Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Radiation performance"”.
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A synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas
… parabolic reflector antennas degrade the overall performance of the antenna. They cause amplitude and phase errors in the aperture field which lower the gain, raise the side lobes, and fill in the nulls. These are major problems in large ->space reflector antenna systems. F or example, future …
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Design, Investigation and Implementation of Hetrogenous Antennas for Diverse Wireless Applications. Simulation and Measurement of Heterogeneous Antennas for Outdoor/indoor Applications, including the Design of Dielectric Resonators, Reconfigurable and multiband DR antennas, and Investigation of Antenna Radiation Performance and Design Optimization
… techniques for expanding bandwidth, enhancing performance, and balancing the operation have been examined through comprehensive simulated and physically fabricated models. Thereafter, a compact DRA, for UWB applications is examined. The combined resultant effects of asymmetric positioning of …
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Modelling and design of compact wideband and ultra-wideband antennas for wireless communications. Simulation and measurement of planer inverted F antennas (PIFAs) for contemporary mobile terminal applications, and investigations of frequency range and radiation performance of UWB antennas with design optimisation using parametric studies.
… by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF …
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Model and design of small compact dielectric resonator and printed antennas for wireless communications applications. Model and simulation of dialectric resonator (DR) and printed antennas for wireless applications; investigations of dual band and wideband responses including antenna radiation performance and antenna design optimization using parametric studies
… are typically of small size, with a high radiation efficiency, often above 95%; they deliver wide bandwidths, and possess a high power handling capability. The principal objectives of this thesis are to investigate and design DRA for low profile personal and nomadic communications …
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Investigation, Design and Implementation of MIMO Antennas for Mobile Phones. Simulation and Measurement of MIMO Antennas for Mobile Handsets and Investigations of Channel Capacity of the Radiating Elements Using Spatial and Polarisation Diversity Strategies.
… wireless-communication frequency bands. The radiation performance and channel capacity of these antennas were computed and measured: the results are discussed in the context of the frequency bands of interest. A comprehensive study of MIMO antenna configurations such as 2 × 1, 3 × 1, 2 × 2 …
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Innovative Tiling Methodologies for the Synthesis of Phased Array Antennas for Advanced Radar and Communications Systems
… the maximum aperture coverage and the best radiation performance is proposed to deal with the synthesis of low/medium-size arrays. Based on the same optimal theorems and still exploiting the algorithmic procedures at the basis of the enumerative approach, an innovative schemata-bas ed …
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Directive antenna using metamaterial substrates
… and the other is parallel plate slab farfield radiation. The S-parameters are obtained from the wave-guide simulation and are used to retrieve the effective permittivity and permeability with which we can estimate the farfield radiation using analytic method. Thus, by comparing the farfield …
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Advanced Design Methodologies and Novel Applications of Reflectarray Antennas
… with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • …
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Arrowhead patch slot antenna for 5G applications
… optimized for better input impedance match and radiation performance. Measurements of the fabricated prototype confirmed the targeted operating frequencies. Furthermore, antenna array configurations are designed and optimized for 5G base stations or terminals. The scanning feature of the antenna …
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Unconventional Architectures and Methodologies for Antenna Array Synthesis
… and control the trade-off between achievable radiation performance and the reduction of hardware complexity imposed by practical feeding constraints. On this basis, a set of optimization-driven synthesis methodologies is developed to address the design of unconventional arrays across different …
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Investigation, design and implementation of circular-polarised antennas for satellite mobile handset and wireless communications. Simulation and measurement of microstrip patch and wire antennas for handheld satellite mobile handsets and investigations of polarization polarity, specific absorption rate, and antenna design optimization using genetic algorithms.
… The results in terms of the antenna size and radiation performance are addressed, and compared to measurements and previously published data.
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Investigation, design and implementation of circular-polarised antennas for satellite mobile handset and wireless communications. Simulation and measurement of microstrip patch and wire antennas for handheld satellite mobile handsets and investigations of polarization polarity, specific absorption rate, and antenna design optimization using genetic algorithms.
… The results in terms of the antenna size and radiation performance are addressed, and compared to measurements and previously published data.
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Design of broad-band dual-polarized microstrip patch antennas with high port isolation for millimeter-wave 5G applications
… to the antenna front to back ratio or radiation performance. In addition, a technique to improve the port to port isolation of the antenna by more than 10 dB is proposed. All designs proposed here achieve isolation levels above 30 dB across the band of interest. Two antenna arrays, a …
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Superdirectivity and the Application of Complementary Split Ring Resonators in Directivity Enhancement of Millimeter-Wave Antennas
… losses, millimeter wave antennas suffer from low radiation performance. Motivated by this limitation, this work investigates superdirectivity for millimeter wave antenna designs. Superdirectivity happens when a radiating body exceeds its maximum theoretical directivity limit. Based on a …
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Broadband Approaches And Beam-Scanning Techniques For Reflectarray Antenna
… low-mass, easy-fabrication, and diversified radiation performance. However, it still has some inherent drawbacks, such as limited bandwidth and scanning range, which are targeted in this dissertation. At first, the array theory approach for radiation analysis of reflectarray antennas is …
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High Angular Resolution Beam Steering Terahertz Antenna Arrays for Imaging Applications
… array sizes. In-unit memory additionally enables performance-enhancing algorithms to mitigate beam squint and radiation sidelobes which improve effective resolution of a wideband FMCW radar image and enable radiation performance approaching that of ideal phase shifters. The concepts are …
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OPTIMAL ANTENNA DESIGNS FOR WIRELESS COMMUNICATION APPLICATIONS
… antenna, a planar antenna with ultra-wideband performance, and an E-shaped patch antenna. A novel very compact planar antenna with wideband performance is proposed and investigated. The proposed antenna has a size of only 9.2 mm x 9.8 mm x 1.52 mm. The size miniaturization is achieved by …
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Design and evaluation of distributed spacecraft missions for multi-angular Earth observation
… spacecraft to address this gap. The science performance metric is chosen to be Bidirectional Reflectance-Distribution Function (BRDF), which describes the directional and spectral variation of reflectance of an optically thick surface element at any time instant. Airborne instruments are the …
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