoustic topological edge states at the subwavelength scale.

  7. A tunable acoustic barrier based on periodic arrays of subwavelength slits

    Directory of Open Access Journals (Sweden)

    Constanza Rubio

    2015-05-01

    Full Text Available The most usual method to reduce undesirable enviromental noise levels during its transmission is the use of acoustic barriers. A novel type of acoustic barrier based on sound transmission through subwavelength slits is presented. This system consists of two rows of periodic repetition of vertical rigid pickets separated by a slit of subwavelength width and with a misalignment between them. Here, both the experimental and the numerical analyses are presented. The acoustic barrier proposed can be easily built and is frequency tunable. The results demonstrated that the proposed barrier can be tuned to mitigate a band noise without excesive barrier thickness. The use of this system as an environmental acoustic barrier has certain advantages with regard to the ones currently used both from the constructive and the acoustical point of view.

  8. Extraordinary mid-infrared transmission of subwavelength holes in gold films

    KAUST Repository

    Yue, Weisheng; Wang, Zhihong; Yang, Yang; Chen, Longqing; Syed, Ahad A.; Wang, Xianbin

    2014-01-01

    Gold (Au) nanoholes are fabricated with electron-beam lithography and used for the investigation of extraordinary transmission in mid-infrared regime. Transmission properties of the nanoholes are studied as the dependence on hole-size. Transmittance spectra are characterized by Fourier transform infrared spectroscopy (FTIR) and enhanced transmittance through the subwavelength holes is observed. The transmission spectra exhibit well-defined maximum and minimum of which the position are determined by the lattice of the hole array. The hole-size primarily influence the transmission intensity and bandwidth of the resonance peak. With an increase of hole-size, while keep lattice constant fixed, the intensity of the resonance peak and the bandwidth increases, which are due to the localized surface plasmons. Numerical simulation for the transmission through the subwavelength holes is performed and the simulated results agree with the experimental observations. Copyright © 2014 American Scientific Publishers.

  9. Extraordinary mid-infrared transmission of subwavelength holes in gold films

    KAUST Repository

    Yue, Weisheng

    2014-04-01

    Gold (Au) nanoholes are fabricated with electron-beam lithography and used for the investigation of extraordinary transmission in mid-infrared regime. Transmission properties of the nanoholes are studied as the dependence on hole-size. Transmittance spectra are characterized by Fourier transform infrared spectroscopy (FTIR) and enhanced transmittance through the subwavelength holes is observed. The transmission spectra exhibit well-defined maximum and minimum of which the position are determined by the lattice of the hole array. The hole-size primarily influence the transmission intensity and bandwidth of the resonance peak. With an increase of hole-size, while keep lattice constant fixed, the intensity of the resonance peak and the bandwidth increases, which are due to the localized surface plasmons. Numerical simulation for the transmission through the subwavelength holes is performed and the simulated results agree with the experimental observations. Copyright © 2014 American Scientific Publishers.

  10. Using a Semiconductor-to-Metal Transition to Control Optical Transmission through Subwavelength Hole Arrays

    Directory of Open Access Journals (Sweden)

    E. U. Donev

    2008-01-01

    Full Text Available We describe a simple configuration in which the extraordinary optical transmission effect through subwavelength hole arrays in noble-metal films can be switched by the semiconductor-to-metal transition in an underlying thin film of vanadium dioxide. In these experiments, the transition is brought about by thermal heating of the bilayer film. The surprising reverse hysteretic behavior of the transmission through the subwavelength holes in the vanadium oxide suggest that this modulation is accomplished by a dielectric-matching condition rather than plasmon coupling through the bilayer film. The results of this switching, including the wavelength dependence, are qualitatively reproduced by a transfer matrix model. The prospects for effecting a similar modulation on a much faster time scale by using ultrafast laser pulses to trigger the semiconductor-to-metal transition are also discussed.

  11. Evolutionary optimization of compact dielectric lens for farfield sub-wavelength imaging

    DEFF Research Database (Denmark)

    Zhang, Jingjing

    2015-01-01

    The resolution of conventional optical lenses is limited by diffraction. For decades researchers have made various attempts to beat the diffraction limit and realize subwavelength imaging. Here we present the approach to design modified solid immersion lenses that deliver the subwavelength...... information of objects into the far field, yielding magnified images. The lens is composed of an isotropic dielectric core and anisotropic or isotropic dielectric matching layers. It is designed by combining a transformation optics forward design with an inverse design scheme, where an evolutionary...... optimization procedure is applied to find the material parameters for the matching layers. Notably, the total radius of the lens is only 2.5 wavelengths and the resolution can reach lambda/6. Compared to previous approaches based on the simple discretized approximation of a coordinate transformation design...

  12. Subwavelength wave manipulation in a thin surface-wave bandgap crystal.

    Science.gov (United States)

    Gao, Zhen; Wang, Zhuoyuan; Zhang, Baile

    2018-01-01

    It has been recently reported that the unit cell of wire media metamaterials can be tailored locally to shape the flow of electromagnetic waves at deep-subwavelength scales [Nat. Phys.9, 55 (2013)NPAHAX1745-247310.1038/nphys2480]. However, such bulk structures have a thickness of at least the order of wavelength, thus hindering their applications in the on-chip compact plasmonic integrated circuits. Here, based upon a Sievenpiper "mushroom" array [IEEE Trans. Microwave Theory Tech.47, 2059 (1999)IETMAB0018-948010.1109/22.798001], which is compatible with standard printed circuit board technology, we propose and experimentally demonstrate the subwavelength manipulation of surface waves on a thin surface-wave bandgap crystal with a thickness much smaller than the wavelength (1/30th of the operating wavelength). Functional devices including a T-shaped splitter and sharp bend are constructed with good performance.

  13. A tunable acoustic barrier based on periodic arrays of subwavelength slits

    Science.gov (United States)

    Rubio, Constanza; Uris, Antonio; Candelas, Pilar; Belmar, Francisco; Gomez-Lozano, Vicente

    2015-05-01

    The most usual method to reduce undesirable enviromental noise levels during its transmission is the use of acoustic barriers. A novel type of acoustic barrier based on sound transmission through subwavelength slits is presented. This system consists of two rows of periodic repetition of vertical rigid pickets separated by a slit of subwavelength width and with a misalignment between them. Here, both the experimental and the numerical analyses are presented. The acoustic barrier proposed can be easily built and is frequency tunable. The results demonstrated that the proposed barrier can be tuned to mitigate a band noise without excesive barrier thickness. The use of this system as an environmental acoustic barrier has certain advantages with regard to the ones currently used both from the constructive and the acoustical point of view.

  14. Sub-wavelength surface gratings for light redirection in transparent substrates

    DEFF Research Database (Denmark)

    Buss, Thomas; Smith, Cameron; Christiansen, Mads Brøkner

    2012-01-01

    We demonstrate sub-wavelength grating couplers patterned on glass surfaces which are designed to convert incident free-space radiation into guided modes along the glass material. The devices are fabricated by nanoimprint lithography and the measured optical performance is compared to a simple mod...... panes and display applications with minimal influence on vision quality. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4738777]...

  15. Ultrafast optical control of terahertz surface plasmons in subwavelength hole-arrays at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Abul Kalam [Los Alamos National Laboratory; Chen, Hou - Tong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John [Los Alamos National Laboratory

    2010-12-10

    Extraordinary optical transmission through subwavelength metallic hole-arrays has been an active research area since its first demonstration. The frequency selective resonance properties of subwavelength metallic hole arrays, generally known as surface plasmon polaritons, have potential use in functional plasmonic devices such as filters, modulators, switches, etc. Such plasmonic devices are also very promising for future terahertz applications. Ultrafast switching or modulation of the resonant behavior of the 2-D metallic arrays in terahertz frequencies is of particular interest for high speed communication and sensing applications. In this paper, we demonstrate optical control of surface plasmon enhanced resonant terahertz transmission in two-dimensional subwavelength metallic hole arrays fabricated on gallium arsenide based substrates. Optically pumping the arrays creates a conductive layer in the substrate reducing the terahertz transmission amplitude of both the resonant mode and the direct transmission. Under low optical fluence, the terahertz transmission is more greatly affected by resonance damping than by propagation loss in the substrate. An ErAs:GaAs nanoisland superlattice substrate is shown to allow ultrafast control with a switching recovery time of {approx}10 ps. We also present resonant terahertz transmission in a hybrid plasmonic film comprised of an integrated array of subwavelength metallic islands and semiconductor holes. A large dynamic transition between a dipolar localized surface plasmon mode and a surface plasmon resonance near 0.8 THz is observed under near infrared optical excitation. The reversal in transmission amplitude from a stopband to a passband and up to {pi}/2 phase shift achieved in the hybrid plasmonic film make it promising in large dynamic phase modulation, optical changeover switching, and active terahertz plasmonics.

  16. Deep-Subwavelength Resolving and Manipulating of Hidden Chirality in Achiral Nanostructures.

    Science.gov (United States)

    Zu, Shuai; Han, Tianyang; Jiang, Meiling; Lin, Feng; Zhu, Xing; Fang, Zheyu

    2018-04-24

    The chiral state of light plays a vital role in light-matter interactions and the consequent revolution of nanophotonic devices and advanced modern chiroptics. As the light-matter interaction goes into the nano- and quantum world, numerous chiroptical technologies and quantum devices require precise knowledge of chiral electromagnetic modes and chiral radiative local density of states (LDOS) distributions in detail, which directly determine the chiral light-matter interaction for applications such as chiral light detection and emission. With classical optical techniques failing to directly measure the chiral radiative LDOS, deep-subwavelength imaging and control of circular polarization (CP) light associated phenomena are introduced into the agenda. Here, we simultaneously reveal the hidden chiral electromagnetic mode and acquire its chiral radiative LDOS distribution of a single symmetric nanostructure at the deep-subwavelength scale by using CP-resolved cathodoluminescence (CL) microscopy. The chirality of the symmetric nanostructure under normally incident light excitation, resulting from the interference between the symmetric and antisymmetric modes of the V-shaped nanoantenna, is hidden in the near field with a giant chiral distribution (∼99%) at the arm-ends, which enables the circularly polarized CL emission from the radiative LDOS hot-spot and the following active helicity control at the deep-subwavelength scale. The proposed V-shaped nanostructure as a functional unit is further applied to the helicity-dependent binary encoding and the two-dimensional display applications. The proposed physical principle and experimental configuration can promote the future chiral characterization and manipulation at the deep-subwavelength scale and provide direct guidelines for the optimization of chiral light-matter interactions for future quantum studies.

  17. Surface plasmon polariton Akhmediev Breather in a dielectric-metal-dielectric geometry with subwavelength thickness

    Science.gov (United States)

    Devi, Koijam Monika; Porsezian, K.; Sarma, Amarendra K.

    2018-05-01

    We report Akhmediev Breather solutions in a nonlinear multilayer structure comprising of a metal sandwiched between two semi-infinite dielectric layers with subwavelength thickness. These nonlinear solutions inherit the properties of Surface plasmon polaritons and its dynamics is governed by the Nonlinear Schrodinger equation. The breather evolution is studied for specific values of nonlinear and dispersion parameters. An experimental scheme to observe these breathers is also proposed.

  18. Design and analysis of all-dielectric subwavelength focusing flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-09-01

    In this letter, we numerically designed and experimentally demonstrated a compact photonic structure for the subwavelength focusing of light using all-dielectric absorption-free and nonmagnetic scattering objects distributed in an air medium. In order to design the subwavelength focusing flat lens, an evolutionary algorithm is combined with the finite-difference time-domain method for determining the locations of cylindrical scatterers. During the multi-objective optimization process, a specific objective function is defined to reduce the full width at half maximum (FWHM) and diminish side lobe level (SLL) values of light at the focal point. The time-domain response of the optimized flat lens exhibits subwavelength light focusing with an FWHM value of 0.19λ and an SLL value of 0.23, where λ denotes the operating wavelength of light. Experimental analysis of the proposed flat lens is conducted in a microwave regime and findings exactly verify the numerical results with an FWHM of 0.192λ and an SLL value of 0.311 at the operating frequency of 5.42 GHz. Moreover, the designed flat lens provides a broadband subwavelength focusing effect with a 9% bandwidth covering frequency range of 5.10 GHz-5.58 GHz, where corresponding FWHM values remain under 0.21λ. Also, it is important to note that the designed flat lens structure performs a line focusing effect. Possible applications of the designed structure in telecom wavelengths are speculated upon for future perspectives. Namely, the designed structure can perform well in photonic integrated circuits for different fields of applications such as high efficiency light coupling, imaging and optical microscopy, with its compact size and ability for strong focusing.

  19. Subwavelength atom localization via amplitude and phase control of the absorption spectrum-II

    OpenAIRE

    Kapale, Kishore T.; Zubairy, M. Suhail

    2005-01-01

    Interaction of the internal states of an atom with spatially dependent standing-wave cavity field can impart position information of the atom passing through it leading to subwavelength atom localization. We recently demonstrated a new regime of atom localization [Sahrai {\\it et al.}, Phys. Rev. A {\\bf 72}, 013820 (2005)], namely sub-half-wavelength localization through phase control of electromagnetically induced transparency. This regime corresponds to extreme localization of atoms within a...

  20. Tunable plasmonic enhancement of light scattering and absorption in graphene-coated subwavelength wires

    OpenAIRE

    Riso, Máximo; Cuevas, Mauro; Depine, Ricardo A.

    2015-01-01

    The electromagnetic response of subwavelength wires coated with a graphene monolayer illuminated by a linearly polarized plane waves is investigated. The results show that the scattering and extintion cross-sections of the coated wire can be dramatically enhanced when the incident radiation resonantly excites localized surface plasmons. The enhancements occur for p--polarized incident waves and for excitation frequencies that correspond to complex poles in the coefficients of the multipole ex...

  1. Application of holographic sub-wavelength diffraction gratings for monitoring of kinetics of bioprocesses

    International Nuclear Information System (INIS)

    Tamulevičius, Tomas; Šeperys, Rimas; Andrulevičius, Mindaugas; Kopustinskas, Vitoldas; Meškinis, Šarūnas; Tamulevičius, Sigitas; Mikalayeva, Valeryia; Daugelavičius, Rimantas

    2012-01-01

    Highlights: ► Refractive index sensor based on DLC holographic sub-wavelength period grating. ► Spectroscopic analysis of polarized white light reflected from the grating. ► Control of critical wavelength shift and reflectivity changes. ► Testing of model liquid analyte materials. ► Evaluation of interaction between B. subtilis cells and lysozyme. - Abstract: In this work we present a refractive index (RI) sensor based on a sub-wavelength holographic diffraction grating. The sensor chip was fabricated by dry etching of the finely spaced (d = 428 nm) diffraction grating in SiO x doped diamond like carbon (DLC) film. It is shown that employing a fabricated sensor chip, and using the proposed method of analysis of data, one can inspect kinetics of processes in liquids occurring in the vicinity of the grating surface. The method is based on the spectral composition analysis of polarized polychromatic light reflected from the sub-wavelength diffraction grating. The RI measurement system was tested with different model liquid analytes including 25 wt.%, 50 wt.% sugar water solutions, 10 °C, 50 °C distilled water, also Gram-positive bacteria Bacillus subtilis interaction with ion-permeable channels forming antibiotic gramicidin D and a murolytic enzyme lysozyme. Analysis of the data set of specular reflection spectra enabled us to follow the kinetics of the RI changes in the analyte with millisecond resolution. Detectable changes in the effective RI were not worse than Δn = 10 −4 .

  2. Extraordinary light transmission through opaque thin metal film with subwavelength holes blocked by metal disks.

    Science.gov (United States)

    Li, Wen-Di; Hu, Jonathan; Chou, Stephen Y

    2011-10-10

    We observed that when subwavelength-sized holes in an optically opaque metal film are completely covered by opaque metal disks larger than the holes, the light transmission through the holes is not reduced, but rather enhanced. Particularly we report (i) the observation of light transmission through the holes blocked by the metal disks up to 70% larger than the unblocked holes; (ii) the observation of tuning the light transmission by varying the coupling strength between the blocking disks and the hole array, or by changing the size of the disks and holes; (iii) the observation and simulation that the metal disk blocker can improve light coupling from free space to a subwavelength hole; and (iv) the simulation that shows the light transmission through subwavelength holes can be enhanced, even though the gap between the disk and the metal film is partially connected with a metal. We believe these finding should have broad and significant impacts and applications to optical systems in many fields.

  3. New approach for extraordinary transmission through an array of subwavelength apertures using thin ENNZ metamaterial liners.

    Science.gov (United States)

    Baladi, Elham; Pollock, Justin G; Iyer, Ashwin K

    2015-08-10

    Extraordinary transmission (ET) through a periodic array of subwavelength apertures on a perfect metallic screen has been studied extensively in recent years, and has largely been attributed to diffraction effects, for which the periodicity of the apertures, rather than their dimensions, dominates the response. The transmission properties of the apertures at resonance, on the other hand, are not typically considered 'extraordinary' because they may be explained using more conventional aperture-theoretical mechanisms. This work describes a novel approach for achieving ET in which subwavelength apertures are made to resonate by lining them using thin, epsilon-negative and near-zero (ENNZ) metamaterials. The use of ENNZ metamaterials has recently proven successful in miniaturizing circular waveguides by strongly reducing their natural cutoff frequencies, and the theory is adapted here for the design of subwavelength apertures in a metallic screen. We present simulations and proof-of-concept measurements at microwave frequencies that demonstrate ET for apertures measuring one-quarter of a wavelength in diameter and suggest the potential for even more dramatic miniaturization simply by engineering the ENNZ metamaterial dispersion. The results exhibit a fano-like profile whose frequency varies with the properties of the metamaterial liner, but is independent of period. It is suggested that similar behaviour can be obtained at optical frequencies, where ENNZ metamaterials may be realized using appropriately arranged chains of plasmonic nanoparticles.

  4. Subwavelength elastic joints connecting torsional waveguides to maximize the power transmission coefficient

    Science.gov (United States)

    Lee, Joong Seok; Lee, Il Kyu; Seung, Hong Min; Lee, Jun Kyu; Kim, Yoon Young

    2017-03-01

    Joints with slowly varying tapered shapes, such as linear or exponential profiles, are known to transmit incident wave power efficiently between two waveguides with dissimilar impedances. This statement is valid only when the considered joint length is longer than the wavelengths of the incident waves. When the joint length is shorter than the wavelengths, however, appropriate shapes of such subwavelength joints for efficient power transmission have not been explored much. In this work, considering one-dimensional torsional wave motion in a cylindrical elastic waveguide system, optimal shapes or radial profiles of a subwavelength joint maximizing the power transmission coefficient are designed by a gradient-based optimization formulation. The joint is divided into a number of thin disk elements using the transfer matrix approach and optimal radii of the disks are determined by iterative shape optimization processes for several single or bands of wavenumbers. Due to the subwavelength constraint, the optimized joint profiles were found to be considerably different from the slowly varying tapered shapes. Specifically, for bands of wavenumbers, peculiar gourd-like shapes were obtained as optimal shapes to maximize the power transmission coefficient. Numerical results from the proposed optimization formulation were also experimentally realized to verify the validity of the present designs.

  5. Frequency scanning microstrip antennas

    DEFF Research Database (Denmark)

    Danielsen, Magnus; Jørgensen, Rolf

    1979-01-01

    The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase......-shift. Experimental results inX-band, in good agreement with the theory, show that it is possible to scan the main lobe an angle ofpm30degby a variation of the frequencypm300MHz, and where the 3 dB beamwidth is less than10deg. The directivity was 14.7 dB, while the gain was 8.1 dB. The efficiency might be improved...

  6. Metamaterial antennas: the most successful metamaterial technology?

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2015-01-01

    The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas.......The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas....

  7. 47 CFR 73.510 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.510 Section 73.510... Noncommercial Educational FM Broadcast Stations § 73.510 Antenna systems. (a) All noncommercial educational... § 73.316 concerning antenna systems contained in subpart B of this part. (b) Directional antenna. No...

  8. Reconfigurable antenna using plasma reflector

    Science.gov (United States)

    Jusoh, Mohd Taufik; Ahmad, Khairol Amali; Din, Muhammad Faiz Md; Hashim, Fakroul Ridzuan

    2018-02-01

    This paper presents the feasibility study and design of plasma implementation in industrial, scientific and medical (ISM) communication band. A reflector antenna with rounded shaped is proposed to collimate beam in particular direction radiated by a quarter wave antenna operating at 2.4GHz. The simulations result has shown that by using plasma as the reflector elements, the gain, directivity and radiation patterns are identical with metal elements with only small different in the broadside direction. The versatility of the antenna is achievable by introducing electrical reconfigurable option to change the beam pattern.

  9. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...... patterns. It can approach 100% as closely as desired, although in practice this may not be an attractive solution. An example with a small endfire array of dipoles shows an efficiency of 93%. Several examples of small conical horn antennas are also given, and they all have absorption efficiencies less than...

  10. Reconfigurable Antenna for Medical Applications

    Directory of Open Access Journals (Sweden)

    Elizabeth RUFUS

    2009-12-01

    Full Text Available Microwave imaging systems offer much promise for biomedical applications such as cancer detection because of their good penetration, non invasive and non ionizing nature and low cost. The resolution is one of the major problems faced in such systems, which can be improved by applying signal processing techniques. The key element for the microwave imaging system is the antenna. This paper present a fractal antenna which has low profile, light weight and is easy to be fabricated. It has been successfully demonstrated to have multiband characteristics. The simulated results show that the proposed antenna has very good radiation characteristics suitable for imaging applications.

  11. Large inflated-antenna system

    Science.gov (United States)

    Hinson, W. F.; Keafer, L. S.

    1984-01-01

    It is proposed that for inflatable antenna systems, technology feasibility can be demonstrated and parametric design and scalability (scale factor 10 to 20) can be validated with an experiment using a 16-m-diameter antenna attached to the Shuttle. The antenna configuration consists of a thin film cone and paraboloid held to proper shape by internal pressure and a self-rigidizing torus. The cone and paraboloid would be made using pie-shaped gores with the paraboloid being coated with aluminum to provide reflectivity. The torus would be constructed using an aluminum polyester composite that when inflated would erect to a smooth shell that can withstand loads without internal pressure.

  12. Electroactive subwavelength gratings (ESWGs) from conjugated polymers for color and intensity modulation

    Science.gov (United States)

    Bhuvana, Thiruvelu; Kim, Byeonggwan; Yang, Xu; Shin, Haijin; Kim, Eunkyoung

    2012-05-01

    Subwavelength gratings with electroactive polymers such as poly(3-hexylthiophene) (P3HT) and poly(3,4-propylenedioxythiophene-phenylene) (P(ProDOT-Ph)) controlled the color intensity for various visible colors of diffracted light in a single device. Under the illumination of a white light, at a fixed angle of incidence, the color intensity of the diffracted light was reversibly switched from the maximum value down to 15% (85% decrease) by applying -2 to 2 V due to electrochemical (EC) reaction. All spectral colors including red, green, and blue were generated by changing the angle of incidence, and the intensity of each color was modulated electrochemically at a single EC device. With electroactive subwavelength gratings (ESWGs) of P3HT, the maximum modulation of the color intensity was observed in the red-yellow quadrant in the CIE color plot, whereas for the ESWGs of P(ProDOT-Ph), the maximum modulation of the color intensity was observed in the yellow-green and green-blue quadrants. Both ESWGs showed a memory effect, keeping their color and intensity even after power was turned off for longer than 40 hours.Subwavelength gratings with electroactive polymers such as poly(3-hexylthiophene) (P3HT) and poly(3,4-propylenedioxythiophene-phenylene) (P(ProDOT-Ph)) controlled the color intensity for various visible colors of diffracted light in a single device. Under the illumination of a white light, at a fixed angle of incidence, the color intensity of the diffracted light was reversibly switched from the maximum value down to 15% (85% decrease) by applying -2 to 2 V due to electrochemical (EC) reaction. All spectral colors including red, green, and blue were generated by changing the angle of incidence, and the intensity of each color was modulated electrochemically at a single EC device. With electroactive subwavelength gratings (ESWGs) of P3HT, the maximum modulation of the color intensity was observed in the red-yellow quadrant in the CIE color plot, whereas for the

  13. Electrically floating, near vertical incidence, skywave antenna

    Science.gov (United States)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  14. Inflatable Antennas Support Emergency Communication

    Science.gov (United States)

    2010-01-01

    Glenn Research Center awarded Small Business Innovation Research (SBIR) contracts to ManTech SRS Technologies, of Newport Beach, California, to develop thin film inflatable antennas for space communication. With additional funding, SRS modified the concepts for ground-based inflatable antennas. GATR (Ground Antenna Transmit and Receive) Technologies, of Huntsville, Alabama, licensed the technology and refined it to become the world s first inflatable antenna certified by the Federal Communications Commission. Capable of providing Internet access, voice over Internet protocol, e-mail, video teleconferencing, broadcast television, and other high-bandwidth communications, the systems have provided communication during the wildfires in California, after Hurricane Katrina in Mississippi, and following the 2010 Haiti earthquake.

  15. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication sa...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  16. Antenna design for mobile devices

    CERN Document Server

    Zhang, Zhijun

    2017-01-01

    - Integrates state-of-the-art technologies with a special section for step-by-step antenna design - Features up-to-date bio-safety and electromagnetic compatibility regulation compliance and latest standards - Newly updated with MIMO antenna design, measurements and requirements - Accessible to readers of many levels, from introductory to specialist - Written by a practicing expert who has hired and trained numerous engineers

  17. Radar techniques using array antennas

    CERN Document Server

    Wirth, Wulf-Dieter

    2013-01-01

    Radar Techniques Using Array Antennas is a thorough introduction to the possibilities of radar technology based on electronic steerable and active array antennas. Topics covered include array signal processing, array calibration, adaptive digital beamforming, adaptive monopulse, superresolution, pulse compression, sequential detection, target detection with long pulse series, space-time adaptive processing (STAP), moving target detection using synthetic aperture radar (SAR), target imaging, energy management and system parameter relations. The discussed methods are confirmed by simulation stud

  18. Antennas for mobile satellite communications

    Science.gov (United States)

    Huang, John

    1991-12-01

    A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

  19. Development of film antenna for diversity reception; Diversity taio film antenna no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Shigeta, K; Taniguchi, T; Kubota, K [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    Based on the principle of capacitance-loaded window antennas, a new film antenna construction pasting an antenna element on a defogger element printed on a rear window was found. The film antennas show high reception performance, and can be used as television diversity antennas or a VICS-FM multiplex antenna. This paper describes the antenna design concept, the antenna construction and the application to a recreational vehicle which styling is 1.3-Box wagon for the electric accessory. 2 refs., 11 figs.

  20. Some Recent Developments of Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2012-01-01

    Full Text Available Although the microstrip antenna has been extensively studied in the past few decades as one of the standard planar antennas, it still has a huge potential for further developments. The paper suggests three areas for further research based on our previous works on microstrip antenna elements and arrays. One is exploring the variety of microstrip antenna topologies to meet the desired requirement such as ultrawide band (UWB, high gain, miniaturization, circular polarization, multipolarized, and so on. Another is to apply microstrip antenna to form composite antenna which is more potent than the individual antenna. The last is growing towards highly integration of antenna/array and feeding network or operating at relatively high frequencies, like sub-millimeter wave or terahertz (THz wave regime, by using the advanced machining techniques. To support our points of view, some examples of antennas developed in our group are presented and discussed.

