138 research outputs found

    2009 Index IEEE Antennas and Wireless Propagation Letters Vol. 8

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    This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

    2008 Index IEEE Transactions on Control Systems Technology Vol. 16

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    This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

    Effect of Two Different Superstrate Layers on Bismuth titanate (BiT) array antennas

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    The microwave industry has shown increasing interest in electronic ceramic material (ECM) due to its advantages, such as light weight, low cost, low loss, and high dielectric strength. In this paper, simple antennas covered by superstrate layers for 2.30 GHz to 2.50 GHz are proposed. The antennas are compact and have the capability of producing high performance in terms of gain, directivity, and radiation efficiency. Bismuth titanate with high dielectric constant of 21, was utilized as the ECM, while the superstrate layers chosen included a split ring resonator and dielectric material. The superstrate layers were designed for some improvement in the performance of directivity, gain, and return loss. The proposed antennas were simulated and fabricated. The results obtained were small antennas that possess high gain and high directivity with 3606, omni-directional signal transmission that resonant types of conventional dipole antenna cannot achieve. The gain of the antenna with the superstrate layer was enhanced by about 1 dBi over the antenna without a superstrate layer at 2.40 GHz

    Enhanced and directional single photon emission in hyperbolic metamaterials

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    We propose an approach to enhance and direct the spontaneous emission from isolated emitters embedded inside hyperbolic metamaterials into single photon beams. The approach rests on collective plasmonic Bloch modes of hyperbolic metamaterials which propagate in highly directional beams called quantum resonance cones. We propose a pumping scheme using the transparency window of the hyperbolic metamaterial that occurs near the topological transition. Finally, we address the challenge of outcoupling these broadband resonance cones into vacuum using a dielectric bullseye grating. We give a detailed analysis of quenching and design the metamaterial to have a huge Purcell factor in a broad bandwidth inspite of the losses in the metal. Our work should help motivate experiments in the development of single photon sources for broadband emitters such as nitrogen vacancy centers in diamond.Comment: 29 pages, 9 figure

    A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 2: Metamaterials and Many More

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    This twoā€part article presents a review of different techniques of mutual coupling (MC) reduction. MC reduction is a primary concern while designing a compact multipleā€inputā€multipleā€output (MIMO) antenna where the separation between the antennas is less than Ī»0/2, that is, half of the freeā€space wavelength. The negative permittivity and permeability of artificially created materials/structures (Metamaterials) significantly help reduce MC among narrowā€band compact MIMO antenna design elements. In this part two of the review paper, we will discuss techniques: Metamaterials; Splitā€Ringā€Resonator; Complementaryā€Splitā€Ringā€Resonator; Frequency Selective Surface, Metasurface, Electromagnetic Band Gap structure, Decoupling and Matching network, Neutralization line, Cloaking Structures, Shorting vias and pins and few more

    A broadband resonant cavity antenna using a metamaterial superstrate consisting of two indentical patch arrays

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    This thesis presents the research work on the development of a broadband resonant cavity antenna (RCA) using a two-layer metamaterial based superstrate and a wideband patch antenna as a primary source. It is shown that the resonant effect in a metamaterial consisting of two identical patch arrays can be used to design an RCA device for broadband performance. The large radiation bandwidth of 40āˆ¼47% with 1-dB-ripple flat band response and the maximum gain of āˆ¼13 dBi have been achieved over the frequency band of 8āˆ¼12 GHz. The dimensions of the compact RCA device are 45x45x24 mm3 (or 1.5Ī»x1.5Ī»x0.8Ī» at 10 GHz). The two-layer metamaterial superstrate is based on an assembled structure using the two liquid crystal polymer (LCP) film substrates each with a printed patch array and separated by an air spacer of 4 mm. This air-based superstrate contributes antenna efficiency; it is lighter and requires less dielectric material. For comparison, the two-layer metamaterial superstrate design is implemented using an FR4 board and it has also been demonstrated to provide similar broadband performance in an RCA device. The Fano resonance effect in the two-layer metamaterial design has been studied. It has been discovered that a sharp resonance can be obtained in such metamaterials when a dielectric spacer is very thin (~100 Āµm). Analysis of current and electric field distributions shows that the observed electromagnetically induced transparency (EIT) associated with the enhanced transmission originates from the effect of trapped-mode resonance in the two-layer metamaterials. The experimental work was carried out using both FR4 and LCP based dielectric spacers. It is shown that the LCP based metamaterials can also be used as an effective absorber near a design frequency of 10 GHz. A broadband source antenna is based on an optimised coplanar waveguide (CPW) fed and aperture coupled patch antenna design. By exploiting the coupling effects of a triple resonances associated with the CPW structure, the aperture, and the patch element, the broadband patch antenna was obtained and used successfully in the development of the broadband RCA device. Impedance and radiation bandwidths of the practical device are measured to be as large as 41% and 43%, respectively. The new fabrication and assembly methods based on laser micromachining of the PMMA polymer have been developed for a successful construction of metamaterial structures and antenna devices

    Artificial Magnetic Materials for High Gain Planar Antennas

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    A new method is proposed to enhance the gain and efficiency of planar printed antennas. The proposed method is based on using artificial magnetic materials as a superstrate for planar printed antennas while maintaining the low-profile attractive feature of these antennas. It is found that the antenna's gain increases as the permeability of the superstrate increases. Due to the lack of low-loss natural magnetic materials in the microwave band, designing artificial materials with magnetic properties has become increasingly attractive in recent years. In particular, using magneto-dielectric superstrates reduces the wavelength in the media leading to a miniaturized composite structure (antenna with superstrate). The split ring resonator SRR is used as a unit cell of an artificial magnetic superstrate for a microstrip antenna to enhance the antenna gain and efficiency. Also, in this work, mechanism of operation for artificial magnetic materials is theoretically investigated. Analytical and numerical methods are provided to model the behaviour of these materials. Full-wave analysis of multilayered periodic structures is an expensive computational task which requires considerable computer resources. In this work, a fast analytical solution for the radiation field of a microstrip antenna loaded with a generalized superstrate is proposed. The proposed solution is based on using the cavity model in conjunction with the reciprocity theorem and the transmission line analogy. The proposed analytical formulation reduces the simulation time by two orders of magnitude in comparison with full-wave analysis. The method presented in this work is verified using both numerical and experimental results for the case of a patch antenna covered with an artificial 3D periodic superstrate. Another useful feature of a microstrip antenna covered with superstrate is controlling the direction and beamwidth of the main beam of the antenna. Beam steering has been traditionally implemented in antenna arrays using phase shifters which result in complex and expensive structures and suffer from high loss and mass. This work provides a novel method to steer the main beam of a patch antenna by partially covering it with a high refractive index superstrate. The beam steering of a single patch is possible because of the dual-slot radiation mechanism of the microstrip antenna (according to the cavity model). Full-wave simulations, analytical modeling and experiments are provided to support the proposed technique of beam steering in planar antennas
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