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Showing 1 to 20 of 22 for “"Frequency Selective Surfaces"”.
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Spectral-domain analysis of finite-frequency selective surfaces
Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:02Z Item is restricted indefinitely.
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Millimeter Wave Radar Object Detection Through Frequency Selective Surfaces
… performance is to enhance object visibility. Frequency selective reflectors can increase object visibility. This work examines the performance of a mmWave 77 GHz radar system developed by Texas Instruments in conjunction with frequency selective surfaces. Two bandpass frequency selective …
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Spectral Signature Modification By Application Of Infrared Frequency-selective Surfaces
… its signature. This technology is known as frequency selective surface (FSS) technology and is established in the millimeter-wave spectral regime, but is a challenging technology to scale for IR application. Incorporation of thin films and FSS antenna elements on a surface permits the …
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Frequency selective surfaces with lumped and time-varying loads, variable surface impedance, and multiple screens
… a limited class of surface geometries. Since the frequency response of a periodic structure is dependent upon the geometry of the surface, a typical approach to changing the response is to modify the geometry. In the past this meant choosing the element shape, such as a square path or cross, and …
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Investigation into the use of active frequency selective surfaces to extend the absorption bandwidth of a conventional Salisbury screen absorber
… inherent trade-off is due to the fundamental frequency limitations imposed by the constitutive parameters of materials and is more detrimental at microwave frequencies.The aim of the research programme described in this thesis was thus to investigate the use of adaptive complex impedance …
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The Application of Advanced Operator Genetic Algorithms to Electromagnetic Optimization Problems
… optimization of E-plane microwave filters and frequency selective surfaces. Domain decomposition, the technique of breaking a given problem into parts and optimizing each part separately, is shown to accelerate both the analysis of the devices and the convergence of the genetic algorithm. To …
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Techniques for analyzing planar, periodic, frequency selective surface systems
… for single-layer, infinite, planar, periodic frequency selective surfaces (FSS) are thoroughly reviewed. Particular emphasis is placed on practical procedures for implementing the analysis for the case of subdomain basis functions. In this presentation, the focus is placed on concepts which …
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Analysis of periodic structures using finite-difference time-domain method
… due to their wide range of applications such as frequency selective surfaces (FSS), electromagnetic band gap, periodic absorbers, metamaterials and many others. The aim of this work is to develop several algorithms to analyze different types of electromagnetic periodic structures using the …
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Frequency selective surface-based sensing: Theory and applications
"Frequency selective surfaces (FSS) are periodic arrays of resonant elements with a specific (resonant) reflection/transmission response when illuminated by electromagnetic energy. FSSs have been utilized for different applications such as spatial filters, reflectors, lenses, radomes, and more …
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Reconfigurable tunable microwave devices using liquid crystal.
… medical devices. The shortage in the available frequency spectrum for radio communications, the demand for portable wireless devices, and the requirement for more functionality in an even smaller volume, requires the development of new concepts in RF technology. One ideal pathway towards …
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Novel Antenna Beamsteering for Wireless Applications
… Metamaterials (MM) and, more specifically, Frequency Selective Surfaces (FSS), are introduced as base materials on novel beamsteering antenna designs.When these are structured as a transmitarray, i.e. a structure positioned in the near-field of a directive radiating element, such …
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Fast Large-Scale Electromagnetic Simulation of Doubly Periodic Structures in Layered Media
… in extreme ultraviolet (EUV) lithography, metasurfaces, and frequency selective surfaces. Such problems can be solved by rigorous numerical methods like finite-difference time-domain (FDTD) method and finite element method (FEM). However, FDTD and FEM are universal methods far from achieving …
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Advances in non-planar electromagnetic prototyping
… microwave and optical frequencies, and radio frequency lenses that attain resolution beyond the diffraction limit. Though primarily used for facsimile display models, additive manufacturing is uniquely capable of addressing the needs of 3D electromagnetic designs which incorporate non-planar …
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Development And Characterization Of Beamforming Antenna Systems
… antenna system consisting of a single source and frequency selective surface (FSS) is proposed (chapter 2) and investigated. Since the FPC antenna system removes complicated feedline mechanism in array antenna system, it gains high interest to provide higher directivity/gain. Different FSS unit …
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Design of Microwave Front-End Narrowband Filter and Limiter Components
… SIW and HMSIW filters have 1.7 GHz center frequency and 0.2 GHz bandwidth. Simulation and measurements of the filters utilizing combline resonators prove the underlying principles.The second proposed device combines a traditional microstrip bent hairpin filter with encapsulated gas plasma …
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Critical Analysis Of Transmitarray Antenna Design
… of transmitarray design using multilayer frequency selective surfaces (m-fss) approach is carefully studied, and the transmission phase limit of m-fss structure is revealed. The maximum transmission phase range is determined based on the number of layers, substrate permittivity, and layer …
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Stealth technologies based on thin microwave FSS absorbers
… problems in order to improve the radio frequency performance of modern wireless systems. This is achieved by engineering low profile stealthy structures based on metal backed resistively loaded Frequency Selective Surfaces (FSS). <br/><br/>The deployment of ultra-thin (≤ λ/17) microwave …
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Investigation of wide bandgap semiconductors for room temperature spintronic, and photovoltaic applications
<p>"Suitability of wide bandgap semiconductors for room temperature (RT) spintronic, and photovoltaic applications is investigated.</p> <p>Spin properties of metal-organic chemical vapor deposition (MOCVD) – grown gadolinium-doped gallium nitride (GaGdN) are studied and underlying mechanism is …
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Design, simulation and manufacturing techniques for fully textile integrated microwave circuits and antennas
… designs differ in terms of the operating frequency, the design of the textile structure or in the level of integration of the transitions for the experimentally validation in the textile. In Chapter 3, two different filters are also proposed, which are based on the cosimulation between two …
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