  1. Antenna for passive RFID tags

    Science.gov (United States)

    Schiopu, Paul; Manea, Adrian; Cristea, Ionica; Grosu, Neculai; Vladescu, Marian; Craciun, Anca-Ileana; Craciun, Alexandru

    2015-02-01

    Minuscule devices, called RFID tags are attached to objects and persons and emit information which positioned readers may capture wirelessly. Many methods of identification have been used, but that of most common is to use a unique serial number for identification of person or object. RFID tags can be characterized as either active or passive [1,2]. Traditional passive tags are typically in "sleep" state until awakened by the reader's emitted field. In passive tags, the reader's field acts to charge the capacitor that powers the badge and this can be a combination of antenna and barcodes obtained with SAW( Surface Acoustic Wave) devices [1,2,3] . The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. The paper contribution are targeted to antenna for passive RFID tags. The electromagnetic field generated by the reader is somehow oriented by the reader antenna and power is induced in the tag only if the orientation of the tag antenna is appropriate. A tag placed orthogonal to the reader yield field will not be read. This is the reason that guided manufacturers to build circular polarized antenna capable of propagating a field that is alternatively polarized on all planes passing on the diffusion axis. Passive RFID tags are operated at the UHF frequencies of 868MHz (Europe) and 915MHz (USA) and at the microwave frequencies of 2,45 GHz and 5,8 GHz . Because the tags are small dimensions, in paper, we present the possibility to use circular polarization microstrip antenna with fractal edge [2].

  2. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  3. Antenna Miniaturization with MEMS Tunable Capacitors

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

  4. Application of holographic sub-wavelength diffraction gratings for monitoring of kinetics of bioprocesses

    Energy Technology Data Exchange (ETDEWEB)

    Tamulevicius, Tomas, E-mail: tomas.tamulevicius@ktu.lt [Institute of Materials Science of Kaunas University of Technology, Savanoriu Ave. 271, LT-50131, Kaunas (Lithuania); Seperys, Rimas; Andrulevicius, Mindaugas; Kopustinskas, Vitoldas; Meskinis, Sarunas; Tamulevicius, Sigitas [Institute of Materials Science of Kaunas University of Technology, Savanoriu Ave. 271, LT-50131, Kaunas (Lithuania); Mikalayeva, Valeryia; Daugelavicius, Rimantas [Department of Biochemistry and Biotechnologies of Vytautas Magnus University, Vileikos St. 8, LT-44404 Kaunas (Lithuania)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Refractive index sensor based on DLC holographic sub-wavelength period grating. Black-Right-Pointing-Pointer Spectroscopic analysis of polarized white light reflected from the grating. Black-Right-Pointing-Pointer Control of critical wavelength shift and reflectivity changes. Black-Right-Pointing-Pointer Testing of model liquid analyte materials. Black-Right-Pointing-Pointer Evaluation of interaction between B. subtilis cells and lysozyme. - Abstract: In this work we present a refractive index (RI) sensor based on a sub-wavelength holographic diffraction grating. The sensor chip was fabricated by dry etching of the finely spaced (d = 428 nm) diffraction grating in SiO{sub x} doped diamond like carbon (DLC) film. It is shown that employing a fabricated sensor chip, and using the proposed method of analysis of data, one can inspect kinetics of processes in liquids occurring in the vicinity of the grating surface. The method is based on the spectral composition analysis of polarized polychromatic light reflected from the sub-wavelength diffraction grating. The RI measurement system was tested with different model liquid analytes including 25 wt.%, 50 wt.% sugar water solutions, 10 Degree-Sign C, 50 Degree-Sign C distilled water, also Gram-positive bacteria Bacillus subtilis interaction with ion-permeable channels forming antibiotic gramicidin D and a murolytic enzyme lysozyme. Analysis of the data set of specular reflection spectra enabled us to follow the kinetics of the RI changes in the analyte with millisecond resolution. Detectable changes in the effective RI were not worse than {Delta}n = 10{sup -4}.

  5. Subwavelength Gold Grating as Polarizers Integrated with InP-Based InGaAs Sensors.

    Science.gov (United States)

    Wang, Rui; Li, Tao; Shao, Xiumei; Li, Xue; Huang, Xiaqi; Shao, Jinhai; Chen, Yifang; Gong, Haimei

    2015-07-08

    There are currently growing needs for polarimetric imaging in infrared wavelengths for broad applications in bioscience, communications and agriculture, etc. Subwavelength metallic gratings are capable of separating transverse magnetic (TM) mode from transverse electric (TE) mode to form polarized light, offering a reliable approach for the detection in polarization way. This work aims to design and fabricate subwavelength gold gratings as polarizers for InP-based InGaAs sensors in 1.0-1.6 μm. The polarization capability of gold gratings on InP substrate with pitches in the range of 200-1200 nm (fixed duty cycle of 0.5) has been systematically studied by both theoretical modeling with a finite-difference time-domain (FDTD) simulator and spectral measurements. Gratings with 200 nm lines/space in 100-nm-thick gold have been fabricated by electron beam lithography (EBL). It was found that subwavelength gold gratings directly integrated on InP cannot be applied as good polarizers, because of the existence of SPP modes in the detection wavelengths. An effective solution has been found by sandwiching the Au/InP bilayer using a 200 nm SiO2 layer, leading to significant improvement in both TM transmission and extinction ratio. At 1.35 μm, the improvement factors are 8 and 10, respectively. Therefore, it is concluded that the Au/SiO2/InP trilayer should be a promising candidate of near-infrared polarizers for the InP-based InGaAs sensors.

  6. Light polarization management via reflection from arrays of sub-wavelength metallic twisted bands

    Science.gov (United States)

    Nawrot, M.; Haberko, J.; Zinkiewicz, Ł.; Wasylczyk, P.

    2017-12-01

    With constant progress of nano- and microfabrication technologies, photolithography in particular, a number of sub-wavelength metallic structures have been demonstrated that can be used to manipulate light polarization. Numerical simulations of light propagation hint that helical twisted bands can have interesting polarization properties. We use three-dimensional two-photon photolithography (direct laser writing) to fabricate a few-micrometer-thick arrays of twisted bands and coat them uniformly with metal. We demonstrate that circular polarization can be generated from linear polarization upon reflection from such structures over a broad range of frequencies in the mid infrared.

  7. Pseudo-Rhombus-Shaped Subwavelength Crossed Gratings of GaAs for Broadband Antireflection

    International Nuclear Information System (INIS)

    Chen Xi; Zhang Jing; Song Guo-Feng; Chen Liang-Hui; Fan Zhong-Chao

    2010-01-01

    Holographic lithography coupled with the nonlinear response of photoresist to the exposure is adopted to fabricate porous photoresist (PR) mask. Conventional dot PR mask is also generated, and both patterns are transferred into a underlying GaAs substrate by the optimal dry etching process to obtain tapered subwavelength crossed gratings (SWCGs) to mimic the moth-eye structure. In comparison of the experiment and simulation, the closely-packed pseudo-rhombus-shaped GaAs SWCGs resulting from the porous mask outperforms the conical counterpart which comes from the dot mask, and achieves a reported lowest mean spectral reflectance of 1.1%. (fundamental areas of phenomenology(including applications))

  8. Experimental Demonstration of Effective Medium Approximation Breakdown in Deeply Subwavelength All-Dielectric Multilayers

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Andryieuski, Andrei; Takayama, Osamu

    2015-01-01

    We report the first experimental demonstration of anomalous breakdown of the effective medium approximation in all-dielectric deeply subwavelength thickness (d∼λ/160-λ/30) multilayers, as recently predicted theoretically [H. H. Sheinfux et al., Phys. Rev. Lett. 113, 243901 (2014)]. Multilayer...... stacks are composed of alternating alumina and titania layers fabricated using atomic layer deposition. For light incident on such multilayers at angles near the total internal reflection, we observe pronounced differences in the reflectance spectra for structures with 10- vs 20-nm thick layers, as well...

  9. Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances

    KAUST Repository

    Zhao, Jiajun

    2017-07-06

    Sound emission is inefficient at low frequencies as limited by source size. This letter presents enhancing emission of monochromatic monopole and multipole sources by enclosing the source with a subwavelength circular enclosure filled of an anisotropic material of a low radial sound speed. The anisotropy is associated with an infinite tangential density along the azimuth. Numerical simulations show that emission gain is produced at frequencies surrounding degenerate Mie resonant frequencies of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.

  10. Controlling material birefringence in sapphire via self-assembled, sub-wavelength defects

    Science.gov (United States)

    Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

    2018-02-01

    Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Generally, this is an intrinsic optical property of a material and cannot be altered. Here, we report a novel technique—direct laser writing—that enables us to control the natural, material birefringence of sapphire over a broad range of wavelengths. The broadband form birefringence originating from self-assembled, periodic array of sub-wavelength (˜ 50-200 nm) defects created by laser writing, can enhance, suppress or maintain the material birefringence of sapphire without affecting its transparency range in visible or its surface quality.

  11. Design of a Binary Grating with Subwavelength Features that Acts as a Polarizing Beam Splitter.

    Science.gov (United States)

    Pajewski, L; Borghi, R; Schettini, G; Frezza, F; Santarsiero, M

    2001-11-10

    A binary diffractive optical element, acting as a polarizing beam splitter, is proposed and analyzed. It behaves like a transmissive blazed grating, working on the first or the second diffraction order, depending on the polarization state of the incident radiation. The grating-phase profile required for both polarization states is obtained by means of suitably sized subwavelength groups etched in an isotropic dielectric medium. A rigorous electromagnetic analysis of the grating is presented, and numerical results concerning its performances in terms of diffraction efficiency as well as frequency and angular bandwidths are provided.

  12. Converting a Monopole Emission into a Dipole Using a Subwavelength Structure

    Science.gov (United States)

    Fan, Xu-Dong; Zhu, Yi-Fan; Liang, Bin; Cheng, Jian-chun; Zhang, Likun

    2018-03-01

    High-efficiency emission of multipoles is unachievable by a source much smaller than the wavelength, preventing compact acoustic devices for generating directional sound beams. Here, we present a primary scheme towards solving this problem by numerically and experimentally enclosing a monopole sound source in a structure with a dimension of around 1 /10 sound wavelength to emit a dipolar field. The radiated sound power is found to be more than twice that of a bare dipole. Our study of efficient emission of directional low-frequency sound from a monopole source in a subwavelength space may have applications such as focused ultrasound for imaging, directional underwater sound beams, miniaturized sonar, etc.

  13. The Subwavelength Optical Field Confinement in a Multilayered Microsphere with Quasiperiodic Spherical Stack

    Directory of Open Access Journals (Sweden)

    Gennadiy N. Burlak

    2008-01-01

    Full Text Available We study the frequency spectrum of nanoemitters placed in a microsphere with a quasiperiodic subwavelength spherical stack. The spectral evolution of transmittancy at the change of thickness of two-layer blocks, constructed following the Fibonacci sequence, is investigated. When the number of layers (Fibonacci order increases, the structure of spectrum acquires a fractal form. Our calculations show the radiation confinement and gigantic field enhancement, when the ratio of layers’ widths in twolayer blocks of the stack is close to the golden mean value.

  14. Experimental demonstration of tunable directional excitation of surface plasmon polaritons with a subwavelength metallic double slit

    Science.gov (United States)

    Li, Xiaowei; Tan, Qiaofeng; Bai, Benfeng; Jin, Guofan

    2011-06-01

    We demonstrate experimentally the directional excitation of surface plasmon polaritons (SPPs) on a metal film by a subwavelength double slit under backside illumination, based on the interference of SPPs generated by the two slits. By varying the incident angle, the SPPs can be tunably directed into two opposite propagating directions with a predetermined splitting ratio. Under certain incident angle, unidirectional SPP excitation can be achieved. This compact directional SPP coupler is potentially useful for many on-chip applications. As an example, we show the integration of the double-slit couplers with SPP Bragg mirrors, which can effectively realize selective coupling of SPPs into different ports in an integrated plasmonic chip.

  15. Visible Wavelength Color Filters Using Dielectric Subwavelength Gratings for Backside-Illuminated CMOS Image Sensor Technologies.

    Science.gov (United States)

    Horie, Yu; Han, Seunghoon; Lee, Jeong-Yub; Kim, Jaekwan; Kim, Yongsung; Arbabi, Amir; Shin, Changgyun; Shi, Lilong; Arbabi, Ehsan; Kamali, Seyedeh Mahsa; Lee, Hong-Seok; Hwang, Sungwoo; Faraon, Andrei

    2017-05-10

    We report transmissive color filters based on subwavelength dielectric gratings that can replace conventional dye-based color filters used in backside-illuminated CMOS image sensor (BSI CIS) technologies. The filters are patterned in an 80 nm-thick poly silicon film on a 115 nm-thick SiO 2 spacer layer. They are optimized for operating at the primary RGB colors, exhibit peak transmittance of 60-80%, and have an almost insensitive response over a ± 20° angular range. This technology enables shrinking of the pixel sizes down to near a micrometer.

  16. Subwavelength atom localization via amplitude and phase control of the absorption spectrum

    OpenAIRE

    Sahrai, Mostafa; Tajalli, Habib; Kapale, Kishore T.; Zubairy, M. Suhail

    2005-01-01

    We propose a scheme for subwavelength localization of an atom conditioned upon the absorption of a weak probe field at a particular frequency. Manipulating atom-field interaction on a certain transition by applying drive fields on nearby coupled transitions leads to interesting effects in the absorption spectrum of the weak probe field. We exploit this fact and employ a four-level system with three driving fields and a weak probe field, where one of the drive fields is a standing-wave field o...

  17. Polarization control of non-diffractive helical optical beams through subwavelength metallic apertures

    International Nuclear Information System (INIS)

    Lombard, E; Genet, C; Ebbesen, T W; Drezet, A

    2010-01-01

    We demonstrate experimentally a simple method for preparing non-diffractive vectorial optical beams that can display wave-front helicity. This method is based on space-variant modifications of the polarization of an optical beam transmitted through subwavelength annular rings perforating opaque metal films. We show how the description of the optical properties of such structures must account for the vectorial character of the polarization and how, in turn, these properties can be controlled by straightforward sequences of preparation and analysis of polarization states.

  18. Design of LTCC Based Fractal Antenna

    KAUST Repository

    AdbulGhaffar, Farhan

    2010-09-01

    The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

  19. Design and optimization of a high-efficiency array generator in the mid-IR with binary subwavelength grooves.

    Science.gov (United States)

    Bloom, Guillaume; Larat, Christian; Lallier, Eric; Lee-Bouhours, Mane-Si Laure; Loiseaux, Brigitte; Huignard, Jean-Pierre

    2011-02-10

    We have designed a high-efficiency array generator composed of subwavelength grooves etched in a GaAs substrate for operation at 4.5 μm. The method used combines rigorous coupled wave analysis with an optimization algorithm. The optimized beam splitter has both a high efficiency (∼96%) and a good intensity uniformity (∼0.2%). The fabrication error tolerances are numerically calculated, and it is shown that this subwavelength array generator could be fabricated with current electron beam writers and inductively coupled plasma etching. Finally, we studied the effect of a simple and realistic antireflection coating on the performance of the beam splitter.

  20. Spatially dispersive finite-difference time-domain analysis of sub-wavelength imaging by the wire medium slabs

    Science.gov (United States)

    Zhao, Yan; Belov, Pavel A.; Hao, Yang

    2006-06-01

    In this paper, a spatially dispersive finite-difference time-domain (FDTD) method to model wire media is developed and validated. Sub-wavelength imaging properties of the finite wire medium slabs are examined. It is demonstrated that the slab with its thickness equal to an integer number of half-wavelengths is capable of transporting images with sub-wavelength resolution from one interface of the slab to another. It is also shown that the operation of such transmission devices is not sensitive to their transverse dimensions, which can be made even comparable to the wavelength. In this case, the edge diffractions are negligible and do not disturb the image formation.

  1. Compact Low Frequency Radio Antenna

    Science.gov (United States)

    Punnoose, Ratish J.

    2008-11-11

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  2. Biogenic Amines in Insect Antennae

    Directory of Open Access Journals (Sweden)

    Marianna I. Zhukovskaya

    2017-06-01

    Full Text Available Insect antenna is a multisensory organ, each modality of which can be modulated by biogenic amines. Octopamine (OA and its metabolic precursor tyramine (TA affect activity of antennal olfactory receptor neurons. There is some evidence that dopamine (DA modulates gustatory neurons. Serotonin can serve as a neurotransmitter in some afferent mechanosensory neurons and both as a neurotransmitter and neurohormone in efferent fibers targeted at the antennal vessel and mechanosensory organs. As a neurohormone, serotonin affects the generation of the transepithelial potential by sensillar accessory cells. Other possible targets of biogenic amines in insect antennae are hygro- and thermosensory neurons and epithelial cells. We suggest that the insect antenna is partially autonomous in the sense that biologically active substances entering its hemolymph may exert their effects and be cleared from this compartment without affecting other body parts.

  3. Design of LTCC Based Fractal Antenna

    KAUST Repository

    AdbulGhaffar, Farhan

    2010-01-01

    The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array

  4. Wireless interrogation of passive antenna sensors

    International Nuclear Information System (INIS)

    Deshmukh, S; Huang, H

    2010-01-01

    Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range

  5. Statistical monitoring of linear antenna arrays

    KAUST Repository

    Harrou, Fouzi; Sun, Ying

    2016-01-01

    The paper concerns the problem of monitoring linear antenna arrays using the generalized likelihood ratio (GLR) test. When an abnormal event (fault) affects an array of antenna elements, the radiation pattern changes and significant deviation from

  6. Accurate determination of antenna directivity

    DEFF Research Database (Denmark)

    Dich, Mikael

    1997-01-01

    The derivation of a formula for accurate estimation of the total radiated power from a transmitting antenna for which the radiated power density is known in a finite number of points on the far-field sphere is presented. The main application of the formula is determination of directivity from power......-pattern measurements. The derivation is based on the theory of spherical wave expansion of electromagnetic fields, which also establishes a simple criterion for the required number of samples of the power density. An array antenna consisting of Hertzian dipoles is used to test the accuracy and rate of convergence...

  7. Mobile Phone Antenna Performance 2016

    DEFF Research Database (Denmark)

    Pedersen, Gert F.

    This study investigates the antenna performance of a number of mobile phones widely used in the Nordic Countries. The study is supported by the Nordic Council of Ministers. The antenna performance of the phones is vital for the phones ability to ensure radio coverage in low signal situations....... The study is based on the mobile systems in the Nordic mobile networks and on both speech and data services. The selected phone models are among the most popular new phones at the time of this study....

  8. Estimation of complex permittivity using loop antenna

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2004-01-01

    A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna.......A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna....

  9. System and circuit models for microwave antennas

    OpenAIRE

    Sobhy, Mohammed; Sanz-Izquierdo, Benito; Batchelor, John C.

    2007-01-01

    This paper describes how circuit and system models are derived for antennas from measurement of the input reflection coefficient. Circuit models are used to optimize the antenna performance and to calculate the radiated power and the transfer function of the antenna. System models are then derived for transmitting and receiving antennas. The most important contribution of this study is to show how microwave structures can be integrated into the simulation of digital communication systems. Thi...

  10. Enhancement of the spontaneous emission in subwavelength quasi-two-dimensional waveguides and resonators

    Science.gov (United States)

    Tokman, Mikhail; Long, Zhongqu; AlMutairi, Sultan; Wang, Yongrui; Belkin, Mikhail; Belyanin, Alexey

    2018-04-01

    We consider a quantum-electrodynamic problem of the spontaneous emission from a two-dimensional (2D) emitter, such as a quantum well or a 2D semiconductor, placed in a quasi-2D waveguide or cavity with subwavelength confinement in one direction. We apply the Heisenberg-Langevin approach, which includes dissipation and fluctuations in the electron ensemble and in the electromagnetic field of a cavity on equal footing. The Langevin noise operators that we introduce do not depend on any particular model of dissipative reservoir and can be applied to any dissipation mechanism. Moreover, our approach is applicable to nonequilibrium electron systems, e.g., in the presence of pumping, beyond the applicability of the standard fluctuation-dissipation theorem. We derive analytic results for simple but practically important geometries: strip lines and rectangular cavities. Our results show that a significant enhancement of the spontaneous emission, by a factor of order 100 or higher, is possible for quantum wells and other 2D emitters in a subwavelength cavity.

  11. Application of holographic sub-wavelength diffraction gratings for monitoring of kinetics of bioprocesses

    Science.gov (United States)

    Tamulevičius, Tomas; Šeperys, Rimas; Andrulevičius, Mindaugas; Kopustinskas, Vitoldas; Meškinis, Šarūnas; Tamulevičius, Sigitas; Mikalayeva, Valeryia; Daugelavičius, Rimantas

    2012-09-01

    In this work we present a refractive index (RI) sensor based on a sub-wavelength holographic diffraction grating. The sensor chip was fabricated by dry etching of the finely spaced (d = 428 nm) diffraction grating in SiOx doped diamond like carbon (DLC) film. It is shown that employing a fabricated sensor chip, and using the proposed method of analysis of data, one can inspect kinetics of processes in liquids occurring in the vicinity of the grating surface. The method is based on the spectral composition analysis of polarized polychromatic light reflected from the sub-wavelength diffraction grating. The RI measurement system was tested with different model liquid analytes including 25 wt.%, 50 wt.% sugar water solutions, 10 °C, 50 °C distilled water, also Gram-positive bacteria Bacillus subtilis interaction with ion-permeable channels forming antibiotic gramicidin D and a murolytic enzyme lysozyme. Analysis of the data set of specular reflection spectra enabled us to follow the kinetics of the RI changes in the analyte with millisecond resolution. Detectable changes in the effective RI were not worse than Δn = 10-4.

  12. Bloch-Surface-Polariton-Based Hybrid Nanowire Structure for Subwavelength, Low-Loss Waveguiding

    Directory of Open Access Journals (Sweden)

    Weijing Kong

    2018-03-01

    Full Text Available Surface plasmon polaritons (SPPs have been thoroughly studied in the past decades for not only sensing but also waveguiding applications. Various plasmonic device structures have been explored due to their ability to confine their optical mode to the subwavelength level. However, with the existence of metal, the large ohmic loss limits the propagation distance of the SPP and thus the scalability of such devices. Therefore, different hybrid waveguides have been proposed to overcome this shortcoming. Through fine tuning of the coupling between the SPP and a conventional waveguide mode, a hybrid mode could be excited with decent mode confinement and extended propagation distance. As an effective alternative of SPP, Bloch surface waves have been re-investigated more recently for their unique advantages. As is supported in all-dielectric structures, the optical loss for the Bloch surface wave is much lower, which stands for a much longer propagating distance. Yet, the confinement of the Bloch surface wave due to the reflections and refractions in the multilayer structure is not as tight as that of the SPP. In this work, by integrating a periodic multilayer structure that supports the Bloch surface wave with a metallic nanowire structure, a hybrid Bloch surface wave polariton could be excited. With the proposed hybrid nanowire structure, a hybrid mode is demonstrated with the deep subwavelength mode confinement and a propagation distance of tens of microns.

  13. Tunable dual-band subwavelength imaging with a wire medium slab loaded with nanostructured graphene metasurfaces

    Directory of Open Access Journals (Sweden)

    Ali Forouzmand

    2015-07-01

    Full Text Available In this paper, we demonstrate that a wire medium slab loaded with graphene-nanopatch metasurfaces (GNMs enables the enhancement of evanescent waves for the subwavelength imaging at terahertz (THz frequencies. The analysis is based on the nonlocal homogenization model for wire medium with the additional boundary condition at the connection of wires to graphene. The physical mechanism behind this lens can be described as the surface plasmons excitement at the lower and upper GNMs which are coupled by an array of metallic wires. The dual nature (capacitive/inductive of the GNM is utilized in order to design a dual-band lens in which the unique controllable properties of graphene and the structural parameters of wire medium (WM slab provide more degrees of freedom in controlling two operating frequency bands. The lens can support the subwavelength imaging simultaneously at two tunable distinct frequencies with the resolution better than λ/6 even if the distance between GNMs is a significant fraction of wavelength (>λ/5.5. The major future challenges in the fabrication of the lens have been demonstrated and a promising approach for the practical configuration of the lens has been proposed.

  14. Subwavelength atom localization via amplitude and phase control of the absorption spectrum

    International Nuclear Information System (INIS)

    Sahrai, Mostafa; Tajalli, Habib; Kapale, Kishore T.; Zubairy, M. Suhail

    2005-01-01

    We propose a scheme for subwavelength localization of an atom conditioned upon the absorption of a weak probe field at a particular frequency. Manipulating atom-field interaction on a certain transition by applying drive fields on nearby coupled transitions leads to interesting effects in the absorption spectrum of the weak probe field. We exploit this fact and employ a four-level system with three driving fields and a weak probe field, where one of the drive fields is a standing-wave field of a cavity. We show that the position of an atom along this standing wave is determined when probe-field absorption is measured. We find that absorption of the weak probe field at a certain frequency leads to subwavelength localization of the atom in either of the two half-wavelength regions of the cavity field by appropriate choice of the system parameters. We term this result as sub-half-wavelength localization to contrast it with the usual atom localization result of four peaks spread over one wavelength of the standing wave. We observe two localization peaks in either of the two half-wavelength regions along the cavity axis

  15. Anomalous dispersion properties of TM waves in subwavelength metallic waveguides loaded by uniaxial metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guanghui, E-mail: wanggh@scnu.edu.cn; Lei, Yuandong; Zhang, Weifeng

    2015-02-20

    Dispersion properties of transverse magnetic (TM) waves in a subwavelength metallic waveguide loaded by uniaxial metamaterials are investigated, based on two kinds of uniaxial metamaterials with different orientations of optical axis. The numerical results show that the existence of fundamental TM{sub 0} mode and high-order TM modes in the waveguide system is dependent on the orientation of optical axis. In addition, their anomalous dispersion properties are clarified. When the orientation of optical axis is selected properly, there are two branches of dispersion curves for each high-order mode—one is normal dispersion and another belongs to anomalous dispersion, showing a transition from a backward wave to a forward one with the increase of working frequency. Moreover, the group velocity and energy flow distribution for TM{sub 1} mode are also demonstrated. These properties may have potential applications in optical information storage, integrated optics and nanophotonic devices. - Highlights: • Two kinds of subwavelength uniaxial metamaterial waveguides are constructed. • We demonstrate anomalous dispersion properties of transverse magnetic (TM) guided modes. • There are two branches of dispersion curves for high-order TM modes, showing a transition from a backward wave to a forward one. • Group velocity can approach to zero, having potential application in optical information storage. • Negative group velocity and energy flow distribution for TM modes are shown.

  16. Numerical Study of Planar GPR Antenna Measurements

    DEFF Research Database (Denmark)

    Meincke, Peter; Hansen, Thorkild

    2004-01-01

    The formulation of planar near-field measurements of GPR antennas determines the plane-wave spectra of the GPR antenna in terms of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical study investigates how the formulation is affected by (1...

  17. Theory of antennas for gravitational radiation

    International Nuclear Information System (INIS)

    Hirakawa, Hiromasa; Narihara, Kazumichi; Fujimoto, Masakatsu.

    1976-01-01

    A theory of antennas for gravitational radiation is presented. On the basis of the eigenmode system and the structure symmetry, the emission and reception characteristics and the directivity pattern of antennas are treated. The antenna thermal noise is discussed in connection with the coupling constant of vibration sensors and with the effect of cold-damping. (auth.)

  18. 47 CFR 78.105 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 78.105 Section 78.105... SERVICE Technical Regulations § 78.105 Antenna systems. (a) For fixed stations operating in the 12.7-13.2... planes. (2) New periscope antenna systems will be authorized upon a certification that the radiation, in...

  19. 47 CFR 74.641 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 74.641 Section 74.641... Stations § 74.641 Antenna systems. (a) For fixed stations operating above 2025 MHz, the following standards... elevation planes. (2) New periscope antenna systems will be authorized upon a certification that the...

  20. Collapsible structure for an antenna reflector

    Science.gov (United States)

    Trubert, M. R. (Inventor)

    1973-01-01

    A collapsible support for an antenna reflector for use in supporting spacecraft antennas is described. The support has a regid base and a number of struts which are pivoted at the base. The deployment of the struts and their final configuration for supporting the antenna are illustrated.

  1. Inflatable antenna for earth observing systems

    Science.gov (United States)

    Wang, Hong-Jian; Guan, Fu-ling; Xu, Yan; Yi, Min

    2010-09-01

    This paper describe mechanical design, dynamic analysis, and deployment demonstration of the antenna , and the photogrammetry detecting RMS of inflatable antenna surface, the possible errors results form the measurement are also analysed. Ticra's Grasp software are used to predict the inflatable antenna pattern based on the coordinates of the 460 points on the parabolic surface, the final results verified the whole design process.

  2. Adaptive Nulling in Hybrid Reflector Antennas

    Science.gov (United States)

    1992-09-01

    correction of reflector distortion and vernier beamsteering, MEEE Trans. Antennas Propagat, 36:1351-1358. 4 Cherrette , A.R., et al (1989) Compensation of...Propagat, 36:1351-1358. 4. Cherrette , A.R., et al (1989) Compensation of reflector antenna surface distortion using an array feed,IEEE Trans. Antennas

  3. Fundamentals of antennas concepts and applications

    CERN Document Server

    Christodoulou, Christos G

    2001-01-01

    This tutorial explains antenna design and application for various systems, including communications, remote sensing, radar, and biomedicine. It describes basic wire and array antennas in detail and introduces other types such as reflectors, lenses, horns, Yagi, microstrip, and frequency-independent antennas. Integration issues and technical challenges are discussed. Aimed at students, engineers, researchers, and technical professionals.

  4. Application of the SWE-to-PWE antenna diagnostics technique to an offset reflector antenna

    DEFF Research Database (Denmark)

    Cappellin, Cecilia; Frandsen, Aksel; Breinbjerg, Olav

    2008-01-01

    Electrical and mechanical errors in an antenna may seriously affect the antenna's performance. Although their presence is usually detected by anomalies in the antenna's far-field pattern, their identification is normally possible only through an analysis of the antenna's extreme near field....... The reconstruction of the extreme near field on the basis of near- or far-field measurements is thus an essential step in antenna diagnostics....

  5. The Antenna Bride and Bridegroom

    Science.gov (United States)

    2007-03-01

    ALMA Achieves Major Milestone With Antenna-Link Success The Atacama Large Millimeter/submillimeter Array (ALMA), an international telescope project, reached a major milestone on 2 March, when two 12-m ALMA prototype antennas were first linked together as an integrated system to observe an astronomical object. "This achievement results from the integration of many state-of-the-art components from Europe and North America and bodes well for the success of ALMA in Chile", said Catherine Cesarsky, ESO's Director General. ESO PR Photo 10/07 ESO PR Photo 10/07 The Prototype Antennas The milestone achievement, technically termed 'First Fringes', came at the ALMA Test Facility (ATF), located near Socorro in New Mexico. Faint radio waves emitted by the planet Saturn were collected by two ALMA prototype antennas, then processed by new, high-tech electronics to turn the two antennas into a single, high-resolution telescope system, called an interferometer. The planet's radio emissions at a frequency of 104 gigahertz were tracked by the ALMA system for more than an hour. Such pairs of antennas are the basic building blocks of the multi-antenna imaging system ALMA. In such a system, the signals recorded by each antenna are electronically combined with the signals of every other antenna to form a multitude of pairs. Each pair contributes unique information that is used to build a highly detailed image of the astronomical object under observation. When completed in the year 2012, ALMA will have 66 antennas. "Our congratulations go to the dedicated team of scientists, engineers and technicians who produced this groundbreaking achievement for ALMA. Much hard work and many long hours went into this effort, and we appreciate it all. This team should be very proud today," said NRAO Director Fred K.Y. Lo. "With this milestone behind us, we now can proceed with increased confidence toward completing ALMA," he added. ALMA, located at an elevation of 5,000m in the Atacama Desert of

  6. Photogrammetry Of A Parabolic Antenna

    Science.gov (United States)

    Merrick, W. D.; Lansing, F. L.; Stoller, F. W.; Lobb, V. B.

    1988-01-01

    Surface measured with accuracy better than 10 to the negative fifth power times diameter. Report describes use of advanced close-range photogrammetry to determine deviations of 34-m-diameter antenna main reflector and subreflector from nominal paraboloidal shapes. Measurements enable removal of linear offsets and angular misalignments of subreflector, with consequent increase of 4 percent in aperture efficiency.

  7. Tunable Antennas for Mobile Devices

    DEFF Research Database (Denmark)

    Morris, Art; Barrio, Samantha Caporal Del; Shin, J

    2014-01-01

    Modern mobile terminal design has been driven by the user interface and broadband connectivity. Real world RF performance has substantially fallen recently which impacts data rates, battery life and often causes lost connections. This has been caused by changing antenna location and reduced anten...

  8. Wireless Communication with Multiple Antennas

    Indian Academy of Sciences (India)

    2013-07-05

    Emre Telatar, “Capacity of Multi-antenna Gaussian Channels,” European. Transactions on Telecommunications, vol.10, No.6, pp.585-595, 1999. Similar diminishing-return behaviour with M fixed. B. Sundar Rajan (ECE). IASc Talk ...

  9. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed...

  10. Electro-optic detection of subwavelength terahertz spot sizes in the near field of a metal tip

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Planken, P.C.M.

    2002-01-01

    We report on a method to obtain a subwavelength resolution in terahertz time-domain imaging. In our method, a sharp copper tip is used to locally distort and concentrate the THz electric field. The distorted electric field, present mainly in the near field of the tip, is electro-optically measured

  11. 80-nm-tunable high-index-contrast subwavelength grating long-wavelength VCSEL: Proposal and numerical simulations

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Sirbu, Alexei

    2010-01-01

    A widely-tunable single-mode long wavelength vertical-cavity surface-emitting laser structure employing a MEMStunable high-index-contrast subwavelength grating (HCG) is suggested and numerically investigated. A very large 80- nm linear tuning range was obtained as the HCG was actuated by -220 to ...

  12. Theory of the JET ICRH antenna

    International Nuclear Information System (INIS)

    Theilhaber, K.

    1984-01-01

    The JET antenna has been conceived as a 'limiter antenna', completely recessed in a lateral frame which has the dual purpose of protecting the conductors and limiting the plasma radius. The coupling of this antenna is calculated in slab geometry, using a variational formulation which finds the self-consistent currents in the antenna elements. Full account is taken of the modes excited inside the limiter frame and of their coupling to waves in the inhomogeneous plasma. This yields the antenna impedance as a function of frequency and the field structure inside the plasma, including power fluxes and dispersion, as a function of penetration. (author)

  13. Microstrip Antenna Design for Femtocell Coverage Optimization

    Directory of Open Access Journals (Sweden)

    Afaz Uddin Ahmed

    2014-01-01

    Full Text Available A mircostrip antenna is designed for multielement antenna coverage optimization in femtocell network. Interference is the foremost concern for the cellular operator in vast commercial deployments of femtocell. Many techniques in physical, data link and network-layer are analysed and developed to settle down the interference issues. A multielement technique with self-configuration features is analyzed here for coverage optimization of femtocell. It also focuses on the execution of microstrip antenna for multielement configuration. The antenna is designed for LTE Band 7 by using standard FR4 dielectric substrate. The performance of the proposed antenna in the femtocell application is discussed along with results.

  14. Forward Scattering of Loaded and Unloaded Antennas

    DEFF Research Database (Denmark)

    Gustafsson, Mats; Andersen, Jørgen Bach; Kristensson, Gerhard

    2012-01-01

    Forward scattering of antennas is related to antenna performance via the forward-scattering sum rule. The forward-scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizability...... of the antenna structure. Here, the forward-scattering sum rule is experimentally verified for loaded, short-circuit, and open-circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas...... with a symmetric radiation pattern in the forward and backward directions....

  15. Multi-antenna synthetic aperture radar

    CERN Document Server

    Wang, Wen-Qin

    2013-01-01

    Synthetic aperture radar (SAR) is a well-known remote sensing technique, but conventional single-antenna SAR is inherently limited by the minimum antenna area constraint. Although there are still technical issues to overcome, multi-antenna SAR offers many benefits, from improved system gain to increased degrees-of-freedom and system flexibility. Multi-Antenna Synthetic Aperture Radar explores the potential and challenges of using multi-antenna SAR in microwave remote sensing applications. These applications include high-resolution imaging, wide-swath remote sensing, ground moving target indica

  16. Miniaturized Planar Split-Ring Resonator Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    on how small this antenna can be. In practice, the lower bound is set by losses in utilized materials and manufacturing inaccuracies. As an example, an antenna of ka=0.09 was designed, fabricated and tested. Although the initially fabricated antenna prototype had the input impedance of 43 ohms......, it was subsequently tuned to 50 ohms simply by cutting out the excessive arm length. This tuning technique is especially useful in practical applications, since it allows the antenna to be tuned in-place and thereby compensate for various inaccuracies as well as for an antenna environment....

  17. COMWIN Antenna System Fiscal Year 2000 Report

    National Research Council Canada - National Science Library

    Adams, R

    2000-01-01

    .... The Joint Tactical Radio (JTR) requires this frequency. The figure of merit to determine whether the radio is efficient in the band is a Standing Wave Ratio (VSWR) of less than 3:1. The COMWIN antenna system would consist of three antennas. The first antenna, in the form of a vest, would operate in the 30- to 500-MHz band. The helmet antenna would operate in the 500- to 2000 MHz band. An antenna that runs down the edges would operate in the 2- to 30-MHz band.

  18. Measurement of Antenna Bore-Sight Gain

    Science.gov (United States)

    Fortinberry, Jarrod; Shumpert, Thomas H.

    2016-01-01

    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  19. Benchmark simulations of ICRF antenna coupling

    International Nuclear Information System (INIS)

    Louche, F.; Lamalle, P. U.; Messiaen, A. M.; Compernolle, B. van; Milanesio, D.; Maggiora, R.

    2007-01-01

    The paper reports on ongoing benchmark numerical simulations of antenna input impedance parameters in the ion cyclotron range of frequencies with different coupling codes: CST Microwave Studio, TOPICA and ANTITER 2. In particular we study the validity of the approximation of a magnetized plasma slab by a dielectric medium of suitably chosen permittivity. Different antenna models are considered: a single-strap antenna, a 4-strap antenna and the 24-strap ITER antenna array. Whilst the diagonal impedances are mostly in good agreement, some differences between the mutual terms predicted by Microwave Studio and TOPICA have yet to be resolved

  20. Design of broadband single polarized antenna

    Science.gov (United States)

    Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

    2015-05-01

    In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

  1. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  2. SKB - PNC. Development of tunnel radar antennas

    International Nuclear Information System (INIS)

    Falk, L.

    1991-07-01

    Tunnel antennas for the RAMAC borehole radar system have been developed and tested in the field. The antennas are of the loaded dipole type and the receiver and transmitter electronics have been rebuilt to screen them from the antennas. A series of measurements has demonstrated that the radar pulse is short and well shaped and relatively free from ringing, even compared with the existing borehole antennas. Two antenna sets were tested: one centered at 60 MHz and another above 100 MHz. Both produced excellent radar pictures when tested in tunnels in Stripa mine. The antennas have been designed to be easy to carry, since the signal quality often depends on the way the antenna is held relative to electric conductors in the tunnels. (au) (46 figs., 57 refs.)

  3. Improvement of antenna decoupling in radar systems

    Science.gov (United States)

    Anchidin, Liliana; Topor, Raluca; Tamas, Razvan D.; Dumitrascu, Ana; Danisor, Alin; Berescu, Serban

    2015-02-01

    In this paper we present a type of antipodal Vivaldi antenna design, which can be used for pulse radiation in UWB communication. The Vivaldi antenna is a special tapered slot antenna with planar structure which is easily to be integrated with transmitting elements and receiving elements to form a compact structure. When the permittivity is very large, the wavelength of slot mode is so short that the electromagnetic fields concentrate in the slot to form an effective and balanced transmission line. Due to its simple structure and small size the Vivaldi antennas are one of the most popular designs used in UWB applications. However, for a two-antenna radar system, there is a high mutual coupling between two such antennas due to open configuration. In this paper, we propose a new method for reducing this effect. The method was validated by simulating a system of two Vivaldi antennas in front of a standard target.

  4. Anomalous transmission through heavily doped conducting polymer films with periodic subwavelength hole array

    Science.gov (United States)

    Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

    2006-08-01

    We observed resonantly enhanced (or anomalous transmission) terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF 6 molecules [PPy(PF6)]. The anomalous transmission spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the resonantly enhanced transmission peaks are broader in the exotic metallic PPy(PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, indicating that the surface plasmon polaritons on the PPy(PF6) film surfaces have higher attenuation.

  5. Graphene coated subwavelength wires: a theoretical investigation of emission and radiation properties

    International Nuclear Information System (INIS)

    Cuevas, Mauro

    2017-01-01

    Highlights: • Decay rate in a dielectric graphene coated wire. • Localized surface plasmons. • Excitation of multipolar resonances. - Abstract: This work analyzes the emission and radiation properties of a single optical emitter embedded in a graphene–coated subwavelength wire. We discuss the modifications of the spontaneous emission rate and the radiation efficiency as a function of the position and orientation of the dipole inside the wire. Our results show that these quantities can be enhanced by several orders of magnitude when the emission frequency coincides with one of the resonance frequencies of the graphene–coated wire. In particular, high–order plasmon resonances are excited when the emitter is moved from the wire center. Modifications resulting from varying the orientation of the dipole in the near field distribution and in the far field intensities are shown.

  6. Mechanism of optical unidirectional transmission in subwavelength dual-metal gratings

    Science.gov (United States)

    Gao, H.; Zheng, Z. Y.; Hao, H. Y.; Dong, A. G.; Fan, Z. J.; Liu, D. H.

    2014-03-01

    The mechanism of optical unidirectional (OUD) transmission in parallel subwavelength dual-metal gratings was investigated. It was found that this kind of OUD phenomenon originates from the coupling of the surface plasmon polaritons (SPPs) between the front grating and a layer of metal film which replaces the rear grating. The higher the intensity of the coupled SPPs at the entrances of the rear grating, the higher the transmittance can be achieved. Basing on this property, an effective OUD example was achieved by exploring the intensity difference at the entrances of the rear gratings between the two incidences of opposite directions. In this kind of OUD, the positive transmittance can exceed 80 % and the difference between the transmittances of the two opposite directions can be as large as 63 %. The detailed design process was also presented.

  7. Theoretical Investigation of Subwavelength Gratings and Vertical Cavity Lasers Employing Grating Structures

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza

    This thesis deals with theoretical investigations of a newly proposed grating structure, referred to as hybrid grating (HG) as well as vertical cavity lasers based on the grating reflectors. The HG consists of a near-subwavelength grating layer and an unpatterned high-refractive-index cap layer...... directions, which is analogous to electronic quantum wells in conduction or valence bands. Several interesting configurations of heterostructures have been investigated and their potential in fundamental physics study and applications are discussed. For numerical and theoretical studies, a three...... feasibility than the HCG-based ones. Furthermore, the concept of cavity dispersion in vertical cavities is introduced and its importance in the modal properties is numerically investigated. The dispersion curvature of a cavity mode is interpreted as the effective photon mass of the cavity mode. In a vertical...

  8. Exploiting evanescent-wave amplification for subwavelength low-contrast particle detection

    Science.gov (United States)

    Roy, S.; Pereira, S. F.; Urbach, H. P.; Wei, Xukang; El Gawhary, O.

    2017-07-01

    The classical problem of subwavelength particle detection on a flat surface is especially challenging when the refractive index of the particle is close to that of the substrate. We demonstrate a method to improve the detection ability several times for such a situation, by enhancing the "forbidden" evanescent waves in the substrate using the principle of super-resolution with evanescent waves amplification. The working mechanism of the system and experimental validation from a design with a thin single dielectric layer is presented. The resulting system is a simple but complete example of evanescent-wave generation, amplification, and the consequent modulation of the far field. This principle can have far reaching impact in the field of particle detection in several applications ranging from contamination control to interferometric scattering microscopy for biological samples.

  9. Ultradense, Deep Subwavelength Nanowire Array Photovoltaics As Engineered Optical Thin Films

    KAUST Repository

    Tham, Douglas

    2010-11-10

    A photovoltaic device comprised of an array of 20 nm wide, 32 nm pitch array of silicon nanowires is modeled as an optical material. The nanowire array (NWA) has characteristic device features that are deep in the subwavelength regime for light, which permits a number of simplifying approximations. Using photocurrent measurements as a probe of the absorptance, we show that the NWA optical properties can be accurately modeled with rigorous coupled-wave analysis. The densely structured NWAs behave as homogeneous birefringent materials into the ultraviolet with effective optical properties that are accurately modeled using the dielectric functions of bulk Si and SiO 2, coupled with a physical model for the NWA derived from ellipsometry and transmission electron microscopy. © 2010 American Chemical Society.

  10. Controllable synthesis of periodic flower-like ZnO nanostructures on Si subwavelength grating structures

    International Nuclear Information System (INIS)

    Ko, Yeong Hwan; Leem, Jung Woo; Yu, Jae Su

    2011-01-01

    We report on the periodic well-defined flower-like zinc oxide (ZnO) nanostructures (NSs) self-assembled through a simple hydrothermal method using silicon (Si) subwavelength grating (SWG) structures. The Si SWGs serve as building blocks for constructing a two-dimensional (2D) periodic architecture to integrate the one-dimensional (1D) ZnO NSs. Various controlled morphologies of ZnO NSs with high crystallinity are obtained by changing the growth conditions. For 1D ZnO NSs integrated on periodic hexagonal Si SWG structures, the reflection characteristics are investigated in comparison with the conventional ZnO nanorod (NR) arrays. For a three-dimensional (3D) flower-like ZnO NS on Si SWGs, a relatively low total reflectance of < 8% at wavelengths of 300-1050 nm is achieved compared to the ZnO NRs on Si substrate.

  11. Self-assembly of subwavelength nanostructures with symmetry breaking in solution

    Science.gov (United States)

    Tian, Xiang-Dong; Chen, Shu; Zhang, Yue-Jiao; Dong, Jin-Chao; Panneerselvam, Rajapandiyan; Zhang, Yun; Yang, Zhi-Lin; Li, Jian-Feng; Tian, Zhong-Qun

    2016-01-01

    Nanostructures with symmetry breaking can allow the coupling between dark and bright plasmon modes to induce strong Fano resonance. However, it is still a daunting challenge to prepare bottom-up self-assembled subwavelength asymmetric nanostructures with appropriate gaps between the nanostructures especially below 5 nm in solution. Here we present a viable self-assembly method to prepare symmetry-breaking nanostructures consisting of Ag nanocubes and Au nanospheres both with tunable size (90-250 nm for Au nanospheres; 100-160 nm for Ag nanocubes) and meanwhile control the nanogaps through ultrathin silica shells of 1-5 nm thickness. The Raman tag of 4-mercaptobenzoic acid (MBA) assists the self-assembly process and endows the subwavelength asymmetric nanostructures with surface-enhanced Raman scattering (SERS) activity. Moreover, thick silica shells (above 50 nm thickness) can be coated on the self-assembled nanostructures in situ to stabilize the whole nanostructures, paving the way toward bioapplications. Single particle scattering spectroscopy with a 360° polarization resolution is performed on individual Ag nanocube and Au nanosphere dimers, correlated with high-resolution TEM characterization. The asymmetric dimers exhibit strong configuration and polarization dependence Fano resonance properties. Overall, the solution-based self-assembly method reported here is opening up new opportunities to prepare diverse multicomponent nanomaterials with optimal performance.Nanostructures with symmetry breaking can allow the coupling between dark and bright plasmon modes to induce strong Fano resonance. However, it is still a daunting challenge to prepare bottom-up self-assembled subwavelength asymmetric nanostructures with appropriate gaps between the nanostructures especially below 5 nm in solution. Here we present a viable self-assembly method to prepare symmetry-breaking nanostructures consisting of Ag nanocubes and Au nanospheres both with tunable size (90-250 nm

  12. Achieving selective interrogation and sub-wavelength resolution in thin plates with embedded metamaterial acoustic lenses

    Energy Technology Data Exchange (ETDEWEB)

    Semperlotti, F., E-mail: fsemperl@nd.edu; Zhu, H. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2014-08-07

    In this study, we present an approach to ultrasonic beam-forming and high resolution identification of acoustic sources having critical implications for applications such as structural health monitoring. The proposed concept is based on the design of dynamically tailored structural elements via embedded acoustic metamaterial lenses. This approach provides a completely new alternative to conventional phased-array technology enabling the formation of steerable and collimated (or focused) ultrasonic beams by exploiting a single transducer. Numerical results show that the ultrasonic beam can be steered by simply tuning the frequency of the excitation. Also, the embedded lens can be designed to achieve sub-wavelength resolution to clustered acoustic sources, which is a typical scenario encountered in incipient structural damage.

  13. Dual-function beam splitter of a subwavelength fused-silica grating.

    Science.gov (United States)

    Feng, Jijun; Zhou, Changhe; Zheng, Jiangjun; Cao, Hongchao; Lv, Peng

    2009-05-10

    We present the design and fabrication of a novel dual-function subwavelength fused-silica grating that can be used as a polarization-selective beam splitter. For TM polarization, the grating can be used as a two-port beam splitter at a wavelength of 1550 nm with a total diffraction efficiency of 98%. For TE polarization, the grating can function as a high-efficiency grating, and the diffraction efficiency of the -1st order is 95% under Littrow mounting. This dual-function grating design is based on a simplified modal method. By using the rigorous coupled-wave analysis, the optimum grating parameters can be determined. Holographic recording technology and inductively coupled plasma etching are used to manufacture the fused-silica grating. Experimental results are in agreement with the theoretical values.

  14. All-Si photodetector for telecommunication wavelength based on subwavelength grating structure and critical coupling

    Directory of Open Access Journals (Sweden)

    Alireza Taghizadeh

    2017-09-01

    Full Text Available We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered subwavelength grating structure topped with a silicide layer of nanometers thickness as an absorbing material. It is shown that a nearly-perfect light absorption is possible for the thin silicide layer by its integration to the grating resonator. The absorption is shown to be maximized when the critical coupling condition is satisfied. Simulations show that the external quantum efficiency of the proposed photodetector with a 2-nm-thick PtSi absorbing layer at the center wavelength of 1550 nm can reach up to ∼60%.

  15. Subwavelength grating enabled on-chip ultra-compact optical true time delay line.

    Science.gov (United States)

    Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R

    2016-07-26

    An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth.

  16. Functional metasurfaces based on metallic and dielectric subwavelength slits and stripes array

    Science.gov (United States)

    Guo, Yinghui; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Gao, Ping; Wang, Yanqin; Luo, Xiangang

    2018-04-01

    Starting with the early works of extraordinary optical transmission and extraordinary Young’s interference, researchers have been fascinated by the unusual optical properties displayed by metallic holes/slits and subsequently found similar abnormities in dielectric counterparts. Benefiting from the shrinking wavelength of surface plasmon polaritons excited in metallic slits and high refractive index of dielectric stripes, one can realize local phase modulation and approach desired dispersion by engineering the geometries of a slits and stripes array. In this review, we review recent developments in functional metasurfaces composed of various metallic and dielectric subwavelength slits and stripes arrays, with special emphasis on achromatic, ultra-broadband, quasi-continuous, multifunctional and reconfigurable metasurfaces. Particular attention is paid to provide insight into the design strategies for these devices. Finally, we give an outlook of the development in this fascinating area.

  17. Simulation of polarization-dependent film with subwavelength nano-hole array

    Science.gov (United States)

    Yu, Yue; Wei, Dong; Long, Huabao; Xin, Zhaowei; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

    2018-02-01

    When lightwave passes through a metal thin film with a periodic subwavelength hole arrays structure, its transmittance is significantly improved in the partial band compared to other wavelength. Changing the size of the hole, the period or metal material, will make the transmission curve different. Here, we add a layer of dielectric material on the surface of the metal film, such as liquid crystal(LC), by controlling voltage on LC to change the refractive index of this layer, then we can change the transmission curve, and achieve using voltage to move the transmission curve. When there is need for polarization, the holes can be made of a rectangle whose length and width are different or other shapes, for different polarization state of the light, and the film will display different transmission characteristics.

  18. Subwavelength Microstructures Fabrication by Self-Organization Processes in Photopolymerizable Nanocomposite

    Directory of Open Access Journals (Sweden)

    I. Yu. Denisyuk

    2012-01-01

    Full Text Available This paper describes our research results on nanometers sizes subwavelength nanostructure fabrication by UV curing of special nanocomposite material with self-organization and light self-focusing effects. For this purpose, special UV curable nanocomposite material with a set of effects was developing: light self-focusing in the photopolymer with positive refractive index change, self-organization based on photo-induced nanoparticles transportation, and oxygen-based polymerization threshold. Both holographic and projection lithography writing methods application for microstructure making shows geometrical optical laws perturbation as result of nanocomposite self-organization effects with formation of nanometers-sized high-aspect-ratio structures. Obtained results will be useful for diffraction limit overcoming in projection lithography as well as for deep lithography technique.

  19. Dielectric-based subwavelength metallic meanders for wide-angle band absorbers.

    Science.gov (United States)

    Shen, Su; Qiao, Wen; Ye, Yan; Zhou, Yun; Chen, Linsen

    2015-01-26

    We propose nano-meanders that can achieve wide-angle band absorption in visible regime. The nano-meander consists of a subwavelength dielectric grating covered by continuous ultra-thin Aluminum film (less than one tenth of the incident wavelength). The excited photonic resonant modes, such as cavity mode, surface plasmonic mode and Rayleigh-Wood anomaly, are discussed in detail. Nearly total resonant absorption due to funneling mechanism in the air nano-groove is almost invariant with large incident angle in transverse magnetic polarization. From both the structural geometry and the nanofabrication point of view, the light absorber has a very simple geometrical structure and it is easy to be integrated into complex photonic devices. The highly efficient angle-robust light absorber can be potential candidate for a range of passive and active photonic applications, including solar-energy harvesting as well as producing artificial colors on a large scale substrate.

  20. Theoretical and numerical investigations of sub-wavelength diffractive optical structures

    DEFF Research Database (Denmark)

    Dridi, Kim

    2000-01-01

    The work in this thesis concerns theoretical and numerical investigations of sub-wavelength diffractive optical structures, relying on advanced two-dimensional vectorial numerical models that have applications in Optics and Electromagnetics. Integrated Optics is predicted to play a major role......, such as in dielectric waveguides with gratings and periodic media or photonic crystal structures. The vectorial electromagnetic nature of light is therefore taken into account in the modeling of these diffractive structures. An electromagnetic vector-field model for optical components design based on the classical...... finite-difference time domain method and exact radiation integrals is implemented for the polarization where the electric field vector is perpendicular to the two dimentional plane of symmetry. The computational model solves the full vectorial time domain Maxwell equations with general sources...

  1. Linear Optical and SERS Study on Metallic Membranes with Subwavelength Complementary Patterns

    Science.gov (United States)

    Hao, Qingzhen; Zeng, Yong; Jensen, Lasse; Werner, Douglas; Crespi, Vincent; Huang, Tony Jun; Interdepartmental Collaboration

    2011-03-01

    An efficient technique is developed to fabricate optically thin metallic films with subwavelength patterns and their complements simultaneously. By comparing the spectra of the complementary films, we show that Babinet's principle nearly holds in the optical domain. A discrete-dipole approximation can qualitatively describe their spectral dependence on the geometry of the constituent particles and the illuminating polarization. Using pyridine as probe molecules, we studied surface-enhanced Raman spectroscopy (SERS) from the complementary structure. Although the complementary structure posses closely related linear spectra, they have quite different near-field behaviors. For hole arrays, their averaged local field gains as well as the SERS enhancements are strongly correlated to their transmission spectra. We therefore can use cos 4 θ to approximately describe the dependence of the Raman intensity on the excitation polarization angle θ , while the complementary particle arrays present maximal local field gains at wavelengths generally much bigger than their localized surface plasmonic resonant wavelengths.

  2. Focused-ion beam patterning of organolead trihalide perovskite for subwavelength grating nanophotonic applications

    KAUST Repository

    Alias, Mohd Sharizal

    2015-07-30

    The coherent amplified spontaneous emission and high photoluminescence quantum efficiency of organolead trihalide perovskite have led to research interest in this material for use in photonic devices. In this paper, the authors present a focused-ion beam patterning strategy for methylammonium lead tribromide (MAPbBr3) perovskite crystal for subwavelength grating nanophotonic applications. The essential parameters for milling, such as the number of scan passes, dwell time, ion dose, ion current, ion incident angle, and gas-assisted etching, were experimentally evaluated to determine the sputtering yield of the perovskite. Based on our patterning conditions, the authors observed that the sputtering yield ranged from 0.0302 to 0.0719 μm3/pC for the MAPbBr3 perovskite crystal. Using XeF2 for the focused-ion beam gas-assisted etching, the authors determined that the etching rate was reduced to between 0.40 and 0.97, depending on the ion dose, compared with milling with ions only. Using the optimized patterning parameters, the authors patterned binary and circular subwavelength grating reflectors on the MAPbBr3 perovskite crystal using the focused-ion beam technique. Based on the computed grating structure with around 97% reflectivity, all of the grating dimensions (period, duty cycle, and grating thickness) were patterned with nanoscale precision (>±3 nm), high contrast, and excellent uniformity. Our results provide a platform for utilizing the focused-ion beam technique for fast prototyping of photonic nanostructures or nanodevices on organolead trihalide perovskite.

  3. Optically resonant subwavelength films for tamper-indicating tags and seals

    Science.gov (United States)

    Alvine, Kyle J.; Suter, Jonathan D.; Bernacki, Bruce E.; Bennett, Wendy D.

    2015-05-01

    We present the design, modeling and performance of a proof-of-concept tamper indicating approach that exploits newlydeveloped subwavelength-patterned films. These films have a nanostructure-dependent resonant optical reflection that is wavelength, angle, and polarization dependent. As such, they can be tailored to fabricate overlay transparent films for tamper indication and authentication of sensitive or controlled materials not possible with currently-known technologies. An additional advantage is that the unique optical signature is dictated by the geometry and fabrication process of the nanostructures in the film, rather than on the material used. The essential structure unit in the subwavelength resonant coating is a nanoscale Open-Ring Resonator (ORR). This building block is fabricated by coating a dielectric nanoscale template with metal to form a hemispherical shell-like structure. This curved metallic shell structure has a cross-section with an intrinsic capacitance and inductance and is thus the optical equivalent to the well-known "LC" circuit where the capacitance and inductance are determined by the nanoshell dimensions. For structures with sub 100 nm scale, this resonance occurs in the visible electromagnetic spectrum, and in the IR for larger shells. Tampering of the film would be visible though misalignment of the angle-sensitive features in the film. It is additionally possible to add in intrinsic oxidation and strain sensitive matrix materials to further complicate tamper repair and counterfeiting. Cursory standoff readout would be relatively simple using a combination of a near-infrared (or visible) LED flashlight and polarizer or passively using room lighting illumination and a dispersive detector.

  4. Antenna Arrays and Automotive Applications

    CERN Document Server

    Rabinovich, Victor

    2013-01-01

    This book throws a lifeline to designers wading through mounds of antenna array patents looking for the most suitable systems for their projects. Drastically reducing the research time required to locate solutions to the latest challenges in automotive communications, it sorts and systematizes material on cutting-edge antenna arrays that feature multi-element communication systems with enormous potential for the automotive industry. These new systems promise to make driving safer and more efficient, opening up myriad applications, including vehicle-to-vehicle traffic that prevents collisions, automatic toll collection, vehicle location and fine-tuning for cruise control systems. This book’s exhaustive coverage begins with currently deployed systems, frequency ranges and key parameters. It proceeds to examine system geometry, analog and digital beam steering technology (including "smart" beams formed in noisy environments), maximizing signal-to-noise ratios, miniaturization, and base station technology that ...

  5. Broadband Cylindrical Antenna and Method

    Science.gov (United States)

    2016-07-27

    May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is...Slotted cylinder antennas have been proposed in submarine applications before. For example, in U.S. Patent No. 6,127,983, Rivera and Josypenko disclose

  6. Miniaturization of Spherical Magnetodielectric Antennas

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle

    ; Arbitrary order of the spherical wave, arbitrary radius of the spherical antenna, as well as arbitrarily large core permeability and/or permittivity, given an inversely proportional frequency variation of the imaginary part(s) and an arbitrary dispersion of the real part(s) - thus describing both lossless...... with a magnetic loss tangent of 1 and relative permeability of 300 yield Q/e equal 65% of the Chu lower bound, with a simultaneous e of 71%....

  7. Hybrid Maritime Satellite Communication Antenna

    DEFF Research Database (Denmark)

    Smith, Thomas Gunst

    Hybrid antennas for a maritime satellite communication terminal with simultaneous operation at L- and Ka-band have been investigated. The frequency bands of interest are 1; 525:0 1; 660:5 MHz (RX+TX, RHCP), 19:7 20:2 (RX, LHCP) and 29:5 30:0 GHz (TX, RHCP), which are all part of the Inmarsat BGAN...

  8. Band-notched spiral antenna

    Science.gov (United States)

    Jeon, Jae; Chang, John

    2018-03-13

    A band-notched spiral antenna having one or more spiral arms extending from a radially inner end to a radially outer end for transmitting or receiving electromagnetic radiation over a frequency range, and one or more resonance structures positioned adjacent one or more segments of the spiral arm associated with a notch frequency band or bands of the frequency range so as to resonate and suppress the transmission or reception of electromagnetic radiation over said notch frequency band or bands.

  9. Layout Of Antennas And Cables In A Large Array

    Science.gov (United States)

    Logan, Ronald T., Jr.

    1995-01-01

    Layout devised to minimize total land area occupied by large phased array of antennas and to minimize total length of cables in array. In original intended application, array expanded version of array of paraboloidal-dish microwave communication antennas of Deep Space Network. Layout also advantageous for other phased arrays of antennas and antenna elements, including notably printed-circuit microwave antenna arrays.

  10. Seismic metamaterials based on isochronous mechanical oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Finocchio, G., E-mail: gfinocchio@unime.it; Garescì, F.; Azzerboni, B. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Casablanca, O.; Chiappini, M. [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via Vigna Murata 605, 00143 Roma (Italy); Ricciardi, G. [Department of Civil, Informatic, Architectural, and Environmental Engineering and Applied Mathematics, C.da di Dio, I-98166 Messina (Italy); Alibrandi, U. [Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576 (Singapore)

    2014-05-12

    This Letter introduces a seismic metamaterial (SM) composed by a chain of mass-in-mass system able to filter the S-waves of an earthquake. We included the effect of the SM into the mono dimensional model for the soil response analysis. The SM modifies the soil behavior and in presence of an internal damping the amplitude of the soil amplification function is reduced also in a region near the resonance frequency. This SM can be realized by a continuous structure with inside a 3d-matrix of isochronous oscillators based on a sphere rolling over a cycloidal trajectory.

  11. Tunable microwave metamaterials based on ordinary water

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei V.; Jacobsen, Rasmus Elkjær; Arslanagic, Samel

    2017-01-01

    All-dielectric metamaterials are the growing trend in optics and electromagnetics. They require materials with high permittivity, for example silicon in photonics. Aiming the microwaves range we present here water as a unique substance for employing in metamaterials design. Dependence of water...

  12. Bianisotropic metamaterials based on twisted asymmetric crosses

    International Nuclear Information System (INIS)

    Reyes-Avendaño, J A; Sampedro, M P; Juárez-Ruiz, E; Pérez-Rodríguez, F

    2014-01-01

    The effective bianisotropic response of 3D periodic metal-dielectric structures, composed of crosses with asymmetrically-cut wires, is investigated within a general homogenization theory using the Fourier formalism and the form-factor division approach. It is found that the frequency dependence of the effective permittivity for a system of periodically-repeated layers of metal crosses exhibits two strong resonances, whose separation is due to the cross asymmetry. Besides, bianisotropic metamaterials, having a base of four twisted asymmetric crosses, are proposed. The designed metamaterials possess negative refractive index at frequencies determined by the cross asymmetry, the gap between the arms of adjacent crosses lying on the same plane, and the type of Bravais lattice. (papers)

  13. Antenna development for astroparticle and radioastronomy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Didier, E-mail: charrier@emn.fr [Subatech, Ecole des Mines de Nantes - CNRS/IN2P3 - Universite de Nantes (France)

    2012-01-11

    An active dipole antenna is in operation since five years at the Nancay radio Observatory (France) in the CODALEMA experiment. A new version of this active antenna has been developed, whose shape gave its name of 'Butterfly' antenna. Compared to the previous version, this new antenna has been designed to be more efficient at low frequencies, which could permit the detection of atmospheric showers at large distances. Despite a size of only 2 m Multiplication-Sign 1 m in each polarization, its sensitivity is excellent in the 30-80 MHz bandwidth. Three antennas in dual polarization were installed on the CODALEMA experiment, and four other have been recently installed on the Auger area in the scope of the AERA project. The main characteristics of the Butterfly antenna are detailed with an emphasis on its key features which make it a good candidate for the low frequency radioastronomy and the radio detection of transients induced by high energy cosmic rays.

  14. Millimeter-wave antennas configurations and applications

    CERN Document Server

    du Preez, Jaco

    2016-01-01

    This book comprehensively reviews the state of the art in millimeter-wave antennas, traces important recent developments and provides information on a wide range of antenna configurations and applications. While fundamental theoretical aspects are discussed whenever necessary, the book primarily focuses on design principles and concepts, manufacture, measurement techniques, and practical results. Each of the various antenna types scalable to millimeter-wave dimensions is considered individually, with coverage of leaky-wave and surface-wave antennas, printed antennas, integrated antennas, and reflector and lens systems. The final two chapters address the subject from a systems perspective, providing an overview of supporting circuitry and examining in detail diverse millimeter-wave applications, including high-speed wireless communications, radio astronomy, and radar. The vast amount of information now available on millimeter-wave systems can be daunting for researchers and designers entering the field. This b...

  15. A Review of Antennas for Picosatellite Applications

    Directory of Open Access Journals (Sweden)

    Abdul Halim Lokman

    2017-01-01

    Full Text Available Cube Satellite (CubeSat technology is an attractive emerging alternative to conventional satellites in radio astronomy, earth observation, weather forecasting, space research, and communications. Its size, however, poses a more challenging restriction on the circuitry and components as they are expected to be closely spaced and very power efficient. One of the main components that will require careful design for CubeSats is their antennas, as they are needed to be lightweight, small in size, and compact or deployable for larger antennas. This paper presents a review of antennas suitable for picosatellite applications. An overview of the applications of picosatellites will first be explained, prior to a discussion on their antenna requirements. Material and antenna topologies which have been used will be subsequently discussed prior to the presentation of several deployable configurations. Finally, a perspective and future research work on CubeSat antennas will be discussed in the conclusion.

  16. Metamaterial Embedded Wearable Rectangular Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    J. G. Joshi

    2012-01-01

    Full Text Available This paper presents an indigenous low-cost metamaterial embedded wearable rectangular microstrip patch antenna using polyester substrate for IEEE 802.11a WLAN applications. The proposed antenna resonates at 5.10 GHz with a bandwidth and gain of 97 MHz and 4.92 dBi, respectively. The electrical size of this antenna is 0.254λ×0.5λ. The slots are cut in rectangular patch to reduce the bending effect. This leads to mismatch the impedance at WLAN frequency band; hence, a metamaterial square SRR is embedded inside the slot. A prototype antenna has been fabricated and tested, and the measured results are presented in this paper. The simulated and measured results of the proposed antenna are found to be in good agreement. The bending effect on the performance of this antenna is experimentally verified.

  17. Spherical near-field antenna measurements — The most accurate antenna measurement technique

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2016-01-01

    The spherical near-field antenna measurement technique combines several advantages and generally constitutes the most accurate technique for experimental characterization of radiation from antennas. This paper/presentation discusses these advantages, briefly reviews the early history and present...

  18. An Approach for Smart Antenna Testbed

    Science.gov (United States)

    Kawitkar, R. S.; Wakde, D. G.

    2003-07-01

    The use of wireless, mobile, personal communications services are expanding rapidly. Adaptive or "Smart" antenna arrays can increase channel capacity through spatial division. Adaptive antennas can also track mobile users, improving both signal range and quality. For these reasons, smart antenna systems have attracted widespread interest in the telecommunications industry for applications to third generation wireless systems.This paper aims to design and develop an advanced antennas testbed to serve as a common reference for testing adaptive antenna arrays and signal combining algorithms, as well as complete systems. A flexible suite of off line processing software should be written using matlab to perform system calibration, test bed initialization, data acquisition control, data storage/transfer, off line signal processing and analysis and graph plotting. The goal of this paper is to develop low complexity smart antenna structures for 3G systems. The emphasis will be laid on ease of implementation in a multichannel / multi-user environment. A smart antenna test bed will be developed, and various state-of-the-art DSP structures and algorithms will be investigated.Facing the soaring demand for mobile communications, the use of smart antenna arrays in mobile communications systems to exploit spatial diversity to further improve spectral efficiency has recently received considerable attention. Basically, a smart antenna array comprises a number of antenna elements combined via a beamforming network (amplitude and phase control network). Some of the benefits that can be achieved by using SAS (Smart Antenna System) include lower mobile terminal power consumption, range extension, ISI reduction, higher data rate support, and ease of integration into the existing base station system. In terms of economic benefits, adaptive antenna systems employed at base station, though increases the per base station cost, can increase coverage area of each cell site, thereby reducing

  19. VAlidation STandard antennas: Past, present and future

    DEFF Research Database (Denmark)

    Drioli, Luca Salghetti; Ostergaard, A; Paquay, M

    2011-01-01

    designed for validation campaigns of antenna measurement ranges. The driving requirements of VAST antennas are their mechanical stability over a given operational temperature range and with respect to any orientation of the gravity field. The mechanical design shall ensure extremely stable electrical....../V-band of telecom satellites. The paper will address requirements for future VASTs and possible architecture for multi-frequency Validation Standard antennas....

  20. International Mapping of Antenna-Measurement Facilities

    DEFF Research Database (Denmark)

    Boccia, Luigi; Breinbjerg, Olav; Di Massa, Giuseppe

    2006-01-01

    This paper presents a comprehensive international mapping of antenna-measurement facilities. This initiative, conducted within the framework of the Antenna Centre of Excellence (ACE) of the European Union, is oriented toward all institutions having research, development, or operational activities...... measurements, in particular from the wireless communication industry, to identify and contact antenna-measurement facilities. The first phase of the mapping showed a significant and encouraging reaction to this initiative, with more than 50 European facilities currently registered. The next phase aims...

  1. Porous textile antenna designs for improved wearability

    Science.gov (United States)

    Shahariar, Hasan; Soewardiman, Henry; Muchler, Clifford A.; Adams, Jacob J.; Jur, Jesse S.

    2018-04-01

    Textile antennas are an integral part of the next generation personalized wearable electronics system. However, the durability of textile antennas are rarely discussed in the literature. Typical textile antennas are prone to damage during normal wearable user scenarios, washing, and heat cycling over time. Fabricating a durable, washable, flexible, and breathable (like textile materials) antenna is challenging due to the incompatibility of the mechanical properties of conductive materials and soft textile materials. This paper describes a scalable screen printing process on an engineered nonwoven substrate to fabricate microstrip patch antennas with enhanced durability. This work used an Evolon® nonwoven substrate with low surface roughness (˜Ra = 18 μm) and high surface area (˜2.05 mm2 mm-2 of fabric area) compared to traditional textile materials, which allows the ink to penetrate evenly in the fiber bulk with its strong capillary wicking force and enhances print resolution. The composite layer of ink and fiber is conductive and enables the antennas to maintain high mechanical flexibility without varying its RF (Radio Frequency) properties. Additionally, the antennas are packaged by laminating porous polyurethane web to make the device durable and washable. The fully packaged antennas maintain the structural flexibility and RF functionality after 15 cycles of washing and drying. To improve the air permeability and enhance flexibility the antenna is also modified by incorporating holes in the both patch and ground layer of the antenna. The antennas were analyzed before and after submerging in water to observe the effect of wetting and drying with respect to frequency response. The porous antenna with holes recovered 3x times faster than the one without holes (solid) from fully wet state (saturated with water) to the dry state, demonstrating its potential use as a moisture sensor system.

  2. Reconfigurable antennas radiations using plasma Faraday cage

    OpenAIRE

    Barro , Oumar Alassane; Himdi , Mohamed; Lafond , Olivier

    2015-01-01

    International audience; This letter presents a new reconfigurable plasma antenna associated with a Faraday cage. The Faraday cage is realized using a fluorescent lamp. A patch antenna with a broadside radiation pattern or a monopole antenna with an end-fire radiation pattern , operating at 2.45 GHz, is placed inside Faraday cage. The performance of the reconfigurable system is observed in terms of input reflection coefficient, gain and radiation pattern via simulation and measurement. It is s...

  3. Design of reconfigurable antennas using graph models

    CERN Document Server

    Costantine, Joseph; Christodoulou, Christos G; Christodoulou, Christos G

    2013-01-01

    This lecture discusses the use of graph models to represent reconfigurable antennas. The rise of antennas that adapt to their environment and change their operation based on the user's request hasn't been met with clear design guidelines. There is a need to propose some rules for the optimization of any reconfigurable antenna design and performance. Since reconfigurable antennas are seen as a collection of self-organizing parts, graph models can be introduced to relate each possible topology to a corresponding electromagnetic performance in terms of achieving a characteristic frequency of oper

  4. Handbook of smart antennas for RFID systems

    CERN Document Server

    2010-01-01

    The Handbook of Smart Antennas for RFID Systems is a single comprehensive reference on the smart antenna technologies applied to RFID. This book will provide a timely reference book for researchers and students in the areas of both smart antennas and RFID technologies. It is the first book to combine two of the most important wireless technologies together in one book. The handbook will feature chapters by leading experts in both academia and industry offering an in-depth description of terminologies and concepts related to smart antennas in various RFID systems applications.

  5. Thermal Loss in High-Q Antennas

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Bahramzy, Pevand; Svendsen, Simon

    2014-01-01

    Tunable antennas are very promising for future generations of mobile communications, where antennas are required to cover a wide range operating bands. This letter aims at characterizing the loss mechanism of tunable antennas. Tunable antennas typically exhibit a high Quality factor (Q), which ca...... lead to thermal loss due to the conductivity of the metal. The investigation shows that copper loss is non-negligible for high Q values. In the proposed design the copper loss is 2 dB, for a Q of 260 at 700 MHz....

  6. MILA Antenna Control Unit Replacement Project

    Science.gov (United States)

    Bresette, Jeremy

    2007-01-01

    The Air to Ground Subsystem (AGS) Antenna Control Units at the MILA Ground Network Tracking Station are at end-of-life and are being replaced. AGS consists of two antennas at MILA (Quad-Helix and Teltrac). Software was taken from the existing Subsystem Controller and modified for the Antenna Control Unit (ACU). The software is capable of receiving and sending commands to and from the ACU. Moving the azimuth clockwise, counterclockwise, moving the elevation up or down, turning servo power on and off, and inputting azimuth and elevation angles are commands that the antenna can receive.

  7. A Design of Double Broadband MIMO Antenna

    Directory of Open Access Journals (Sweden)

    Yanfeng Geng

    2015-01-01

    Full Text Available The MIMO antenna applied to LTE mobile system should be miniaturization and can work in the current communication frequency band; isolation between each antenna unit also should be good so as to reduce loss of radio wave energy and improve the antenna performance of the MIMO system. This paper puts forward the design scheme of a broadband MIMO double antenna. And the design of antenna unit and debugging and related technical measures, such as bending antenna bracket, are both presented; the integration design of high isolation of ultra broadband MIMO antenna is realized on the plate with the volume of 100 × 52 × 0.8 mm3; antenna working bands are 698 MHz~960 MHz and 1710 MHz~2700 MHz; in the whole spectrum, the 10 dB of port isolation can be basically achieved; in low frequency band, the isolation degree of antenna port can reach 12 dB.

  8. Vivaldi Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2016-12-01

    Full Text Available Energy harvesting is a future technology for capturing ambient energy from the environment to be recycled to feed low-power devices. A planar antipodal Vivaldi antenna is presented for gathering energy from GSM, WLAN, UMTS and related applications. The designed antenna has the potential to be used in energy harvesting systems. Moreover, the antenna is suitable for UWB applications, because it operates according to FCC regulations (3.1 – 10.6 GHz. The designed antenna is printed on ARLON 600 substrate and operates in frequency band from 0.810 GHz up to more than 12 GHz. Experimental results show good conformity with simulated performance.

  9. Transmission properties of a single metallic slit: from the subwavelength regime to the geometrical-optics limit.

    Science.gov (United States)

    Bravo-Abad, J; Martín-Moreno, L; García-Vidal, F J

    2004-02-01

    In this work we explore the transmission properties of a single slit in a metallic screen. We analyze the dependence of these properties on both slit width and angle of incident radiation. We study in detail the crossover between the subwavelength regime and the geometrical-optics limit. In the subwavelength regime, resonant transmission linked to the excitation of waveguide resonances is analyzed. Linewidth of these resonances and their associated electric-field intensities are controlled by just the width of the slit. More complex transmission spectra appear when the wavelength of light is comparable to the slit width. Rapid oscillations associated with the emergence of different propagating modes inside the slit are the main features appearing in this regime.

  10. A 3D printed helical antenna with integrated lens

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2015-01-01

    A novel antenna configuration comprising a helical antenna with an integrated lens is demonstrated in this work. The antenna is manufactured by a unique combination of 3D printing of plastic material (ABS) and inkjet printing of silver nano

  11. Inkjet-Printed Ultra Wide Band Fractal Antennas

    KAUST Repository

    Maza, Armando Rodriguez

    2012-01-01

    reduction, a Cantor-based fractal antenna which performs a larger bandwidth compared to previously published UWB Cantor fractal monopole antenna, and a 3D loop fractal antenna which attains miniaturization, impedance matching and multiband characteristics

  12. Development of Novel Integrated Antennas for CubeSats

    Data.gov (United States)

    National Aeronautics and Space Administration — The antenna system on a small satellite is a critical component, as a failure of the antenna can lead to mission failure. Present antenna systems are typically wire...

  13. MAcro-Electro-Mechanical Systems (MÆMS) based concept for microwave beam steering in reflectarray antennas

    Energy Technology Data Exchange (ETDEWEB)

    Momeni Hasan Abadi, Seyed Mohamad Amin, E-mail: momenihasana@wisc.edu; Booske, John H., E-mail: jhbooske@wisc.edu; Behdad, Nader, E-mail: behdad@wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

    2016-08-07

    We present a new approach to perform beam steering in reflecting type apertures such as reflectarray antennas. The proposed technique exploits macro-scale mechanical movements of parts of the structure to achieve two-dimensional microwave beam steering without using any solid-state devices or phase shifters integrated within the aperture of the antenna. The principles of operation of this microwave beam steering technique are demonstrated in an aperture occupied by ground-plane-backed, sub-wavelength capacitive patches with identical dimensions. We demonstrate that by tilting the ground plane underneath the entire patch array layer, a phase shift gradient can be created over the aperture of the reflectarray that determines the direction of the radiated beam. Changing the direction and slope of this phase shift gradient on the aperture allows for performing beam steering in two dimensions using only one control parameter (i.e., tilt vector of the ground plane). A proof-of-concept prototype of the structure operating at X-band is designed, fabricated, and experimentally characterized. Experiments demonstrate that small mechanical movements of the ground plane (in the order of 0.05λ{sub 0}) can be used to steer the beam direction in the ±10° in two dimensions. It is also demonstrated that this beam scanning range can be greatly enhanced to ±30° by applying this concept to the same structure when its ground plane is segmented.

  14. Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, R. L., E-mail: stenzel@physics.ucla.edu; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2015-07-15

    Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B{sub 0}. Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B{sub 0}. The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B{sub 0} has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental

  15. Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

    International Nuclear Information System (INIS)

    Stenzel, R. L.; Urrutia, J. M.

    2015-01-01

    Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B 0 . Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B 0 . The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B 0 has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental interest and of

  16. Experimental application of QCD antennas

    International Nuclear Information System (INIS)

    Bobrovskyi, Sergei

    2010-02-01

    A serious problem in searches for new physics at the LHC is the rejection of QCD induced multijet events. In this thesis the formalism of QCD antenna variables based on the SPHEL approximation of QCD matrix elements is applied for the rst time on experimentally reconstructed jets in order to discriminate QCD from supersymmetric processes. The new observables provide additional information with respect to traditional event shape variables. Albeit correlated with experimentally measured missing transverse energy, the variables can be used to improve the signal to background ratio. (orig.)

  17. Experimental application of QCD antennas

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovskyi, Sergei

    2010-02-15

    A serious problem in searches for new physics at the LHC is the rejection of QCD induced multijet events. In this thesis the formalism of QCD antenna variables based on the SPHEL approximation of QCD matrix elements is applied for the rst time on experimentally reconstructed jets in order to discriminate QCD from supersymmetric processes. The new observables provide additional information with respect to traditional event shape variables. Albeit correlated with experimentally measured missing transverse energy, the variables can be used to improve the signal to background ratio. (orig.)

  18. Solar energy collection by antennas

    Energy Technology Data Exchange (ETDEWEB)

    Corkish, R.; Green, M.A.; Puzzer, T. [University of New South Wales, Sydney (Australia). Centre for Advanced Silicon Photovoltaics and Photonics

    2002-12-01

    The idea of collecting solar electromagnetic radiation with antenna-rectifier (rectenna) structures was proposed three decades ago but has not yet been achieved. The idea has been promoted as having potential to achieve efficiency approaching 100% but thermodynamic considerations imply a lower limit of 85.4% for a non-frequency-selective rectenna and 86.8% for one with infinite selectivity, assuming maximal concentration in each case. This paper reviews the history and technical context of solar rectennas and discusses the major issues: thermodynamic efficiency limits, rectifier operation at optical frequencies, harmonics production and electrical noise. (author)

  19. Antenna analysis using neural networks

    Science.gov (United States)

    Smith, William T.

    1992-01-01

    Conventional computing schemes have long been used to analyze problems in electromagnetics (EM). The vast majority of EM applications require computationally intensive algorithms involving numerical integration and solutions to large systems of equations. The feasibility of using neural network computing algorithms for antenna analysis is investigated. The ultimate goal is to use a trained neural network algorithm to reduce the computational demands of existing reflector surface error compensation techniques. Neural networks are computational algorithms based on neurobiological systems. Neural nets consist of massively parallel interconnected nonlinear computational elements. They are often employed in pattern recognition and image processing problems. Recently, neural network analysis has been applied in the electromagnetics area for the design of frequency selective surfaces and beam forming networks. The backpropagation training algorithm was employed to simulate classical antenna array synthesis techniques. The Woodward-Lawson (W-L) and Dolph-Chebyshev (D-C) array pattern synthesis techniques were used to train the neural network. The inputs to the network were samples of the desired synthesis pattern. The outputs are the array element excitations required to synthesize the desired pattern. Once trained, the network is used to simulate the W-L or D-C techniques. Various sector patterns and cosecant-type patterns (27 total) generated using W-L synthesis were used to train the network. Desired pattern samples were then fed to the neural network. The outputs of the network were the simulated W-L excitations. A 20 element linear array was used. There were 41 input pattern samples with 40 output excitations (20 real parts, 20 imaginary). A comparison between the simulated and actual W-L techniques is shown for a triangular-shaped pattern. Dolph-Chebyshev is a different class of synthesis technique in that D-C is used for side lobe control as opposed to pattern

  20. Bio-inspired, subwavelength surface structures to control reflectivity, transmission, and scattering in the infrared

    Science.gov (United States)

    Lora Gonzalez, Federico

    Controlling the reflection of visible and infrared (IR) light at interfaces is extremely important to increase the power efficiency and performance of optics, electro-optical and (thermo)photovoltaic systems. The eye of the moth has evolved subwavelength protuberances that increase light transmission into the eye tissue and prevent reflection. The subwavelength protuberances effectively grade the refractive index from that of air (n=1) to that of the tissue (n=1.4), making the interface gradual, suppressing reflection. In theory, the moth-eye (ME) structures can be implemented with any material platform to achieve an antireflectance effect by scaling the pitch and size of protuberances for the wavelength range of interest. In this work, a bio-inspired, scalable and substrate-independent surface modification protocol was developed to realize broadband antireflective structures based on the moth-eye principle. Quasi-ordered ME arrays were fabricated in IR relevant materials using a colloidal lithography method to achieve highly efficient, omni-directional transmission of mid and far infrared (IR) radiation. The effect of structure height and aspect ratio on transmittance and scattering is explored, with discussion on experimental techniques and effective medium theory (EMT). The highest aspect ratio structures (AR = 9.4) achieved peak single-side transmittance of 98%, with >85% transmission for lambda = 7--30 microns. A detailed photon balance constructed by transmission, forward scattering, specular reflection and diffuse reflection measurements to quantify optical losses due to near-field effects will be discussed. In addition, angle-dependent transmission measurements showed that moth-eye structures provide superior antireflective properties compared to unstructured interfaces over a wide angular range (0--60° incidence). Finally, subwavelength ME structures are incorporated on a Si substrate to enhance the absorption of near infrared (NIR) light in PtSi films to

  1. Uniquely identifiable tamper-evident device using coupling between subwavelength gratings

    Science.gov (United States)

    Fievre, Ange Marie Patricia

    Reliability and sensitive information protection are critical aspects of integrated circuits. A novel technique using near-field evanescent wave coupling from two subwavelength gratings (SWGs), with the input laser source delivered through an optical fiber is presented for tamper evidence of electronic components. The first grating of the pair of coupled subwavelength gratings (CSWGs) was milled directly on the output facet of the silica fiber using focused ion beam (FIB) etching. The second grating was patterned using e-beam lithography and etched into a glass substrate using reactive ion etching (RIE). The slightest intrusion attempt would separate the CSWGs and eliminate near-field coupling between the gratings. Tampering, therefore, would become evident. Computer simulations guided the design for optimal operation of the security solution. The physical dimensions of the SWGs, i.e. period and thickness, were optimized, for a 650 nm illuminating wavelength. The optimal dimensions resulted in a 560 nm grating period for the first grating etched in the silica optical fiber and 420 nm for the second grating etched in borosilicate glass. The incident light beam had a half-width at half-maximum (HWHM) of at least 7 microm to allow discernible higher transmission orders, and a HWHM of 28 microm for minimum noise. The minimum number of individual grating lines present on the optical fiber facet was identified as 15 lines. Grating rotation due to the cylindrical geometry of the fiber resulted in a rotation of the far-field pattern, corresponding to the rotation angle of moire fringes. With the goal of later adding authentication to tamper evidence, the concept of CSWGs signature was also modeled by introducing random and planned variations in the glass grating. The fiber was placed on a stage supported by a nanomanipulator, which permitted three-dimensional displacement while maintaining the fiber tip normal to the surface of the glass substrate. A 650 nm diode laser was

  2. Determination of antenna factors using a three-antenna method at open-field test site

    Science.gov (United States)

    Masuzawa, Hiroshi; Tejima, Teruo; Harima, Katsushige; Morikawa, Takao

    1992-09-01

    Recently NIST has used the three-antenna method for calibration of the antenna factor of an antenna used for EMI measurements. This method does not require the specially designed standard antennas which are necessary in the standard field method or the standard antenna method, and can be used at an open-field test site. This paper theoretically and experimentally examines the measurement errors of this method and evaluates the precision of the antenna-factor calibration. It is found that the main source of the error is the non-ideal propagation characteristics of the test site, which should therefore be measured before the calibration. The precision of the antenna-factor calibration at the test site used in these experiments, is estimated to be 0.5 dB.

  3. 47 CFR 74.737 - Antenna location.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna location. 74.737 Section 74.737 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... Booster Stations § 74.737 Antenna location. (a) An applicant for a new low power TV, TV translator, or TV...

  4. 47 CFR 74.1237 - Antenna location.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna location. 74.1237 Section 74.1237 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... FM Broadcast Booster Stations § 74.1237 Antenna location. (a) An applicant for a new station to be...

  5. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2016-01-01

    of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a

  6. 47 CFR 73.753 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.753 Section 73.753 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES International Broadcast Stations § 73.753 Antenna systems. All international broadcasting stations shall operate...

  7. Active patch antennas for transponder applications

    Energy Technology Data Exchange (ETDEWEB)

    Biffi Gentili, G; Avitabile, G; Bonifacio, F; Salvador, C [Florence Univ. (Italy). Dip. di Ingegneria Elettronica

    1996-01-01

    The paper deals with two patch antenna structures that are mainly taught for short range link and non-contact identification system (RFID). The proposed antennas were developed by starting from an original concept of cross-polarization usefully applicable, in compliance with european for transponder applications are described and experimental results are reported.

  8. Multiband Patch Antenna for Femtocell Application

    Directory of Open Access Journals (Sweden)

    M. R. Zaman

    2014-01-01

    Full Text Available A microstrip patch antenna for multiple LTE (long term evaluation frequency bands for femtocell application is proposed in this paper. Distributed antenna solution (DAS has been introduced in cellular network to achieve homogenous indoor coverage. Femtocell is the latest extension to these solutions. It is a smart solution to both coverage and capacity scales. Femtocell operation in LTE band is occupied by higher frequency bands. For multiband femtocell application, miniature antenna design is quite essential. The antenna proposed here is composed of basic monopole structure with two parasitic elements at both sides of the active element. A rectangular slot is introduced at the ground plane of the proposed antenna. The antenna is designed using ElnoS HK light CCL substrate material of relative permittivity of 9.4, dielectric loss-tangent of 0.003 and thickness of 3 mm. The S11 response of the antenna is shown to have a bandwidth of 1.01 GHz starting from 1.79 GHz to 2.8 GHz. The characteristics of the antenna are analysed using Ansoft HFSS software.

  9. Waveguide Phased Array Antenna Analysis and Synthesis

    NARCIS (Netherlands)

    Visser, H.J.; Keizer, W.P.M.N.

    1996-01-01

    Results of two software packages for analysis and synthesis of waveguide phased array antennas are shown. The antennas consist of arrays of open-ended waveguides where irises can be placed in the waveguide apertures and multiple dielectric sheets in front of the apertures in order to accomplish a

  10. Antenna Design Exploiting the Duplex Isolation

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Pedersen, Gert Frølund

    2013-01-01

    A novel design addressing the antenna bandwidth issue for future communication standards on handsets is presented. It consists of a tunableantenna- pair for operation with a tunable front-end. The antennas are narrow-band and frequency-reconfigurable. This Letter focuses on the low communication ...

  11. Wireless SAW Sensors Having Integrated Antennas

    Science.gov (United States)

    Gallagher, Mark (Inventor); Malocha, Donald C. (Inventor)

    2015-01-01

    A wireless surface acoustic wave sensor includes a piezoelectric substrate, a surface acoustic wave device formed on the substrate, and an antenna formed on the substrate. In some embodiments, the antenna is formed on the surface of the substrate using one or more of photolithography, thin film processing, thick film processing, plating, and printing.

  12. GPS Antenna Data Needed : GPS Adjacent Band Compatibility Workshop Volpe Center, Cambridge MA

    Science.gov (United States)

    2014-09-18

    Topics. 1. Technical Objective: Receiver Antenna Mask and Electronics Data. 2. Definition of Receiver Antenna Mask. 3. Use of Receiver Antenna Mask. 4. Approaches to Generate the Antenna Mask. 5. Request for Receiver Antenna Data. 6. Next Steps.

  13. Reflectarray antennas theory, designs, and applications

    CERN Document Server

    Nayeri, Payam; Elsherbeni, Atef Z

    2018-01-01

    This book provides engineers with a comprehensive review of the state-of-the-art in reflectarray antenna research and development. The authors describe, in detail, design procedures for a wide range of applications, including broadband, multi-band, multi-beam, contour-beam, beam-scanning, and conformal reflectarray antennas. They provide sufficient coverage of basic reflectarray theory to fully understand reflectarray antenna design and analysis such that the readers can pursue reflectarray research on their own. Throughout the book numerous illustrative design examples including numerical and experimental results are provided. Featuring in-depth theoretical analysis along with practical design examples, Reflectarray Antennas is an excellent text/reference for engineering graduate students, researchers, and engineers in the field of antennas. It belongs on the bookshelves of university libraries, research institutes, and industrial labs and research facilities.

  14. Super wideband characteristics of monopolar patch antenna

    Directory of Open Access Journals (Sweden)

    Xi Chen

    2013-12-01

    Full Text Available A simple method of acquiring super wideband characteristics for monopolar patch antenna is proposed. Through adopting a modified cone as feeding and radiating structure, the monopolar patch antenna can reach the impedance bandwidth of more than 1:23.4 for voltage standing wave ratio (VSWR ≤ 2. In the whole operating band, the antenna has the like-monopole omnidirectional radiation patterns and the peak gains of 3.8–8.7 dB. Meanwhile, the height of the antenna is just 0.074λ(c, and the diameter of the radiated body is 0.205λ(c, which is smaller than other ultra-wideband omnidirectional antenna.

  15. Textile UWB Antenna Bending and Wet Performances

    Directory of Open Access Journals (Sweden)

    Mai A. R. Osman

    2012-01-01

    Full Text Available The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.

  16. Present and future JET ICRF antennae

    International Nuclear Information System (INIS)

    Kaye, A.; Brown, T.; Bhatnagar, V.; Crawley, P.; Jacquinot, J.; Lobel, R.; Plancoulaine, J.; Rebut, P.H.; Wade, T.; Walker, C.

    1994-01-01

    Since the initial operation of the JET ICRF system in 1985, up to 22 MW has been coupled to the plasma, many heating scenarios have been demonstrated and the main technological problem of RF-specific impurity production overcome. Many developments of the antennae have taken place over this period, notably the replacement of the water-cooled nickel screens with indirectly cooled beryllium screens, and the forthcoming installation of eight new A2 antennae for operation during the pumped divertor phase of JET. The A2 antennae include enhanced provision for fast wave current drive experiments on JET. This paper describes the beryllium screens, the technological results from operation and subsequent inspection of these screens, the design of the A2 antennae and the results from high power RF testing of a model of the A2 antenna. (orig.)

  17. 5G MIMO Conformal Microstrip Antenna Design

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2017-01-01

    Full Text Available With the development of wireless communication technology, 5G will develop into a new generation of wireless mobile communication systems. MIMO (multiple-input multiple-output technology is expected to be one of the key technologies in the field of 5G wireless communications. In this paper, 4 pairs of microstrip MIMO conformal antennas of 35 GHz have been designed. Eight-element microstrip Taylor antenna array with series-feeding not only achieves the deviation of the main lobe of the pattern but also increases the bandwidth of the antenna array and reduces sidelobe. MIMO antennas have been fabricated and measured. Measurement results match the simulation results well. The return loss of the antenna at 35 GHz is better than 20 dB, the first sidelobe level is −16 dB, and the angle between the main lobe and the plane of array is 60°.

  18. Antenna complexes protect Photosystem I from Photoinhibition

    Science.gov (United States)

    Alboresi, Alessandro; Ballottari, Matteo; Hienerwadel, Rainer; Giacometti, Giorgio M; Morosinotto, Tomas

    2009-01-01

    Background Photosystems are composed of two moieties, a reaction center and a peripheral antenna system. In photosynthetic eukaryotes the latter system is composed of proteins belonging to Lhc family. An increasing set of evidences demonstrated how these polypeptides play a relevant physiological function in both light harvesting and photoprotection. Despite the sequence similarity between antenna proteins associated with the two Photosystems, present knowledge on their physiological role is mostly limited to complexes associated to Photosystem II. Results In this work we analyzed the physiological role of Photosystem I antenna system in Arabidopsis thaliana both in vivo and in vitro. Plants depleted in individual antenna polypeptides showed a reduced capacity for photoprotection and an increased production of reactive oxygen species upon high light exposure. In vitro experiments on isolated complexes confirmed that depletion of antenna proteins reduced the resistance of isolated Photosystem I particles to high light and that the antenna is effective in photoprotection only upon the interaction with the core complex. Conclusion We show that antenna proteins play a dual role in Arabidopsis thaliana Photosystem I photoprotection: first, a Photosystem I with an intact antenna system is more resistant to high light because of a reduced production of reactive oxygen species and, second, antenna chlorophyll-proteins are the first target of high light damages. When photoprotection mechanisms become insufficient, the antenna chlorophyll proteins act as fuses: LHCI chlorophylls are degraded while the reaction center photochemical activity is maintained. Differences with respect to photoprotection strategy in Photosystem II, where the reaction center is the first target of photoinhibition, are discussed. PMID:19508723

  19. Telecommunications Antennas for the Juno Mission to Jupiter

    Science.gov (United States)

    Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.

    2012-01-01

    The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.

  20. Restoration of s-polarized evanescent waves and subwavelength imaging by a single dielectric slab

    International Nuclear Information System (INIS)

    El Gawhary, Omar; Schilder, Nick J; Costa Assafrao, Alberto da; Pereira, Silvania F; Paul Urbach, H

    2012-01-01

    It was predicted a few years ago that a medium with negative index of refraction would allow for perfect imaging. Although no material has been found so far that behaves as a perfect lens, some experiments confirmed the theoretical predictions in the near-field, or quasi-static, regime where the behaviour of a negative index medium can be mimicked by a thin layer of noble metal, such as silver. These results are normally attributed to the excitation of surface plasmons in the metal, which only leads to the restoration of p-polarized evanescent waves. In this work, we show that the restoration of s-polarized evanescent waves and, correspondingly, sub-wavelength imaging by a single dielectric slab are possible. Specifically, we show that at λ = 632 nm a thin layer of GaAs behaves as a superlens for s-polarized waves. Replacing the single-metal slab by a dielectric is not only convenient from a technical point of view, it being much easier to deposit and control the thickness and flatness of dielectric films than metal ones, but also invites us to re-think the connection between surface plasmon excitation and the theory of negative refraction. (paper)

  1. Polarization-selective infrared bandpass filter based on a two-layer subwavelength metallic grating

    Science.gov (United States)

    Hohne, Andrew J.; Moon, Benjamin; Baumbauer, Carol L.; Gray, Tristan; Dilts, James; Shaw, Joseph A.; Dickensheets, David L.; Nakagawa, Wataru

    2017-08-01

    We present the design, fabrication, and characterization of a polarization-selective infrared bandpass filter based on a two-layer subwavelength metallic grating for use in polarimetric imaging. Gold nanowires were deposited via physical vapor deposition (PVD) onto a silicon surface relief grating that was patterned using electron beam lithography (EBL) and fabricated using standard silicon processing techniques. Optical characterization with a broad-spectrum tungsten halogen light source and a grating spectrometer showed normalized peak TM transmission of 53% with a full-width at half-maximum (FWHM) of 122 nm, which was consistent with rigorous coupled-wave analysis (RCWA) simulations. Simulation results suggested that device operation relied on suppression of the TM transmission caused by surface plasmon polariton (SPP) excitation at the gold-silicon interface and an increase in TM transmission caused by a Fabry-Perot (FP) resonance in the cavity between the gratings. TE rejection occurred at the initial air/gold interface. We also present simulation results of an improved design based on a two-dielectric grating where two different SPP resonances allowed us to improve the shape of the passband by suppressing the side lobes. This newer design resulted in improved side-band performance and increased peak TM transmission.

  2. Methodology for balancing design and process tradeoffs for deep-subwavelength technologies

    Science.gov (United States)

    Graur, Ioana; Wagner, Tina; Ryan, Deborah; Chidambarrao, Dureseti; Kumaraswamy, Anand; Bickford, Jeanne; Styduhar, Mark; Wang, Lee

    2011-04-01

    For process development of deep-subwavelength technologies, it has become accepted practice to use model-based simulation to predict systematic and parametric failures. Increasingly, these techniques are being used by designers to ensure layout manufacturability, as an alternative to, or complement to, restrictive design rules. The benefit of model-based simulation tools in the design environment is that manufacturability problems are addressed in a design-aware way by making appropriate trade-offs, e.g., between overall chip density and manufacturing cost and yield. The paper shows how library elements and the full ASIC design flow benefit from eliminating hot spots and improving design robustness early in the design cycle. It demonstrates a path to yield optimization and first time right designs implemented in leading edge technologies. The approach described herein identifies those areas in the design that could benefit from being fixed early, leading to design updates and avoiding later design churn by careful selection of design sensitivities. This paper shows how to achieve this goal by using simulation tools incorporating various models from sparse to rigorously physical, pattern detection and pattern matching, checking and validating failure thresholds.

  3. Sub-wavelength plasmonic readout for direct linear analysis of optically tagged DNA

    Science.gov (United States)

    Varsanik, Jonathan; Teynor, William; LeBlanc, John; Clark, Heather; Krogmeier, Jeffrey; Yang, Tian; Crozier, Kenneth; Bernstein, Jonathan

    2010-02-01

    This work describes the development and fabrication of a novel nanofluidic flow-through sensing chip that utilizes a plasmonic resonator to excite fluorescent tags with sub-wavelength resolution. We cover the design of the microfluidic chip and simulation of the plasmonic resonator using Finite Difference Time Domain (FDTD) software. The fabrication methods are presented, with testing procedures and preliminary results. This research is aimed at improving the resolution limits of the Direct Linear Analysis (DLA) technique developed by US Genomics [1]. In DLA, intercalating dyes which tag a specific 8 base-pair sequence are inserted in a DNA sample. This sample is pumped though a nano-fluidic channel, where it is stretched into a linear geometry and interrogated with light which excites the fluorescent tags. The resulting sequence of optical pulses produces a characteristic "fingerprint" of the sample which uniquely identifies any sample of DNA. Plasmonic confinement of light to a 100 nm wide metallic nano-stripe enables resolution of a higher tag density compared to free space optics. Prototype devices have been fabricated and are being tested with fluorophore solutions and tagged DNA. Preliminary results show evanescent coupling to the plasmonic resonator is occurring with 0.1 micron resolution, however light scattering limits the S/N of the detector. Two methods to reduce scattered light are presented: index matching and curved waveguides.

  4. Acoustic transmission resonance and suppression through double-layer subwavelength hole arrays

    International Nuclear Information System (INIS)

    Liu Zhifeng; Jin Guojun

    2010-01-01

    We present a theoretical study of acoustic waves passing through double-layer subwavelength hole arrays. The acoustic transmission resonance and suppression are observed. There are three mechanisms responsible for the transmission resonance: the excitation of geometrically induced acoustic surface waves, the Fabry-Perot resonance in a hole cavity (I-FP resonance) and the Fabry-Perot resonance between two plates (II-FP resonance). We can differentiate these mechanisms via the dispersion relation of acoustic modes supported by the double-layer structure. It is confirmed that the coupling between two single-layer perforated plates, associated with longitudinal interval and lateral displacement, plays a crucial role in modulating the transmission properties. The strong coupling between two plates can induce the splitting of the transmission peak, while the decoupling between plates leads to the appearance of transmission suppression. By analyzing the criterion derived for transmission suppression, we conclude that it is the destructive interference between the diffracted waves and the direct transmission waves assisted by the I-FP resonance of the first plate that leads to the decoupling between plates and then the transmission suppression.

  5. Sub-wavelength patterning of organic monolayers via nonlinear processing with continuous-wave lasers

    Energy Technology Data Exchange (ETDEWEB)

    Mathieu, Mareike; Hartmann, Nils, E-mail: nils.hartmann@uni-due.de [Fakultaet fuer Chemie, Universitaet Duisburg-Essen, 45117 Essen (Germany); CeNIDE-Center for Nanointegration Duisburg-Essen, 47048 Duisburg (Germany); NETZ-NanoEnergieTechnikZentrum, 47048 Duisburg (Germany)

    2010-12-15

    In recent years, nonlinear processing with continuous-wave lasers has been demonstrated to be a facile means of rapid nanopatterning of organic monolayers down to the sub-100 nm range. In this study, we report on laser patterning of thiol-based organic monolayers with sub-wavelength resolution. Au-coated silicon substrates are functionalized with 1-hexadecanethiol. Irradiation with a focused beam of an Ar{sup +} laser operating at {lambda}=514 nm allows one to locally remove the monolayer. Subsequently, the patterns are transferred into the Au film via selective etching in a ferri-/ferrocyanide solution. Despite a 1/e{sup 2} spot diameter of about 2.8 {mu}m, structures with lateral dimensions down to 250 nm are fabricated. The underlying nonlinear dependence of the patterning process on laser intensity is traced back to the interplay between the laser-induced transient local temperature rise and the thermally activated desorption of the thiol molecules. A simple thermokinetic analysis of the data allows us to determine the effective kinetic parameters. These results complement our previous work on photothermal laser patterning of ultrathin organic coatings, such as silane-based organic monolayers, organo/silicon interfaces and supported membranes. A general introduction to nonlinear laser processing of organic monolayers is presented.

  6. Design of a Fused-Silica Subwavelength Polarizing Beam Splitter Grating Based on the Modal Method

    International Nuclear Information System (INIS)

    Hua-Jun, Zhao; Dai-Rong, Yuan; Pei, Wang; Yong-Hua, Lu; Hai, Ming

    2010-01-01

    A polarizing beam splitter (PBS) design based on a fused-silica lamellar subwavelength transmission grating is demonstrated with the modal method, where TE- and TM-polarized waves are mainly diffracted in the −1 st and 0 th orders, respectively. The physical explanation of the grating diffraction is illustrated by the interference of the corresponding parts of the two propagating modes, which is very similar to a Mach–Zehnder interferometer. It is shown that diffraction efficients over 99% for a TM-polarized wave in the −1 st order and 90% for a TE-polarized wave in the 0 th order are obtained at the wavelength of 1.053 μm. The polarization transmission extinction ratios are better than 33 dB and 51 dB for the order 0 th and the −1 st order, respectively. The splitting properties of the PBS grating designed by the modal method are in good agreement with the results simulated by the rigorous coupled wave analysis method. (fundamental areas of phenomenology(including applications))

  7. Simple fabrication of antireflective silicon subwavelength structure with self-cleaning properties.

    Science.gov (United States)

    Kim, Bo-Soon; Ju, Won-Ki; Lee, Min-Woo; Lee, Cheon; Lee, Seung-Gol; Beom-Hoan, O

    2013-05-01

    A subwavelength structure (SWS) was formed via a simple chemical wet etching using a gold (Au) catalyst. Single nano-sized Au particles were fabricated by metallic self-aggregation. The deposition and thermal annealing of the thin metallic film were carried out. Thermal annealing of a thin metallic film enables the creation of metal nano particles by isolating them from each other by means of the self-aggregation of the metal. After annealing, the samples were soaked in an aqueous etching solution of hydrofluoric acid and hydrogen peroxide. When silicon (Si) was etched for 2 minutes using the Au nano particles, the reflectance was decreased almost 0% over the entire wavelength range from 300 to 1300 nm due to its deep and steeply double tapered structure. When given varying incident angle degrees from 30 degrees to 60 degrees, the reflectance was also maintained at less than 3%. Following this, the etched silicon was treated with a plasma-polymerized fluorocarbon (PPFC) film of about 5 nm using an ICP reactor for surface modification. The result of this surface treatment, the contact angle increased significantly from 27.5 degrees to 139.3 degrees. The surface modification was successful and maintained almost 0% reflectance because of the thin film deposition.

  8. Geometrical tuning art for entirely subwavelength grating waveguide based integrated photonics circuits.

    Science.gov (United States)

    Wang, Zheng; Xu, Xiaochuan; Fan, Donglei; Wang, Yaguo; Subbaraman, Harish; Chen, Ray T

    2016-05-05

    Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to the extra degree of freedom it offers in tuning a few important waveguide properties, such as dispersion and refractive index. Devices based on SWG waveguides have demonstrated impressive performances compared to conventional waveguides. However, the high loss of SWG waveguide bends jeopardizes their applications in integrated photonic circuits. In this work, we propose a geometrical tuning art, which realizes a pre-distorted refractive index profile in SWG waveguide bends. The pre-distorted refractive index profile can effectively reduce the mode mismatch and radiation loss simultaneously, thus significantly reduce the bend loss. This geometry tuning art has been numerically optimized and experimentally demonstrated in present study. Through such tuning, the average insertion loss of a 5 μm SWG waveguide bend is reduced drastically from 5.43 dB to 1.10 dB per 90° bend for quasi-TE polarization. In the future, the proposed scheme will be utilized to enhance performance of a wide range of SWG waveguide based photonics devices.

  9. Low-loss curved subwavelength grating waveguide based on index engineering

    Science.gov (United States)

    Wang, Zheng; Xu, Xiaochuan; Fan, D. L.; Wang, Yaoguo; Chen, Ray T.

    2016-03-01

    Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to its freedom to tune a few important waveguide properties such as dispersion and refractive index. Devices based on SWG waveguide have demonstrated impressive performances compared to those of conventional waveguides. However, the large loss of SWG waveguide bends jeopardizes their applications in integrated photonics circuits. In this work, we propose that a predistorted refractive index distribution in SWG waveguide bends can effectively decrease the mode mismatch noise and radiation loss simultaneously, and thus significantly reduce the bend loss. Here, we achieved the pre-distortion refractive index distribution by using trapezoidal silicon pillars. This geometry tuning approach is numerically optimized and experimentally demonstrated. The average insertion loss of a 5 μm SWG waveguide bend can be reduced drastically from 5.58 dB to 1.37 dB per 90° bend for quasi-TE polarization. In the future, the proposed approach can be readily adopted to enhance performance of an array of SWG waveguide-based photonics devices.

  10. Space-coiling fractal metamaterial with multi-bandgaps on subwavelength scale

    Science.gov (United States)

    Man, Xianfeng; Liu, Tingting; Xia, Baizhan; Luo, Zhen; Xie, Longxiang; Liu, Jian

    2018-06-01

    Acoustic metamaterials are remarkably different from conventional materials, as they can flexibly manipulate and control the propagation of sound waves. Unlike the locally resonant metamaterials introduced in earlier studies, we designed an ultraslow artificial structure with a sound speed much lower than that in air. In this paper, the space-coiling approach is proposed for achieving artificial metamaterial for extremely low-frequency airborne sound. In addition, the self-similar fractal technique is utilized for designing space-coiling Mie-resonance-based metamaterials (MRMMs) to obtain a band-dispersive spectrum. The band structures of two-dimensional (2D) acoustic metamaterials with different fractal levels are illustrated using the finite element method. The low-frequency bandgap can easily be formed, and multi-bandgap properties are observed in high-level fractals. Furthermore, the designed MRMMs with higher order fractal space coiling shows a good robustness against irregular arrangement. Besides, the proposed artificial structure was found to modify and control the radiation field arbitrarily. Thus, this work provides useful guidelines for the design of acoustic filtering devices and acoustic wavefront shaping applications on the subwavelength scale.

  11. Transmittance enhancement of sapphires with antireflective subwavelength grating patterned UV polymer surface structures by soft lithography.

    Science.gov (United States)

    Lee, Soo Hyun; Leem, Jung Woo; Yu, Jae Su

    2013-12-02

    We report the total and diffuse transmission enhancement of sapphires with the ultraviolet curable SU8 polymer surface structures consisting of conical subwavelength gratings (SWGs) at one- and both-side surfaces for different periods. The SWGs patterns on the silicon templates were transferred into the SU8 polymer film surface on sapphires by a simple and cost-effective soft lithography technique. For the fabricated samples, the surface morphologies, wetting behaviors, and optical characteristics were investigated. For theoretical optical analysis, a rigorous coupled-wave analysis method was used. At a period of 350 nm, the sample with SWGs on SU8 film/sapphire exhibited a hydrophobic surface and higher total transmittance compared to the bare sapphire over a wide wavelength of 450-1000 nm. As the period of SWGs was increased, the low total transmittance region of < 85% was shifted towards the longer wavelengths and became broader while the diffuse transmittance was increased (i.e., larger haze ratio). For the samples with SWGs at both-side surfaces, the total and diffuse transmittance spectra were further enhanced compared to the samples with SWGs at one-side surface. The theoretical optical calculation results showed a similar trend to the experimentally measured data.

  12. Waveguide resonance mode response of stacked structures of metallic sub-wavelength slit arrays

    Science.gov (United States)

    Tokuda, Yasunori; Takano, Keisuke; Sakaguchi, Koichiro; Kato, Kosaku; Nakajima, Makoto; Akiyama, Koichi

    2018-05-01

    Detailed measurements of the optical properties of two-tier systems composed of metallic plates perforated with periodic sub-wavelength slit patterns were carried out using terahertz time-domain spectroscopy. We demonstrate that the transmission properties observed experimentally for various configurations can be reproduced successfully by simulations based on the finite-differential time-domain method. Fabry-Perot-like waveguide resonance mode behaviors specific to this quasi-dielectric system were then investigated. For structures with no lateral displacement between the slit-array plates, mode disappearance phenomena, which are caused by destructive interference between the odd-order mode and the blue- or red-shifted even-order modes, were observed experimentally. The uncommon behavior of the even-order modes was examined precisely to explain the slit-width dependence. For structures with half-pitched displacement between the plates, extraordinarily strong transmission was observed experimentally, even when the optical paths were shut off. This result was interpreted in terms of the propagation of surface plasmon polaritons through very thin and labyrinthine spacings that inevitably exist between the metallic plates. Furthermore, the optical mode disappearance phenomena are revealed to be characterized by anticrossing of the two mixing modes formed by even- and odd-order modes. These experimental observations that are supported theoretically are indispensable to the practical use of this type of artificial dielectric and are expected to encourage interest in optical mode behaviors that are not typically observed in conventional dielectric systems.

  13. Approaching total absorption of graphene strips using a c-Si subwavelength periodic membrane

    Science.gov (United States)

    Sang, Tian; Wang, Rui; Li, Junlang; Zhou, Jianyu; Wang, Yueke

    2018-04-01

    Approaching total absorption of graphene strips at near infrared using a crystalline-silicon (c-Si) subwavelength periodic membrane (SPM) is presented. The absorption in graphene strips in a c-Si SPM is enhanced by a resonant tip, which is resulted from the coupling between the guided mode and the radiation mode through symmetry breaking of the structure at near-normal incidence. The enhancement of the electric field intensity is increased 1939 times and the group velocity of light is decreased to 3.55 ×10-4c at resonance, and 99.3% absorption in graphene strips can be achieved by critical coupling at the incident angle of 2°. High absorption of the graphene strips can be maintained as the etching thickness, the strip width, and the period are altered. When this type of c-Si SPM with graphene strips is used in refractive index sensors, it shows excellent sensing properties due to its stable near-unity absorption.

  14. A self-adaptive metamaterial beam with digitally controlled resonators for subwavelength broadband flexural wave attenuation

    Science.gov (United States)

    Li, Xiaopeng; Chen, Yangyang; Hu, Gengkai; Huang, Guoliang

    2018-04-01

    Designing lightweight materials and/or structures for broadband low-frequency noise/vibration mitigation is an issue of fundamental importance both practically and theoretically. In this paper, by leveraging the concept of frequency-dependent effective stiffness control, we numerically and experimentally demonstrate, for the first time, a self-adaptive metamaterial beam with digital circuit controlled mechanical resonators for strong and broadband flexural wave attenuation at subwavelength scales. The digital controllers that are capable of feedback control of piezoelectric shunts are integrated into mechanical resonators in the metamaterial, and the transfer function is semi-analytically determined to realize an effective bending stiffness in a quadratic function of the wave frequency for adaptive band gaps. The digital as well as analog control circuits as the backbone of the system are experimentally realized with the guarantee stability of the whole electromechanical system in whole frequency regions, which is the most challenging problem so far. Our experimental results are in good agreement with numerical predictions and demonstrate the strong wave attenuation in almost a three times larger frequency region over the bandwidth of a passive metamaterial. The proposed metamaterial could be applied in a range of applications in the design of elastic wave control devices.

  15. Design of silicon-based fractal antennas

    KAUST Repository

    Ghaffar, Farhan A.

    2012-11-20

    This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

  16. Design of silicon-based fractal antennas

    KAUST Repository

    Ghaffar, Farhan A.; Shamim, Atif

    2012-01-01

    This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

  17. Scalable Notch Antenna System for Multiport Applications

    Directory of Open Access Journals (Sweden)

    Abdurrahim Toktas

    2016-01-01

    Full Text Available A novel and compact scalable antenna system is designed for multiport applications. The basic design is built on a square patch with an electrical size of 0.82λ0×0.82λ0 (at 2.4 GHz on a dielectric substrate. The design consists of four symmetrical and orthogonal triangular notches with circular feeding slots at the corners of the common patch. The 4-port antenna can be simply rearranged to 8-port and 12-port systems. The operating band of the system can be tuned by scaling (S the size of the system while fixing the thickness of the substrate. The antenna system with S: 1/1 in size of 103.5×103.5 mm2 operates at the frequency band of 2.3–3.0 GHz. By scaling the antenna with S: 1/2.3, a system of 45×45 mm2 is achieved, and thus the operating band is tuned to 4.7–6.1 GHz with the same scattering characteristic. A parametric study is also conducted to investigate the effects of changing the notch dimensions. The performance of the antenna is verified in terms of the antenna characteristics as well as diversity and multiplexing parameters. The antenna system can be tuned by scaling so that it is applicable to the multiport WLAN, WIMAX, and LTE devices with port upgradability.

  18. Validating and comparing GNSS antenna calibrations

    Science.gov (United States)

    Kallio, Ulla; Koivula, Hannu; Lahtinen, Sonja; Nikkonen, Ville; Poutanen, Markku

    2018-03-01

    GNSS antennas have no fixed electrical reference point. The variation of the phase centre is modelled and tabulated in antenna calibration tables, which include the offset vector (PCO) and phase centre variation (PCV) for each frequency according to the elevations and azimuths of the incoming signal. Used together, PCV and PCO reduce the phase observations to the antenna reference point. The remaining biases, called the residual offsets, can be revealed by circulating and rotating the antennas on pillars. The residual offsets are estimated as additional parameters when combining the daily GNSS network solutions with full covariance matrix. We present a procedure for validating the antenna calibration tables. The dedicated test field, called Revolver, was constructed at Metsähovi. We used the procedure to validate the calibration tables of 17 antennas. Tables from the IGS and three different calibration institutions were used. The tests show that we were able to separate the residual offsets at the millimetre level. We also investigated the influence of the calibration tables from the different institutions on site coordinates by performing kinematic double-difference baseline processing of the data from one site with different antenna tables. We found small but significant differences between the tables.

  19. Smart antennas for nuclear instruments

    International Nuclear Information System (INIS)

    Jain, Ranjan Bala; Singhi, B.M.

    2005-01-01

    The advances in the field of computer and communications are leading to the development of smart embedded nuclear instruments. These instruments have highly sophisticated signal-processing algorithms based on FPGA and ASICS, provisions of present day connectivity and user interfaces. The developments in the connectivity, standards and bus technologies have made possible to access these instruments on LAN and WAN with suitable reliability and security. To get rid of wires i.e. in order to access these instruments, without wires at any place, wireless technology has evolved and become integral part of day-to-day activities. The environment monitoring can be done remotely, if smart antennas are incorporated on these instruments

  20. Passive Microwave Components and Antennas

    DEFF Research Database (Denmark)

    State-of-the-art microwave systems always require higher performance and lower cost microwave components. Constantly growing demands and performance requirements of industrial and scientific applications often make employing traditionally designed components impractical. For that reason, the design...... and development process remains a great challenge today. This problem motivated intensive research efforts in microwave design and technology, which is responsible for a great number of recently appeared alternative approaches to analysis and design of microwave components and antennas. This book highlights...... techniques. Modelling and computations in electromagnetics is a quite fast-growing research area. The recent interest in this field is caused by the increased demand for designing complex microwave components, modeling electromagnetic materials, and rapid increase in computational power for calculation...

  1. CPW to CPS transition for feeding UWB antennas

    DEFF Research Database (Denmark)

    Butrym, Alexander; Pivnenko, Sergey

    2004-01-01

    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas in particular), bow-tie antennas, and other. Some numerical and experimental results...

  2. CPW to CPS transition for feeding UWB antennas

    DEFF Research Database (Denmark)

    Butrym, Alexander; Pivnenko, Sergey

    2006-01-01

    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas, in particular), bow-tie antennas, and other. Some numerical and experimental results...

  3. Logo Antenna for 5.8 GHz Wireless Communications (invited)

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A logo antenna for the 5.8 GHz ISM band is presented. The idea behind the logo antenna is to use the company or university logo as part of the antenna. When disguised as a logo, it may be more acceptable to place the antenna at optimal locations to obtain good coverage. In the present work...

  4. Logo Antenna for 5.8 GHz Wireless Communications

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A logo antenna for the 5.8 GHz ISM band is presented. The idea behind the logo antenna is to use the company or university logo as part of the antenna. When disguised as a logo, it may be more acceptable to place the antenna at optimal locations to obtain good coverage. In the present work...

  5. Aerogel-Based Antennas for Aerospace and Terrestrial Applications

    Science.gov (United States)

    Meador, Mary Ann (Inventor); Miranda, Felix (Inventor); Van Keuls, Frederick (Inventor)

    2016-01-01

    Systems and methods for lightweight, customizable antenna with improved performance and mechanical properties are disclosed. In some aspects, aerogels can be used, for example, as a substrate for antenna fabrication. The reduced weight and expense, as well as the increased ability to adapt antenna designs, permits a systems to mitigate a variety of burdens associated with antennas while providing added benefits.

  6. 47 CFR 73.54 - Antenna resistance and reactance measurements.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna resistance and reactance measurements... measurements. (a) The resistance of an omnidirectional series fed antenna is measured at either the base of the... the point of common radiofrequency input to the directional antenna system after the antenna has been...

  7. Slot Antenna for Wireless Temperature Measurement Systems

    DEFF Research Database (Denmark)

    Acar, Öncel; Jakobsen, Kaj Bjarne

    2016-01-01

    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

  8. Rectifying antenna and method of manufacture

    Science.gov (United States)

    Bhansali, Shekhar (Inventor); Buckle, Kenneth (Inventor); Goswami, D. Yogi (Inventor); Stefanakos, Elias (Inventor); Weller, Thomas (Inventor)

    2006-01-01

    In accordance with the present invention, an aperture rectenna is provided where the substrate is transparent and of sufficient mechanical strength to support the fabricated structure above it. An aperture antenna is deposited on the transparent substrate and a metal-insulator-metal (MIM) diode is constructed on top of the aperture antenna. There is an insulating layer between the aperture antenna metal and the metal ground plane optimized to maximize the collection of incident radiation. The top of the structure is capped with a metal ground plane layer, which also serves as the DC connection points for each rectenna element.

  9. FDTD simulation tools for UWB antenna analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2005-02-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  10. FDTD simulation tools for UWB antenna analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2004-12-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  11. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2015-01-01

    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

  12. Resonant double loop antenna development at ORNL

    International Nuclear Information System (INIS)

    Taylor, D.J.; Baity, F.W.; Brown, R.A.; Bryan, W.E.; Fadnek, A.; Hoffman, D.J.; King, J.F.; Livesey, R.L.; McIlwain, R.L.

    1988-01-01

    As part of the development of ion cyclotron resonant heating (ICRH) systems for fusion research, Oak Ridge National Laboratory (ORNL) has built resonant double loop (RDL) antennas for the Tokamak Fusion Test Reactor (TFTR) (Princeton Plasma Physics Laboratory, Princeton, NJ, US) and Tore Supra (Centre d'Etudes Nucleaire, Cadarache, France). Each antenna has been designed to deliver 4 MW of power. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments lead to substantial differences in the designs of specific components. A description and a comparison of the technologies developed in the two designs are presented. 5 refs., 4 figs., 1 tab

  13. MIMO Communication Using Single Feed Antenna Arrays

    DEFF Research Database (Denmark)

    Alrabadi, Osama

    Multi-input-multi-output (MIMO) communication has emerged as a promis- ing technology for meeting the increasing demand on higher data rates. The technology exploits the spatial resource dimension by sending the datas- treams to different locations in the multi element array (MEA) domain while...... conventionally to a single antenna element while mod- ulating the other datastreams in the analogue RF domain, using simple switched antenna systems (SAS) or sophisticated reactance-assisted antenna systems. The use of a SAS is found simple to implement, but can hardly handle high order signal formats...

  14. Implanted Antennas in Medical Wireless Communications

    CERN Document Server

    Rahmat-Samii, Yahya; Balanis, Constantine

    2006-01-01

    Implanted Antennas in Medical Wireless Communications summarizes the results of recent research activities on the subject of implanted antennas for medical wireless communication systems. It is anticipated that in the near future sophisticated medical devices will be implanted inside the human body for medical telemetry and telemedicine. To establish effective and efficient wireless links with these devices, it is pivotal to give special attention to antenna designs that are low profile, small, safe, and cost effective. In this book, authors Yahya Rahmat-Samii and Jaehoon Kim demonstrate how a

  15. The principles of radio engineering and antennas. II Antennas (2nd revised and enlarged edition)

    Science.gov (United States)

    Belotserkovskii, G. B.

    This book represents the second part of a textbook for technical schools. The characteristics and parameters of antennas are considered along with transmission lines, the theory of single dipoles and radiator systems, and the technological realization of elements and units of the antenna-feeder system, taking into account filters and multiport networks for microwave communications applications, and ferrite circulators and isolators. The first edition of this textbook was published in 1969. For the current edition, the material in the first edition has been revised, and new material has been introduced. Much attention is given to microwave antennas, including, in particular, arrays with electrical scanning characteristics. Other topics discussed are related to the general principles of antennas, the matching of the impedance of transmission lines, the elements of transmission lines, aperture-type antennas for microwaves, and the functional characteristics of antennas for ultrashort waves.

  16. A Fast Adaptive Receive Antenna Selection Method in MIMO System

    Directory of Open Access Journals (Sweden)

    Chaowei Wang

    2013-01-01

    Full Text Available Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

  17. Compact antennas for wireless communications and terminals theory and design

    CERN Document Server

    Laheurte, Jean-Marc

    2012-01-01

    Compact Antennas for Wireless Communications and Terminals deals with compact microwave antennas and, more specifically, with the planar version of these antennas. Planar antennas are the most appropriate type of antenna in modern communication systems and more generally in all applications requiring miniaturization, integration and conformation such as in mobile phone handsets.The book is suitable for students, engineers and scientists eager to understand the principles of planar and small antennas, their design and fabrication issues, and modern aspects such as UWB antennas, recon

  18. Low-Q Electrically Small Spherical Magnetic Dipole Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2010-01-01

    Three novel electrically small antenna configurations radiating a TE10 spherical mode corresponding to a magnetic dipole are presented and investigated: multiarm spherical helix (MSH) antenna, spherical split ring resonator (S-SRR) antenna, and spherical split ring (SSR) antenna. All three antennas...... are self-resonant, with the input resistance tuned to 50 ohms by an excitation curved dipole/monopole. A prototype of the SSR antenna has been fabricated and measured, yielding results that are consistent with the numerical simulations. Radiation quality factors (Q) of these electrically small antennas (in...

  19. Wireless communication capability of a reconfigurable plasma antenna

    International Nuclear Information System (INIS)

    Kumar, Rajneesh; Bora, Dhiraj

    2011-01-01

    A 30 cm long plasma column is excited by a surface wave, which acts as a plasma antenna. Using plasma properties (pattern formation/striations in plasmas) single plasma antenna can be transformed into array, helical, and spiral plasma antenna. Experiments are carried out to study the power patterns, directivity, and half power beam width of such different plasma antennas. Moreover, field properties of plasma and copper antenna are studied. Further, wireless communication and jamming capability of plasma antenna are tested. Findings of this study suggest that directivity and communication range can be increased by converting single plasma antenna in to array/helical/spiral plasma antenna. Field frequencies of plasma antenna determine the communication and jamming of radio frequency waves. Therefore, this study invokes applications of pattern formation or striations of plasmas in plasma antenna technology.

  20. Fluorescence Enhancement Factors on Optical Antennas: Enlarging the Experimental Values without Changing the Antenna Design

    Directory of Open Access Journals (Sweden)

    Jérôme Wenger

    2012-01-01

    Full Text Available Plasmonic antennas offer promising opportunities to control the emission of quantum objects. As a consequence, the fluorescence enhancement factor is widely used as a figure of merit for a practical antenna realization. However, the fluorescence enhancement factor is not an intrinsic property of the antenna. It critically depends on several parameters, some of which are often disregarded. In this contribution, I explore the influence of the setup collection efficiency, emitter's quantum yield, and excitation intensity. Improperly setting these parameters may significantly alter the enhancement values, leading to potential misinterpretations. The discussion is illustrated by an antenna example of a nanoaperture surrounded by plasmonic corrugations.

  1. Planar Millimeter-Wave Antennas: A Comparative Study

    Directory of Open Access Journals (Sweden)

    K. Pitra

    2011-04-01

    Full Text Available The paper describes the design and the experimental verification of three types of wideband antennas. Attention is turned to the bow-tie antenna, the Vivaldi antenna and the spiral antenna designed for the operation at millimeter waves. Bandwidth, input impedance, gain, and directivity pattern are the investigated parameters. Antennas are compared considering computer simulations in CST Microwave Studio and measured data.

  2. Sub-wavelength grating structure on the planar waveguide (Conference Presentation)

    Science.gov (United States)

    Qing-Song, Zhu; Sheng-Hui, Chen

    2016-10-01

    Making progress in recent years, with the technology of the grating, the grating period can be reduced to shrink the size of the light coupler on a waveguide. The working wavelength of the light coupler can be in the range from the near-infrared to visible. In this study , we used E-gun evaporation system with ion-beam-assisted deposition system to fabricate bottom cladding (SiO2), guiding layer (Ta2O5) and Distributed Bragg Reflector(DBR) of the waveguide on the silicon substrate. Electron-beam lithography is used to make sub-wavelength gratings and reflector grating on the planar waveguide which is a coupling device on the guiding layer. The best fabrication parameters were analyzed to deposit the film. The exposure and development times also influenced to fabricate the grating quality. The purpose is to reduce the device size and enhance coupling efficiency which maintain normal incidence of the light . We designed and developed the device using the Finite-Difference Time-Domain (FDTD) method. The grating period, depth, fill factor, film thickness, Distributed Bragg Reflector(DBR) numbers and reflector grating period have been discussed to enhance coupling efficiency and maintained normal incidence of the light. According to the simulation results, when the wavelength is 1300 nm, the coupling grating period is 720 nm and the Ta2O5 film is 460 nm with 360 nm of reflector grating period and 2 layers of Distributed Bragg Reflector, which had the optimum coupling efficiency and normal incidence angle. In the measurement, We successfully measured the TE wave coupling efficiency of the photoresist grating coupling device.

  3. Stockbridge Antenna Measurement and Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Stockbridge Antenna Measurement Facility is located 23 miles southwest of AFRL¹s Rome Research Site. This unique measurement facility is designed to evaluate the...

  4. Antenna Miniaturization in Complex Electromagnetic Environments

    DEFF Research Database (Denmark)

    Zhang, Jiaying

    improved compared to the 2-D planar electrically small loop antennas. Measurement Techniques for ESAs In this dissertation we proposed two novel measurement techniques for electrically small antennas. A modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small....... Moreover, the modified Wheeler cap method for measurements of small antennas in complex environments is further developed. A cable-free impedance and gain measurement technique for electrically small antennas is also proposed. The electromagnetic model of this technique is derived by using the spherical...... wave expansion, and it is valid for arbitrary electrically small AUT at arbitrary distances between the probe and AUT. The whole measurement setup is modeled by the cascade of three coupled multipleort networks. The electromagnetic model, the simulation results, and the obtained measurement results...

  5. Visualization of electromagnetic exposure near LTE antennae

    Science.gov (United States)

    Zvezdina, M. Yu; Shokova, Yu A.; Nazarova, O. Yu; Al-Ali, H. T. A.; Al-Farhan, G. H. A.

    2018-01-01

    Technical progress in wireless data transfer has given an opportunity to apply information and communication technologies in various areas of economics. Digital economy is linked to the 4th and 5th generation mobile network deployment. The peculiarities of the abovementioned standards decrease BTS antenna range three times in dense developed areas and worsen electromagnetic background in big cities. In the paper the comparative assessment results for rooftop electromagnetic exposure near BTS LTE and BTS GSM antennae are given. It is shown, that at the same level of transmitter power, energy flux density for LTE standard is three times less than the one for GSM. Moreover, the conclusion is made that the rooftop could be considered safe for people for indefinite time if antenna is placed more than 5 meters above the rooftop. The value of antenna height is taken to be on the safe side, as it is required by an application of “preventive principle”.

  6. Phase shifter for antenna beam steering

    Energy Technology Data Exchange (ETDEWEB)

    Jindal, Ravi, E-mail: rjindal21@gmail.com [Master’s(MS) in System Electronics and General Electrical, Ecole Polytechnique of university of Nantes France, IETR, Nantes (France); Razban, Tchanguiz, E-mail: tchanguiz.razban-haghighi@univ-nantes.fr [Electronics and Telecommunication Institute of Rennes (IETR-UMR 6164), Ecole Polytechnique of university of Nantes France, IETR, Nantes (France)

    2016-03-09

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  7. GBO RF Anechoic Chamber & Antenna Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  8. Phase shifter for antenna beam steering

    International Nuclear Information System (INIS)

    Jindal, Ravi; Razban, Tchanguiz

    2016-01-01

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  9. A Modal Description of Multiport Antennas

    Directory of Open Access Journals (Sweden)

    Jonathan J. Lynch

    2011-01-01

    Full Text Available This paper presents a modal description of multiport antennas that leads directly to a rigorous network representation and simple quadratic expressions for gain, efficiency, and effective area. The analysis shows that the transmitting and receiving properties of an element antenna array are exactly described by a 2×2 element scattering matrix together with a set of orthonormal mode functions and accounts for effects such as mutual coupling, scattering, reflection, and losses. The approach is quite general, only requiring that the antenna be finite and reciprocal. The scattering network description simplifies accounting of power flow while retaining a close connection to the physical antenna characteristics. The orthonormal mode functions provide a complete basis for radiated and received fields, facilitating beamforming. The theory provides rigorous definitions of input-output signals and links them to the underlying electromagnetics in a straightforward manner.

  10. Multiband Photonic Phased-Array Antenna

    Science.gov (United States)

    Tang, Suning

    2015-01-01

    A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

  11. Development of ceramic-free antenna feeder

    International Nuclear Information System (INIS)

    Moriyama, S.; Kimura, H.; Fujii, T.; Saigusa, M.; Arai, H.

    1994-01-01

    We have proposed a ceramics-free antenna feeder line employing a ridged waveguide as a local support for IC antenna of next-generation tokamaks. One fourth mock-up model of the all metal waveguide designed for the ITER ICRF system is fabricated and electrical characteristics of the model including the coaxial line - waveguide converter are measured. Power reflection coefficient of the model including the coax-waveguide converter to the input coaxial line is estimated to be less than 15% below the cut-off frequency of 107 MHz and less than 3% above the cut-off frequency. It is found that this ceramics-free antenna support employing a ridged waveguide is quite available for IC antenna of next-generation tokamaks. (author)

  12. PBG based terahertz antenna for aerospace applications

    CERN Document Server

    Choudhury, Balamati; Jha, Rakesh Mohan

    2016-01-01

    This book focuses on high-gain antennas in the terahertz spectrum and their optimization. The terahertz spectrum is an unallocated EM spectrum, which is being explored for a number of applications, especially to meet increasing demands of high data rates for wireless space communications. Space communication systems using the terahertz spectrum can resolve the problems of limited bandwidth of present wireless communications without radio-frequency interference. This book describes design of such high-gain antennas and their performance enhancement using photonic band gap (PBG) substrates. Further, optimization of antenna models using evolutionary algorithm based computational engine has been included. The optimized high-performance compact antenna may be used for various wireless applications, such as inter-orbital communications and on-vehicle satellite communications.

  13. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  14. Hybrid Methods in Designing Sierpinski Gasket Antennas

    Directory of Open Access Journals (Sweden)

    Mudrik Alaydrus

    2010-12-01

    Full Text Available Sierpinki gasket antennas as example of fractal antennas show multiband characteristics. The computer simulation of Sierpinksi gasket monopole with finite ground needs prohibitively large computer memory and more computational time. Hybrid methods consist of surface integral equation method and physical optics or uniform geometrical theory of diffraction should alleviate this computational burdens. The so-called full hybridization of the different methods with modifying the incoming electromagnetic waves in case of hybrid method surface integral equation method and physical optics and modification of the Greens function for hybrid method surface integral equation method and uniform geometrical theory of diffraction plays the central role in the observation. Comparison between results of different methods are given and also measurements of three Sierpinksi gasket antennas. The multiband characteristics of the antennas still can be seen with some reduction and enhancement of resonances.

  15. Resonant-bar gravitational radiation antennas

    International Nuclear Information System (INIS)

    Blair, D.G.

    1987-01-01

    This paper reviews the concept of gravitational radiation, and describes the worldwide research programme for the development of high-sensitivity resonant-bar antennas which are aimed at detecting gravitational radiation from astrophysical sources. (author)

  16. Focused Application Software for Ferrite Patch Antennas

    National Research Council Canada - National Science Library

    Trott, Keith

    1999-01-01

    ... (brick and tetrahedral elements) are combined by MRC via a graphical user interface (GUI) into a user friendly code capable of modeling conformal antennas with ferrite sub and superstrates recessed in planar surfaces.

  17. Radiation Pattern of Chair Armed Microstrip Antenna

    Science.gov (United States)

    Mishra, Rabindra Kishore; Sahu, Kumar Satyabrat

    2016-12-01

    This work analyzes planar antenna conformable to chair arm shaped surfaces for WLAN application. Closed form expressions for its radiation pattern are developed and validated using measurements on prototype and commercial EM code at 2.4 GHz.

  18. Compact, Frequency Reconfigurable, Printed Monopole Antenna

    Directory of Open Access Journals (Sweden)

    Ricardo Gonçalves

    2012-01-01

    Full Text Available This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results.

  19. Resonance spectra of diabolo optical antenna arrays

    Directory of Open Access Journals (Sweden)

    Hong Guo

    2015-10-01

    Full Text Available A complete set of diabolo optical antenna arrays with different waist widths and periods was fabricated on a sapphire substrate by using a standard e-beam lithography and lift-off process. Fabricated diabolo optical antenna arrays were characterized by measuring the transmittance and reflectance with a microscope-coupled FTIR spectrometer. It was found experimentally that reducing the waist width significantly shifts the resonance to longer wavelength and narrowing the waist of the antennas is more effective than increasing the period of the array for tuning the resonance wavelength. Also it is found that the magnetic field enhancement near the antenna waist is correlated to the shift of the resonance wavelength.

  20. Heating profiles on ICRF antenna Faraday shields

    International Nuclear Information System (INIS)

    Taylor, D.J.; Baity, F.W.; Hahs, C.L.; Riemer, B.W.; Ryan, P.M.; Williamson, D.E.

    1991-01-01

    A conceptual design for an uncooled Faraday shield for the BPX ion cyclotron resonance heating (ICRH) antenna, which should withstand the proposed long-pulse operation, has been completed. A high-heat-flux, uncooled Faraday shield has also been designed for the fast-wave current drive (FWCD) antenna on D3-D. For both components, the improved understanding of the heating profiles made it possible to design for heat fluxes that would otherwise have been too close to mechanically established limits. The analytical effort is described in detail, with emphasis on the design work for the BPX ICRH antenna conceptual design and for the replacement Faraday shield for the D3-D FWCD antenna. Results of analyses are shown, and configuration issues involved in component modeling are discussed. 3 refs., 6 figs., 2 tabs

  1. Deep Space Network Antenna Logic Controller

    Science.gov (United States)

    Ahlstrom, Harlow; Morgan, Scott; Hames, Peter; Strain, Martha; Owen, Christopher; Shimizu, Kenneth; Wilson, Karen; Shaller, David; Doktomomtaz, Said; Leung, Patrick

    2007-01-01

    The Antenna Logic Controller (ALC) software controls and monitors the motion control equipment of the 4,000-metric-ton structure of the Deep Space Network 70-meter antenna. This program coordinates the control of 42 hydraulic pumps, while monitoring several interlocks for personnel and equipment safety. Remote operation of the ALC runs via the Antenna Monitor & Control (AMC) computer, which orchestrates the tracking functions of the entire antenna. This software provides a graphical user interface for local control, monitoring, and identification of faults as well as, at a high level, providing for the digital control of the axis brakes so that the servo of the AMC may control the motion of the antenna. Specific functions of the ALC also include routines for startup in cold weather, controlled shutdown for both normal and fault situations, and pump switching on failure. The increased monitoring, the ability to trend key performance characteristics, the improved fault detection and recovery, the centralization of all control at a single panel, and the simplification of the user interface have all reduced the required workforce to run 70-meter antennas. The ALC also increases the antenna availability by reducing the time required to start up the antenna, to diagnose faults, and by providing additional insight into the performance of key parameters that aid in preventive maintenance to avoid key element failure. The ALC User Display (AUD) is a graphical user interface with hierarchical display structure, which provides high-level status information to the operation of the ALC, as well as detailed information for virtually all aspects of the ALC via drill-down displays. The operational status of an item, be it a function or assembly, is shown in the higher-level display. By pressing the item on the display screen, a new screen opens to show more detail of the function/assembly. Navigation tools and the map button allow immediate access to all screens.

  2. Designing a fractal antenna of 2400 MHz

    International Nuclear Information System (INIS)

    Miranda Hamburger, Fabio

    2012-01-01

    The design of a fractal antenna with 2400 MHz of frequency has been studied. The fractal used is described by Waclaw Spierpi.ski. The initial figure, also known as seed, is divided using equilateral triangles with the aim of obtaining a perimeter similar to a meaningful portion of wave length. The use of λ to establish an ideal perimeter has reduced the radiation resistance. The adequate number of iterations needed to design the antenna is calculated based on λ. (author) [es

  3. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  4. Time-Zone-Pattern Satellite Broadcasting Antenna

    Science.gov (United States)

    Galindo, Victor; Rahmat-Samii, Yahya; Imbriale, William A.; Cohen, Herb; Cagnon, Ronald R.

    1988-01-01

    Direct-broadcast satellite antenna designs provide contoured beams to match four time zones in 48 contiguous states and spot beams for Alaska, Hawaii, and Puerto Rico presented in 29-page report. Includes descriptions of procedures used to arrive at optimized designs. Arrangements, amplitudes, and phases of antenna feeds presented in tables. Gain contours shown graphically. Additional tables of performance data given for cities in service area of Eastern satellite.

  5. A note on antennas: Definitions and methods

    DEFF Research Database (Denmark)

    Bach, Henning

    1987-01-01

    Definitions of scattered and diffracted fields, originally given by R. F. Millar, are reviewed and supplemented. The definitions are used to discuss relations between results obtained by commonly used pattern prediction methods for reflector antennas.......Definitions of scattered and diffracted fields, originally given by R. F. Millar, are reviewed and supplemented. The definitions are used to discuss relations between results obtained by commonly used pattern prediction methods for reflector antennas....

  6. International Conference on Antenna Theory and Techniques

    Science.gov (United States)

    1999-12-03

    Krüger, Introduction to Solar radio astronomy and radio physics.- D.Reidel publishing company. Dordrecht: Hol- land/Boston: USA. London: England. 1982...REFERENCES 1. M. S. Juk, J. B. Molochkov Designing lens, scan- ning, broadband of antennae and feeder devices. - Moscow: Energia , 1973. - 440 p...system of this antenna was exe- cuted. Besides the thermal deformations of a mirror caused by daytime solar heating were investigated as well as

  7. Magneto-Electric Dipole Antenna Arrays

    OpenAIRE

    Gupta, Shulabh; Jiang, Li Jun; Caloz, Christophe

    2014-01-01

    A planar magneto-electric (ME) dipole antenna array is proposed and demonstrated by both full-wave analysis and experiments. The proposed structure leverages the infinite wavelength propagation characteristic of composite right/left-handed (CRLH) transmission lines to form high-gain magnetic radiators combined with radial conventional electric radiators, where the overall structure is excited by a single differential feed. The traveling-wave type nature of the proposed ME-dipole antenna enabl...

  8. Helicon plasma with additional immersed antenna

    International Nuclear Information System (INIS)

    Aanesland, A; Charles, C; Boswell, R W; Fredriksen, A

    2004-01-01

    A 'primary' RF power (H-power) at 13.56 MHz is coupled to a plasma source excited by an external double saddle field Helicon antenna. A 'secondary' RF power (S-power), also at 13.56 MHz but with variable phase, is additionally coupled by inserting a second antenna in contact with the plasma through one end of the source. The immersed antenna can be grounded or floating, allowing a self-bias to form in the latter case. Changes in the plasma density and electron temperature are measured in both cases with varying power on the immersed antenna. The plasma potential increases dramatically with S-power in the grounded case, and is found to be similar in size to the sum of the plasma potential and the self-bias formed in the floating case for all powers. Hence, the sheath between the immersed antenna and the plasma is shown to be equal in both the grounded and floating cases. Although the power efficiency does not vary significantly as a function of the S-power, it is consistently lower for the grounded case possibly as a result of a dc current to ground. The plasma parameters are drastically changed as the phase between the two antennae are varied (floating case), and a sinusoidal function was fitted to the plasma parameters as a function of the phase shift. The calculated power loss to the antenna indicates that the power efficiency of the immersed antenna, as the phase is changed, is altered from 80% to 10%

  9. Collision effects on propagation characteristics of electromagnetic waves in a sub-wavelength plasma slab of partially ionized dense plasmas

    Science.gov (United States)

    Bowen, LI; Zhibin, WANG; Qiuyue, NIE; Xiaogang, WANG; Fanrong, KONG; Zhenyu, WANG

    2018-01-01

    Intensive collisions between electrons and neutral particles in partially ionized plasmas generated in atmospheric/sub-atmospheric pressure environments can sufficiently affect the propagation characteristics of electromagnetic waves, particularly in the sub-wavelength regime. To investigate the collisional effect in such plasmas, we introduce a simplified plasma slab model with a thickness on the order of the wavelength of the incident electromagnetic wave. The scattering matrix method (SMM) is applied to solve the wave equation in the plasma slab with significant nonuniformity. Results show that the collisions between the electrons and the neutral particles, as well as the incident angle and the plasma thickness, can disturb the transmission and reduce reflection significantly.

  10. Resonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer films

    Science.gov (United States)

    Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

    2006-02-01

    We observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The "anomalous transmission" spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the `anomalous transmission' peaks are broader in the exotic metallic PPy (PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, showing that the surface plasmon polaritons on the PPy (PF6) film surfaces have higher attenuation.

  11. SPP-assisted sub-wavelength reflection-type THz imaging with THz time-domain spectrometer

    Science.gov (United States)

    Lai, Senfeng; Wu, Yanghui; Wu, Wen; Gu, Wenhua

    2017-08-01

    THz imaging has become a hot research topic in recent years, thanks to its merits of non-contact, strong penetration, immunity to hostile environments, and nondestructive detection. However, its spatial resolution is limited by the relatively long wavelength, so the location and measurement precision can only reach the level of the imaging wavelength, which has become a severe limitation of THz imaging. A simple way using surface plasmonic polartons (SPPs) to improve the location and measurement precision of THz by one order of magnitude was proposed in this manuscript, which can realize subwavelength THz imaging.

  12. Ab initio analytical model of light transmission through a cylindrical subwavelength hole in an optically thick film

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    2011-01-01

    The rigorous analytical theory of light transmission through a cylindrical hole of arbitrary diameter in an optically thick film is developed. The approach is based on the introduction of fictitious surface currents at both hole openings and both film surfaces. The solution of Maxwell’s equations...... the film thickness considerably exceeds the hole diameter. It is emphasized that a specific pole corresponding to excitation of surface plasmon polaritons does not appear in the analysis. The theory is illustrated by the calculation of light transmission through a subwavelength hole in an Ag film....

  13. An Overview of Antenna R&D Efforts in Support of NASA's Space Exploration Vision

    Science.gov (United States)

    Manning, Robert M.

    2007-01-01

    This presentation reviews the research and development work being conducted at Glenn Research Center in the area of antennas for space exploration. In particular, after reviewing the related goals of the agency, antenna technology development at GRC is discussed. The antennas to be presented are large aperture inflatable antennas, phased array antennas, a 256 element Ka-band antenna, a ferroelectric reflectarray antenna, multibeam antennas, and several small antennas.

  14. Printing of Wearable Antenna on Textile

    Directory of Open Access Journals (Sweden)

    Khirotdin Rd. Khairilhijra

    2018-01-01

    Full Text Available A wearable antenna which is meant to be a part of the clothing used for communication purposes includes tracking, navigation and mobile computing has been seen in demand due to the recent miniaturization of wireless devices. Printing of conductive ink provides flexibility properties on electronics thus allowing it to be used on conformal surfaces. However, the current printing techniques mostly suffer from ink incompatibility and limited of substrates to be printed with. Hence, this paper intend to discloses the printing of wearable antenna using alternative technique via syringe-based deposition system with conductive ink on textile. A validation between simulation and measurement of return loss, (S11 and radiation pattern of the antenna printed is also performed. It was found that a functional antenna is successfully printed on textile since the performances obtained are as expected. The antenna resonated at a minimum resonant frequency of 1.82 GHz which the S11 gathered at-18.90 dB. The radiation pattern for both simulation and measurement is as predicted since both have a larger magnitude of the main lobe than the side lobe. The magnitude of the main lobe from measurement was observed to be 8.83 dB higher than the magnitude of the main lobe of the simulation which is only 3.77 dB. It is proven that the syringe-based deposition system is capable of printing functional antenna on textile.

  15. Compact super-wideband optical antenna

    Science.gov (United States)

    Wang, Wen C.; Forber, Richard; Bui, Kenneth

    2009-05-01

    We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

  16. Antenna development for astroparticle and radioastronomy experiments

    International Nuclear Information System (INIS)

    Charrier, Didier

    2012-01-01

    An active dipole antenna is in operation since five years at the Nançay radio Observatory (France) in the CODALEMA experiment. A new version of this active antenna has been developed, whose shape gave its name of “Butterfly” antenna. Compared to the previous version, this new antenna has been designed to be more efficient at low frequencies, which could permit the detection of atmospheric showers at large distances. Despite a size of only 2 m×1 m in each polarization, its sensitivity is excellent in the 30-80 MHz bandwidth. Three antennas in dual polarization were installed on the CODALEMA experiment, and four other have been recently installed on the Auger area in the scope of the AERA project. The main characteristics of the Butterfly antenna are detailed with an emphasis on its key features which make it a good candidate for the low frequency radioastronomy and the radio detection of transients induced by high energy cosmic rays.

  17. Three-dimensional analysis of antenna sheaths

    International Nuclear Information System (INIS)

    Myra, J.R.; D'Ippolito, D.A.; Ho, Y.L.

    1996-01-01

    The present work is motivated by the importance of r.f. sheaths in determining the antenna-plasma interaction and the sensitivity of the sheaths to the complicated three-dimensional structure of modern ion cyclotron range of frequency (ICRF) antennas. To analyze r.f. sheaths on the plasma facing regions of the launcher, we first calculate the contact points of the tokamak magnetic field lines on the surface of the antenna Faraday screen and nearby limiters for realistic three-dimensional magnetic flux surface and antenna geometries. Next, the r.f. voltage that can drive sheaths at the contact points is determined and used to assess the resulting sheath power dissipation, r.f.-driven sputtering, and r.f.-induced convective cells (which produce edge profile modification). The calculations are embodied in a computer code, ANSAT (antenna sheath analysis tool), and sample ANSAT runs are shown to highlight the physics- and geometry-dependent characteristics of the r.f. sheaths and their relationship to the antenna design. One use of ANSAT is therefore as a design tool, to assess the strengths and weaknesses of a given design with respect to critical voltage handling and edge plasma interaction issues. Additionally, examples are presented where ANSAT has been useful in the analysis and interpretation of ICRF experiments (orig.)

  18. Antireflective sub-wavelength structures for improvement of the extraction efficiency and color rendering index of monolithic white light-emitting diode

    DEFF Research Database (Denmark)

    Ou, Yiyu; Corell, Dennis Dan; Dam-Hansen, Carsten

    2011-01-01

    We have theoretically investigated the influence of antireflective sub-wavelength structures on a monolithic white light-emitting diode (LED). The simulation is based on the rigorous coupled wave analysis (RCWA) algorithm, and both cylinder and moth-eye structures have been studied in the work. Our...... simulation results show that a moth-eye structure enhances the light extraction efficiency over the entire visible light range with an extraction efficiency enhancement of up to 26 %. Also for the first time to our best knowledge, the influence of sub-wavelength structures on both the color rendering index...

  19. One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

    Science.gov (United States)

    Lin, Yo-Sheng; Hu, Chun-Hao; Chang, Chi-Ho; Tsao, Ping-Chang

    2018-06-01

    In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.

  20. Performance Enhancement of the Patch Antennas Applying Micromachining Technology

    Directory of Open Access Journals (Sweden)

    Mohamed N. Azermanesh

    2007-09-01

    Full Text Available This paper reports on the application of micromachining technology for performance enhancement of two types of compact antennas which are becoming a common practice in microsystems. Shorted patch antennas (SPA and folded shorted patch antennas operating in the 5-6 GHz ISM band, with intended application in short-range wireless communications, are considered. The electrical length of antennas are modified by etching the substrate of the antennas, thus providing a new degree of freedom to control the antenna operating properties, which is the main novelty of our work. The gain and bandwidth of the antennas are increased by increasing the etching depth. However, etching the substrate affects the operating frequency as well. To keep the operating frequency at a pre-specified value, the dimension of the antennas must be increased by deepening the etching depth. Therefore, a trade off between the performance enhancement of the antennas and the dimensional enlargement is required.

  1. Analysis of equivalent antenna based on FDTD method

    Directory of Open Access Journals (Sweden)

    Yun-xing Yang

    2014-09-01

    Full Text Available An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is airtakes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

  2. Characteristics of the wire biconical antenna used for EMC measurements

    Science.gov (United States)

    Austin, Brian A.; Fourie, Andre P. C.

    1991-08-01

    The characteristics of a wire biconical antenna that determine its antenna factor were computed by using the method of moments code NEC-2. A fairly extensive validation exercise was conducted from which a suitable computer model was derived. The input impedance, gain, and radiation patterns of the antenna were computed for special cases where the biconical antenna is used above a conducting ground plane for open-field EMC (electromagnetic compatibility) testing. The effects of height above the ground plane and polarization of the antenna on these parameters were found and the antenna factor was corrected for them. The current distribution along the antenna elements was also examined, and it was found that significant pattern distortion can occur at some frequencies when a horizontal wire biconical antenna is used close to the ground. These results will allow this broadband antenna to be used with confidence in applications where previously only resonant dipoles were specified.

  3. Performance Verification on UWB Antennas for Breast Cancer Detection

    Directory of Open Access Journals (Sweden)

    Vijayasarveswari V.

    2017-01-01

    Full Text Available Breast cancer is a common disease among women and death figure is continuing to increase. Early breast cancer detection is very important. Ultra wide-band (UWB is the promising candidate for short communication applications. This paper presents the performance of different types of UWB antennas for breast cancer detection. Two types of antennas are used i.e: UWB pyramidal antenna and UWB horn antenna. These antennas are used to transmit and receive the UWB signal. The collected signals are fed into developed neural network module to measure the performance efficiency of each antenna. The average detection efficiency is 88.46% and 87.55% for UWB pyramidal antenna and UWB horn antenna respectively. These antennas can be used to detect breast cancer in the early stage and save precious lives.

  4. Superconducting microstrip antennas: An experimental comparison of two feeding methods

    International Nuclear Information System (INIS)

    Richard, M.A.; Claspy, P.C.; Bhasin, K.B.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTS's) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. In this paper, two methods for feeding HTS microstrip antennas at K and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals

  5. 60 GHz Antenna Diagnostics from Planar Near Field Antenna Measurement Without External Frequency Conversion

    DEFF Research Database (Denmark)

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

    2015-01-01

    ,J.M. Nielsen, O. Breinbjerg, 60 GHz Antenna Measurement Setup using a VNA without External Frequency Conversion,36th Annual Symposium of the Antenna Measurement Technique Association ,October 12-17,Tucson, Arizona, 2014]. In this work we extend the validation of this 60 GHz planar near-field (PNF) set...

  6. Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper

    2015-01-01

    and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...

  7. Pulsed energy storage antennas for ionospheric modification

    Directory of Open Access Journals (Sweden)

    R. F. Wuerker

    2005-01-01

    Full Text Available Interesting, "new", very high peak-power pulsed radio frequency (RF antennas have been assembled at the HIPAS Observatory (Alaska, USA and also at the University of California at Los Angeles (UCLA, USA; namely, a pair of quarter wavelength (λ/4 long cylindrical conductors separated by a high voltage spark gap. Such a combination can radiate multi-megawatt RF pulses whenever the spark gap fires. The antenna at HIPAS is 53m long (λ/2 with a central pressurized SF6 spark gap. It is mounted 5 meters (λ/21 above a ground plane. It radiates at 2.85MHz. The two antenna halves are charged to ± high voltages by a Tesla coil. Spark gap voltages of 0.4 MV (at the instant of spark gap closure give peak RF currents of ~1200A which correspond to ~14 MW peak total radiated power, or ~56 MW of Effective Radiated Power (ERP. The RF pulse train is initially square, decaying exponentially in time with Qs of ~50. Two similar but smaller 80-MHz antennas were assembled at UCLA to demonstrate their synchronization with a pulsed laser which fired the spark gaps in the two antennas simultanoeously. These experiments show that one can anticipate a pulsed array of laser synchronized antennas having a coherent Effective Radiated Power (ERP>10GW. One can even reconsider a pulse array radiating at 1.43MHz which corresponds to the electron gyrofrequency in the Earth's magnetic field at ~200km altitude. These "new" pulsed high power antennas are hauntingly similar to the ones used originally by Hertz (1857-1894 during his (1886-1889 seminal verifications of Maxwell's (1864 theory of electrodynamics.

  8. Pulsed energy storage antennas for ionospheric modification

    Directory of Open Access Journals (Sweden)

    R. F. Wuerker

    2005-01-01

    Full Text Available Interesting, "new", very high peak-power pulsed radio frequency (RF antennas have been assembled at the HIPAS Observatory (Alaska, USA and also at the University of California at Los Angeles (UCLA, USA; namely, a pair of quarter wavelength (λ/4 long cylindrical conductors separated by a high voltage spark gap. Such a combination can radiate multi-megawatt RF pulses whenever the spark gap fires. The antenna at HIPAS is 53m long (λ/2 with a central pressurized SF6 spark gap. It is mounted 5 meters (λ/21 above a ground plane. It radiates at 2.85MHz. The two antenna halves are charged to ± high voltages by a Tesla coil. Spark gap voltages of 0.4 MV (at the instant of spark gap closure give peak RF currents of ~1200A which correspond to ~14 MW peak total radiated power, or ~56 MW of Effective Radiated Power (ERP. The RF pulse train is initially square, decaying exponentially in time with Qs of ~50. Two similar but smaller 80-MHz antennas were assembled at UCLA to demonstrate their synchronization with a pulsed laser which fired the spark gaps in the two antennas simultanoeously. These experiments show that one can anticipate a pulsed array of laser synchronized antennas having a coherent Effective Radiated Power (ERP>10GW. One can even reconsider a pulse array radiating at 1.43MHz which corresponds to the electron gyrofrequency in the Earth's magnetic field at ~200km altitude. These "new" pulsed high power antennas are hauntingly similar to the ones used originally by Hertz (1857-1894 during his (1886-1889 seminal verifications of Maxwell's (1864 theory of electrodynamics.

  9. Injection and waveguiding properties in SU8 nanotubes for sub-wavelength regime propagation and nanophotonics integration

    Science.gov (United States)

    Bigeon, John; Huby, Nolwenn; Duvail, Jean-Luc; Bêche, Bruno

    2014-04-01

    We report photonic concepts related to injection and sub-wavelength propagation in nanotubes, an unusual but promising geometry for highly integrated photonic devices. Theoretical simulation by the finite domain time-dependent (FDTD) method was first used to determine the features of the direct light injection and sub-wavelength propagation regime within nanotubes. Then, the injection into nanotubes of SU8, a photoresist used for integrated photonics, was successfully achieved by using polymer microlensed fibers with a sub-micronic radius of curvature, as theoretically expected from FDTD simulations. The propagation losses in a single SU8 nanotube were determined by using a comprehensive set-up and a protocol for optical characterization. The attenuation coefficient has been evaluated at 1.25 dB mm-1 by a cut-back method transposed to such nanostructures. The mechanisms responsible for losses in nanotubes were identified with FDTD theoretical support. Both injection and cut-back methods developed here are compatible with any sub-micronic structures. This work on SU8 nanotubes suggests broader perspectives for future nanophotonics.

  10. U Patch Antenna for RFID and Wireless Applications

    International Nuclear Information System (INIS)

    Abi Saad, R.; Melhem, Z.; Nader, C.; Zaatar, Y.; Zaouk, D.

    2011-01-01

    in this paper, we propose a new multi-band patch antenna structure for embedded RFID (Radio Frequency Identification) readers and wireless communications. The proposed antenna is a dual band microstrip patch antenna using U-slot geometry. The operating frequencies of the proposed antenna are chosen as 2.4 and 0.9 (GHz), obtained by optimizing the physical dimensions of the U-slot. Several parameters have been investigated using Ansoft Designer software. The antenna is fed through a quarter wavelength transformer for impedance matching. An additional layer of alumina is added above the surface of the conductors to increase the performance of the antenna. (author)

  11. Curtain Antenna Array Simulation Research Based on MATLAB

    Directory of Open Access Journals (Sweden)

    Hongbo LIU

    2014-01-01

    Full Text Available For the radiating capacity of curtain antenna array, this paper constructs a three- line-four-column curtain antenna array using cage antenna as the antenna array element and obtains a normalizing 3D radiation patterns through conducting simulation with MATLAB. Meanwhile, the relationships between the antenna spacing and the largest directivity coefficient, as well as the communication frequency and largest directivity coefficient are analyzed in this paper. It turns out that the max value will generate when the antenna spacing is around 18 m and the best communication effect will be achieved when the communication frequency is about 12.4 MHz.

  12. A Modal Approach to Compact MIMO Antenna Design

    Science.gov (United States)

    Yang, Binbin

    MIMO (Multiple-Input Multiple-Output) technology offers new possibilities for wireless communication through transmission over multiple spatial channels, and enables linear increases in spectral efficiency as the number of the transmitting and receiving antennas increases. However, the physical implementation of such systems in compact devices encounters many physical constraints mainly from the design of multi-antennas. First, an antenna's bandwidth decreases dramatically as its electrical size reduces, a fact known as antenna Q limit; secondly, multiple antennas closely spaced tend to couple with each other, undermining MIMO performance. Though different MIMO antenna designs have been proposed in the literature, there is still a lack of a systematic design methodology and knowledge of performance limits. In this dissertation, we employ characteristic mode theory (CMT) as a powerful tool for MIMO antenna analysis and design. CMT allows us to examine each physical mode of the antenna aperture, and to access its many physical parameters without even exciting the antenna. For the first time, we propose efficient circuit models for MIMO antennas of arbitrary geometry using this modal decomposition technique. Those circuit models demonstrate the powerful physical insight of CMT for MIMO antenna modeling, and simplify MIMO antenna design problem to just the design of specific antenna structural modes and a modal feed network, making possible the separate design of antenna aperture and feeds. We therefore develop a feed-independent shape synthesis technique for optimization of broadband multi-mode apertures. Combining the shape synthesis and circuit modeling techniques for MIMO antennas, we propose a shape-first feed-next design methodology for MIMO antennas, and designed and fabricated two planar MIMO antennas, each occupying an aperture much smaller than the regular size of lambda/2 x lambda/2. Facilitated by the newly developed source formulation for antenna stored

  13. Numerical Simulation of Plasma Antenna with FDTD Method

    International Nuclear Information System (INIS)

    Chao, Liang; Yue-Min, Xu; Zhi-Jiang, Wang

    2008-01-01

    We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconBgurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design

  14. Numerical simulation of plasma antenna with FDTD method

    International Nuclear Information System (INIS)

    Liang Chao; Xu Yuemin; Wang Zhijiang

    2008-01-01

    We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconfigurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design. (authors)

  15. Inkjet-Printed Ultra Wide Band Fractal Antennas

    KAUST Repository

    Maza, Armando Rodriguez

    2012-05-01

    In this work, Paper-based inkjet-printed Ultra-wide band (UWB) fractal antennas are presented. Three new designs, a combined UWB fractal monopole based on the fourth order Koch Snowflake fractal which utilizes a Sierpinski Gasket fractal for ink reduction, a Cantor-based fractal antenna which performs a larger bandwidth compared to previously published UWB Cantor fractal monopole antenna, and a 3D loop fractal antenna which attains miniaturization, impedance matching and multiband characteristics. It is shown that fractals prove to be a successful method of reducing fabrication cost in inkjet printed antennas while retaining or enhancing printed antenna performance.

  16. High efficiency carbon nanotube thread antennas

    Science.gov (United States)

    Amram Bengio, E.; Senic, Damir; Taylor, Lauren W.; Tsentalovich, Dmitri E.; Chen, Peiyu; Holloway, Christopher L.; Babakhani, Aydin; Long, Christian J.; Novotny, David R.; Booth, James C.; Orloff, Nathan D.; Pasquali, Matteo

    2017-10-01

    Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These measurements are crucial for any practical application of CNT materials in wireless communication. In this letter, we report a measurement technique to accurately characterize the radiation efficiency of λ/4 monopole antennas made from the CNT thread. We measure the highest absolute values of radiation efficiency for CNT antennas of any type, matching that of copper wire. To capture the weight savings, we propose a specific radiation efficiency metric and show that these CNT antennas exceed copper's performance by over an order of magnitude at 1 GHz and 2.4 GHz. We also report direct experimental observation that, contrary to metals, the radiation efficiency of the CNT thread improves significantly at higher frequencies. These results pave the way for practical applications of CNT thread antennas, particularly in the aerospace and wearable electronics industries where weight saving is a priority.

  17. A Novel Compact Dual-Polarized Antenna

    Directory of Open Access Journals (Sweden)

    Yong Cheng

    2016-01-01

    Full Text Available A novel compact dual-polarized antenna is proposed. The antenna has a 1.43% impedance bandwidth which is from 1801 MHz to 1827 MHz for return loss larger than 10 dB. The isolation between the two ports is above 28 dB in the bandwidth, and the gain is 6.6 dBi. The proposed antenna not only consists of a full-planar structure, but also is easy to be fabricated for its simple structure. Additionally, a section of slots and slits is cut on the radiation patch to reduce the area of it to 54% compared with the conventional square patch.

  18. Recent developments in ICRF antenna modelling

    International Nuclear Information System (INIS)

    Lamalle, P.U.; Messiaen, A.M.; Dumortier, P.; Louche, F.

    2005-01-01

    The antennas presently developed for ICRF heating of the ITER plasma consist of a tightly packed array of a large number of radiating straps, in order to deliver a high power density without exceeding radio-frequency voltage standoffs. Recently developed commercial software has enabled important progress in the coupling analysis and optimisation of such demanding systems. Approximations allowing to convincingly include a realistic plasma description in these codes are discussed. Application of the resulting numerical tools is illustrated by simulation of the existing JET A2 ICRF array, with the goal to validate simulations for future antennas. Advances in the design of realistic test bed conditions, using salted water as a means of creating plasma-relevant antenna loading, and the appropriate scaling of a mockup are also presented. (author)

  19. Sensitivity of a combined gravitational antenna

    International Nuclear Information System (INIS)

    Kulagin, V.V.; Rudenko, V.N.

    1986-01-01

    A modification of a combined optico-acoustic gravitational antenna: a long-base laser interferometer, where free masses are changed by Weber resonators, is suggested. The combined gravitational antenna can possess sensitivity h min ∼ 10 -18 without deep cooling of Weber resonators and h min ∼ 10 -19 at helium temperaure of the resonators. This antenna has the following new quantities: presence of three independent responses, that permits to a considerable extent to exclude non-gravitational effects; presence of responses of two separated Weber resonators, that permits to register the wave character of gravitational perturbation by measuring phase shift between relaxation ''tails''. It means that one may with certainty register the wave structure of gravitational radiation for perturbation of metrics h, exceeding the threshold sensitivity of the known detectors by an order

  20. Statistical monitoring of linear antenna arrays

    KAUST Repository

    Harrou, Fouzi

    2016-11-03

    The paper concerns the problem of monitoring linear antenna arrays using the generalized likelihood ratio (GLR) test. When an abnormal event (fault) affects an array of antenna elements, the radiation pattern changes and significant deviation from the desired design performance specifications can resulted. In this paper, the detection of faults is addressed from a statistical point of view as a fault detection problem. Specifically, a statistical method rested on the GLR principle is used to detect potential faults in linear arrays. To assess the strength of the GLR-based monitoring scheme, three case studies involving different types of faults were performed. Simulation results clearly shown the effectiveness of the GLR-based fault-detection method to monitor the performance of linear antenna arrays.

  1. Terahertz antenna technology for space applications

    CERN Document Server

    Choudhury, Balamati; Jha, Rakesh Mohan

    2016-01-01

    This book explores the terahertz antenna technology towards implementation of compact, consistent and cheap terahertz sources, as well as the high sensitivity terahertz detectors. The terahertz EM band provides a transition between the electronic and the photonic regions thus adopting important characteristics from these regimes. These characteristics, along with the progress in semiconductor technology, have enabled researchers to exploit hitherto unexplored domains including satellite communication, bio-medical imaging, and security systems. The advances in new materials and nanostructures such as graphene will be helpful in miniaturization of antenna technology while simultaneously maintaining the desired output levels. Terahertz antenna characterization of bandwidth, impedance, polarization, etc. has not yet been methodically structured and it continues to be a major research challenge. This book addresses these issues besides including the advances of terahertz technology in space applications worldwide,...

  2. A Two Element Plasma Antenna Array

    Directory of Open Access Journals (Sweden)

    F. Sadeghikia

    2013-10-01

    Full Text Available This theoretical study presents the characteristics of plasma monopole antennas in the VHF/UHF range using finite difference time domain (FDTD simulation. Results show that more broadband characteristics can be obtained by increasing the diameter of the plasma tube and that the minor lobes diminish in intensity as diameter increases. Furthermore, the nulls are replaced by low level radiation. Since the collision frequency, which is a function of gas pressure, represents the loss mechanism of plasma, decreasing its value increases the gain and radar cross section (RCS of the antenna. Theoretical modeling shows that at higher plasma frequencies with respect to the signal frequency, the gain and radar cross section of the plasma antenna are high enough and that the impedance curves are altered as the plasma frequency varies. Using these preliminary studies, mutual impedance and gain of a broadside array of two parallel side-by-side plasma elements is presented.

  3. High Gain Antenna Calibration on Three Spacecraft

    Science.gov (United States)

    Hashmall, Joseph A.

    2011-01-01

    This paper describes the alignment calibration of spacecraft High Gain Antennas (HGAs) for three missions. For two of the missions (the Lunar Reconnaissance Orbiter and the Solar Dynamics Observatory) the calibration was performed on orbit. For the third mission (the Global Precipitation Measurement core satellite) ground simulation of the calibration was performed in a calibration feasibility study. These three satellites provide a range of calibration situations-Lunar orbit transmitting to a ground antenna for LRO, geosynchronous orbit transmitting to a ground antenna fer SDO, and low Earth orbit transmitting to TDRS satellites for GPM The calibration results depend strongly on the quality and quantity of calibration data. With insufficient data the calibration Junction may give erroneous solutions. Manual intervention in the calibration allowed reliable parameters to be generated for all three missions.

  4. The fate of the Antennae galaxies

    Science.gov (United States)

    Lahén, Natalia; Johansson, Peter H.; Rantala, Antti; Naab, Thorsten; Frigo, Matteo

    2018-04-01

    We present a high-resolution smoothed particle hydrodynamic simulation of the Antennae galaxies (NGC 4038/4039) and follow the evolution 3 Gyr beyond the final coalescence. The simulation includes metallicity-dependent cooling, star formation, and both stellar feedback and chemical enrichment. The simulated best-match Antennae reproduce well both the observed morphology and the off-nuclear starburst. We also produce for the first time a simulated two-dimensional (2D) metallicity map of the Antennae and find good agreement with the observed metallicity of off-nuclear stellar clusters; however, the nuclear metallicities are overproduced by ˜0.5 dex. Using the radiative transfer code SKIRT, we produce multiwavelength observations of both the Antennae and the merger remnant. The 1-Gyr-old remnant is well fitted with a Sérsic profile of n = 7.07, and with an r-band effective radius of re = 1.6 kpc and velocity dispersion of σe = 180 km s-1 the remnant is located on the Fundamental Plane of early-type galaxies (ETGs). The initially blue Antennae remnant evolves on to the red sequence after ˜2.5 Gyr of secular evolution. The remnant would be classified as a fast rotator, as the specific angular momentum evolves from λRe ≈ 0.11 to 0.14 during its evolution. The remnant shows ordered rotation and a double peaked maximum in the mean 2D line-of-sight velocity. These kinematical features are relatively common amongst local ETGs and we specifically identify three local ETGs (NGC 3226, NGC 3379, and NGC 4494) in the atlas3D sample, whose photometric and kinematic properties most resemble the Antennae remnant.

  5. Dual-polarized feed antenna apparatus and method of use

    Science.gov (United States)

    Sarehraz, Mohammed (Inventor); Buckle, Kenneth A. (Inventor); Stefanakos, Elias (Inventor); Weller, Thomas (Inventor); Goswami, D. Yogi (Inventor)

    2009-01-01

    An antenna apparatus and method for the interception of randomly polarized electromagnetic waves utilizing a dual polarized antenna which is excited through a cross-slot aperture using two well-isolated orthogonal feeds.

  6. Design and optimization of LTE 1800 MIMO antenna.

    Science.gov (United States)

    Wong, Huey Shin; Islam, Mohammad Tariqul; Kibria, Salehin

    2014-01-01

    A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.

  7. On Connectivity of Wireless Sensor Networks with Directional Antennas

    Directory of Open Access Journals (Sweden)

    Qiu Wang

    2017-01-01

    Full Text Available In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models.

  8. 47 CFR 73.6025 - Antenna system and station location.

    Science.gov (United States)

    2010-10-01

    ... RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6025 Antenna system and station... clearly the radiation characteristics of the antenna above and below the horizontal plane. In cases where...

  9. Non-foster matching of an RFID antenna

    KAUST Repository

    Mohamed Hassan Salem, Nedime Pelin; Niver, Edip

    2011-01-01

    Novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags are investigated in ultra-high frequency (UHF) band. A microstrip dipole antenna with or without

  10. 3D Inkjet Printed Helical Antenna with Integrated Lens

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2016-01-01

    The gain of an antenna can be enhanced through the integration of a lens, although this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, through a unique

  11. Planar Ultrawideband Antenna with Photonically Controlled Notched Bands

    Directory of Open Access Journals (Sweden)

    Drasko Draskovic

    2013-01-01

    Full Text Available A design of a planar microstrip-fed ultrawideband (UWB printed circular monopole antenna with optically controlled notched bands is presented. The proposed antenna is composed of a circular ultrawideband patch, with an etched T-shaped slot controlled by an integrated silicon switch. The slot modifies the frequency response of the antenna suppressing 3.5–5 GHz band when the switch is in open state. The optical switch is controlled by a low-power near-infrared (808 nm laser diode, which causes the change in the frequency response of the antenna generating a frequency notch. This solution could be expanded to include several notches in the antenna frequency response achieving a fully reconfigurable UWB antenna. The antenna could be remotely controlled at large distances using optical fiber. The prototype antenna has been fully characterized to verify these design concepts.

  12. Broadband antenna for ground penetrating radar application in soil

    Science.gov (United States)

    Shebalkova, LV; Markov, MA; Romodin, VB

    2018-03-01

    The scope of the article embraces the features of design of antennas and arrays for GPR, their type and parameters and the expediency of the application of the antenna arrays in various purpose location systems of GPR.

  13. Tri-band small monopole antenna based on SRR units

    Directory of Open Access Journals (Sweden)

    Gehan Shehata

    2015-12-01

    Full Text Available In this paper a novel design for a tri-band monopole antenna coupled with metamaterial units is introduced. The proposed antenna was designed to cover WiMAX (2.5, 3.5 and WLAN (5.2 bands. In our proposal, a coplanar waveguide (CPW fed circular-disk monopole antenna is coupled with three split ring resonator (SRR units which exist on its back side. In our design a monopole antenna and SRR units are designed first to resonate at 5.2 GHz and 2.5 GHz respectively. In addition, antenna is loaded with post to force resonance at 3.5 GHz. SRR units are used for 2.5 GHz resonance to miniaturize antenna size, and our proposed antenna considered an electrically small antenna (ESA at its first resonance frequency. Simulated and measured results exhibit a good agreement that validate our design.

  14. Combline antennas for launching traveling fast waves

    International Nuclear Information System (INIS)

    Moeller, C.P.; Gould, R.W.; Phelps, D.A.; Pinsker, R.I.

    1994-01-01

    The combline structure shows promise for launching traveling fast magnetosonic waves with adjustable n parallel (3 ≤ n parallel ≤ 6) for current drive. In this paper, the dispersion and damping properties of the combline antenna with and without a Faraday shield are given. The addition of a Faraday shield which eliminates the electrostatic coupling between current straps as well as between the straps and plasma offers the advantage of eliminating the need for the lumped capacitors which are otherwise required with this structure. The results of vacuum dispersion and damping measurements on a low power model antenna are also given. (author)

  15. Frequency-agile antennas for wireless communications

    CERN Document Server

    Petosa, Aldo

    2013-01-01

    Mobile data subscriptions are expected to more than double and mobile wireless traffic to increase by more than tenfold over the next few years. Proliferation of smart phones, tablets, and other portable devices are placing greater demands for services such as web browsing, global positioning, video streaming, and video telephony. Many of the proposed solutions to deal with these demands will have a significant impact on antenna designs. Antennas with frequency agility are considered a promising technology to help implement these new solutions.This book provides readers with a sense of the cap

  16. MEMS-Reconfigurable Metamaterials and Antenna Applications

    Directory of Open Access Journals (Sweden)

    Tomislav Debogovic

    2014-01-01

    Full Text Available This paper reviews some of our contributions to reconfigurable metamaterials, where dynamic control is enabled by microelectromechanical systems (MEMS technology. First, we show reconfigurable composite right-/left-handed transmission lines (CRLH-TLs having state of the art phase velocity variation and loss, thereby enabling efficient reconfigurable phase shifters and leaky-wave antennas (LWA. Second, we present very low loss metasurface designs with reconfigurable reflection properties, applicable in reflectarrays and partially reflective surface (PRS antennas. All the presented devices have been fabricated and experimentally validated. They operate in X- and Ku-bands.

  17. A Case Study on Distributed Antenna Systems

    DEFF Research Database (Denmark)

    Sørensen, Troels Bundgaard

    2007-01-01

    Passive distributed antenna systems (DASs) consisting of distributed feeder lines or single point antennas are now often installed in large office buildings where they provide efficient coverage throughout the building. More sophisticated DASs with intelligent reuse and the ability to adapt...... is described in terms of algorithms for power allocation and access port assignment, as well as algorithms for (dynamic) channel assignment. After an outline of simulation assumptions, system capacity comparisons are given between the adaptive DAS and a system with fixed channel and access port assignment...

  18. Antenna subset selection at multi-antenna relay with adaptive modulation

    KAUST Repository

    Choi, Seyeong; Hasna, Mazen Omar; Yang, Hongchuan; Alouini, Mohamed-Slim

    2011-01-01

    In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

  19. Antenna subset selection at multi-antenna relay with adaptive modulation

    KAUST Repository

    Choi, Seyeong

    2011-06-01

    In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

  20. Subwavelength engineered fiber-to-chip silicon-on-sapphire interconnects for mid-infrared applications (Conference Presentation)

    Science.gov (United States)

    Alonso-Ramos, Carlos; Han, Zhaohong; Le Roux, Xavier; Lin, Hongtao; Singh, Vivek; Lin, Pao Tai; Tan, Dawn; Cassan, Eric; Marris-Morini, Delphine; Vivien, Laurent; Wada, Kazumi; Hu, Juejun; Agarwal, Anuradha; Kimerling, Lionel C.

    2016-05-01

    The mid-Infrared wavelength range (2-20 µm), so-called fingerprint region, contains the very sharp vibrational and rotational resonances of many chemical and biological substances. Thereby, on-chip absorption-spectrometry-based sensors operating in the mid-Infrared (mid-IR) have the potential to perform high-precision, label-free, real-time detection of multiple target molecules within a single sensor, which makes them an ideal technology for the implementation of lab-on-a-chip devices. Benefiting from the great development realized in the telecom field, silicon photonics is poised to deliver ultra-compact efficient and cost-effective devices fabricated at mass scale. In addition, Si is transparent up to 8 µm wavelength, making it an ideal material for the implementation of high-performance mid-IR photonic circuits. The silicon-on-insulator (SOI) technology, typically used in telecom applications, relies on silicon dioxide as bottom insulator. Unfortunately, silicon dioxide absorbs light beyond 3.6 µm, limiting the usability range of the SOI platform for the mid-IR. Silicon-on-sapphire (SOS) has been proposed as an alternative solution that extends the operability region up to 6 µm (sapphire absorption), while providing a high-index contrast. In this context, surface grating couplers have been proved as an efficient means of injecting and extracting light from mid-IR SOS circuits that obviate the need of cleaving sapphire. However, grating couplers typically have a reduced bandwidth, compared with facet coupling solutions such as inverse or sub-wavelength tapers. This feature limits their feasibility for absorption spectroscopy applications that may require monitoring wide wavelength ranges. Interestingly, sub-wavelength engineering can be used to substantially improve grating coupler bandwidth, as demonstrated in devices operating at telecom wavelengths. Here, we report on the development of fiber-to-chip interconnects to ZrF4 optical fibers and integrated SOS

  1. Non-foster matching of an RFID antenna

    KAUST Repository

    Mohamed Hassan Salem, Nedime Pelin

    2011-07-01

    Novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags are investigated in ultra-high frequency (UHF) band. A microstrip dipole antenna with or without an integrated negative impedance converter designed to cancel out the antenna\\'s input capacitance at resonance frequency was designed, simulated, constructed and measured for implementation in RFID applications. © 2011 IEEE.

  2. Multiport antenna systems for space-time communications

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Alrabadi, Osama; Pelosi, Mauro

    2013-01-01

    The paper presents the concept of multiport antenna systems where multiple active and passive ports are deployed. The passive ports, implemented via tunable reactance-assisted (parasitic) antennas, can alter the far-field and near-field properties of the antenna system expressed by the antenna...... efficiency, electromagnetic coupling and spatial correlation. The system can be optimized in order to enhance the spatial multiplexing performance whereas the performance gains come at no significant additional cost and hardware complexity...

  3. Reconfigurable Patch Antenna Radiations Using Plasma Faraday Shield Effect

    OpenAIRE

    Barro , Oumar Alassane; Himdi , Mohamed; Lafond , Olivier

    2016-01-01

    International audience; This letter presents a new reconfigurable antenna associated with a plasma Faraday shield effect. The Faraday shield effect is realized by using a fluorescent lamp. A patch antenna operating at 2.45 GHz is placed inside the lamp. The performance of the reconfigurable system is observed in terms of S11, gain and radiation patterns by simulation and measurement. It is shown that by switching ON the fluorescent lamp, the gain of the antenna decreases and the antenna syste...

  4. Optimized dipole antennas on photonic band gap crystals

    International Nuclear Information System (INIS)

    Cheng, S.D.; Biswas, R.; Ozbay, E.; McCalmont, S.; Tuttle, G.; Ho, K.

    1995-01-01

    Photonic band gap crystals have been used as a perfectly reflecting substrate for planar dipole antennas in the 12--15 GHz regime. The position, orientation, and driving frequency of the dipole antenna on the photonic band gap crystal surface, have been optimized for antenna performance and directionality. Virtually no radiated power is lost to the photonic crystal resulting in gains and radiation efficiencies larger than antennas on other conventional dielectric substrates. copyright 1995 American Institute of Physics

  5. Layout and cabling considerations for a large communications antenna array

    Science.gov (United States)

    Logan, R. T., Jr.

    1993-01-01

    Layout considerations for a large deep space communications antenna array are discussed. A fractal geometry for the antenna layout is described that provides optimal packing of antenna elements, efficient cable routing, and logical division of the array into identical sub-arrays.

  6. Antenna Gain Impact on UWB Wind Turbine Blade Deflection Sensing

    DEFF Research Database (Denmark)

    Zhang, Shuai; Franek, Ondrej; Byskov, Claus

    2018-01-01

    Antenna gain impact on UWB wind turbine blade deflection sensing is studied in this paper. Simulations are applied with a 4.5-meter blade tip. The antennas with high gain (HG) and low gain (LG) in free space are simulated inside a blade. It is interesting to find that tip antennas with HG and LG...

  7. Reliable Control of Ship-mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2010-01-01

    Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellitewhile the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption in the communi...

  8. Space vehicle electromechanical system and helical antenna winding fixture

    Science.gov (United States)

    Judd, Stephen; Dallmann, Nicholas; Guenther, David; Enemark, Donald; Seitz, Daniel; Martinez, John; Storms, Steven

    2017-12-26

    A space vehicle electromechanical system may employ an architecture that enables convenient and practical testing, reset, and retesting of solar panel and antenna deployment on the ground. A helical antenna winding fixture may facilitate winding and binding of the helical antenna.

  9. Increased operational range for implantable UHF RFID antennas

    NARCIS (Netherlands)

    Dubok, A.; Smolders, A.B.

    2014-01-01

    This paper discusses the main design challenges of implantable UHF RFID antennas in lossy environments. A novel cylindrical implantable antenna concept is presented. The proposed antenna shows good performance inside lossy environments, like a human body. The RFID tag is able to work in a range up

  10. Review of Large Spacecraft Deployable Membrane Antenna Structures

    Science.gov (United States)

    Liu, Zhi-Quan; Qiu, Hui; Li, Xiao; Yang, Shu-Li

    2017-11-01

    The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer (SMP)-inflation, and electrostatic forming. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials (including polyester film and polyimide film) for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different tensioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures, materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.

  11. Global design of an active integrated antenna for millimeter wave

    OpenAIRE

    Marzolf, Eric; Drissi, M’hamed

    2001-01-01

    An active integrated antenna working in the millimeter wave has been realized in a monolithic process. The concept of active integrated antenna is first introduced, then the design of the integrated circuit based on a global approach, following electromagnetic and circuit simulations, is presented. The obtained performances of the active antenna are discussed and compared to a passive one.

  12. Inkjet printed circularly polarized antennas for GPS applications

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2014-01-01

    gain of 0.2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 3.8%. The second antenna design comprises a modified monopole in the form of an inverted L and has been termed as circularly polarized inverted L antenna (CILA). The antenna shows a gain

  13. Rapid Prototyping of Electrically Small Spherical Wire Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2014-01-01

    It is shown how modern rapid prototyping technologies can be applied for quick and inexpensive, but still accurate, fabrication of electrically small wire antennas. A well known folded spherical helix antenna and a novel spherical zigzag antenna have been fabricated and tested, exhibiting...

  14. Design of cost effective antennas for instrumentation radars

    CSIR Research Space (South Africa)

    Botha, L

    2012-09-01

    Full Text Available The cost of antennas for instrumentation radars are determined by the development cost. By re-use of the reflector system cost effective antennas can be designed. The factors governing the design of such antennas are described here....

  15. Detuning effect study of High-Q Mobile Phone Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert F.

    2015-01-01

    Number of frequency bands that have to be covered by smart phones, are ever increasing. This broadband coverage can be obtained either by using a low-Q antenna or a high-Q tunable antenna. This study investigates high-Q antennas performance when placed in proximity of the user. This study...

  16. Wide-scan dielectric dome antenna with reduced profile

    NARCIS (Netherlands)

    Gandini, E.; Silvestri, F.; Benini, A.; Gerini, G.; Martini, E.; Maci, S.; Viganò, M.C.; Toso, G.; Monni, S.

    2017-01-01

    In this contribution, a dielectric dome antenna design in Ka-band is presented. The dome antenna is based on the combination of a phased array and a dielectric lens. The goal of the combination of these structures is to enlarge the field of view of the antenna. In particular, the array is considered

  17. Electrically Small Magnetic Dipole Antennas with Magnetic Core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2010-01-01

    This work extends the theory of a spherical magnetic dipole antenna with magnetic core by numerical results for practical antenna configurations that excite higher-order modes besides the main TE10 spherical mode. The multiarm spherical helix (MSH) and the spherical split ring (SSR) antennas...

  18. Reflection color filters of the three primary colors with wide viewing angles using common-thickness silicon subwavelength gratings.

    Science.gov (United States)

    Kanamori, Yoshiaki; Ozaki, Toshikazu; Hane, Kazuhiro

    2014-10-20

    We fabricated reflection color filters of the three primary colors with wide viewing angles using silicon two-dimensional subwavelength gratings on the same quartz substrate. The grating periods were 400, 340, and 300 nm for red, green, and blue filters, respectively. All of the color filters had the same grating thickness of 100 nm, which enabled simple fabrication of a color filter array. Reflected colors from the red, green, and blue filters under s-polarized white-light irradiation appeared in the respective colors at incident angles from 0 to 50°. By rigorous coupled-wave analysis, the dimensions of each color filter were designed, and the calculated reflectivity was compared with the measured reflectivity.

  19. Surface-plasmon-induced modification on the spontaneous emission spectrum via subwavelength-confined anisotropic Purcell factor.

    Science.gov (United States)

    Gu, Ying; Wang, Luojia; Ren, Pan; Zhang, Junxiang; Zhang, Tiancai; Martin, Olivier J F; Gong, Qihuang

    2012-05-09

    The mechanism of using the anisotropic Purcell factor to control the spontaneous emission linewidths in a four-level atom is theoretically demonstrated; if the polarization angle bisector of the two dipole moments lies along the axis of large/small Purcell factor, destructive/constructive interference narrows/widens the fluorescence center spectral lines. Large anisotropy of the Purcell factor, confined in the subwavelength optical mode volume, leads to rapid spectral line narrowing of atom approaching a metallic nanowire, nanoscale line width pulsing following periodically varying decay rates near a periodic metallic nanostructure, and dramatic modification on the spontaneous emission spectrum near a custom-designed resonant plasmon nanostructure. The combined system opens a good perspective for applications in ultracompact active quantum devices.

  20. TE-polarized design for metallic slit lenses: a way to deep-subwavelength focusing over a broad wavelength range.

    Science.gov (United States)

    Zhu, Yechuan; Yuan, Weizheng; Li, Wenli; Sun, Hao; Qi, Kunlun; Yu, Yiting

    2018-01-15

    Slit arrays based on noble metals have been widely proposed as planar transverse-magnetic (TM)-lenses, illuminated by a linearly polarized light with the polarization perpendicular to slits and implementing the focusing capability beyond the diffraction limit. However, due to intrinsic plasmonic losses, these TM-lenses cannot work efficiently in the ultraviolet wavelengths. In this Letter, taking advantage of the unique transmission through metallic slits not involving plasmonic losses, a metallic slit array with transverse-electric (TE)-polarized design is proposed, showing for the first time, to the best of our knowledge, the realization of sub-diffraction-limit focusing for ultraviolet light. Additionally, in contrast to the situations of TM-lenses, a wider slit leads to a greater phase delay and much larger slits can be arranged to construct the TE-lenses, which is quite beneficial for practical fabrication. Furthermore, deep-subwavelength focusing can be achieved by utilizing the immersing technology.