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 29 for “"radiation efficiency"”.
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Measurement of antenna radiation efficiency using improved Wheeler cap algorithm
Radiation efficiency measurement can inform the wireless design process by determining the total fraction of accepted power radiated by an antenna. The popular Wheeler cap method can be used to quickly and accurately determine the radiation efficiency of small antennas. However, due to cavity …
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Design and measurement of antennas within lossy materials for IoT applications
… This thesis studies methods of enhancing antenna radiation efficiency in such situations along with an improved, low-cost way of measuring radiation efficiency. Multiple modified Wheeler caps are compared to a conventional design to obtain improved accuracy of the calculated radiation efficiency. …
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Analysis and solutions for RFID tag and RFID reader deployment in wireless communications applications. Simulation and measurement of linear and circular polarised RFID tag and reader antennas and analysing the tags radiation efficiency when operated close to the human body.
… Tag for various applications. In particular, the efficiency of the RFID reader antenna and the detection range of the RFID tag antenna, subject to a small and compact antenna¿s design configuration have been studied. The present work has been addressed directly to reduce the cost, size and …
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Human identification through wearable antenna characteristics
… sensitive antenna design with relatively good radiation efficiency to identify the human with a high classification accuracy yet can be used for communication at the same time.<br/><br/>Biometric generation through antenna-body interaction combines a study of human body morphology with physical …
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High-efficiency Waveguide Tunable Leaky-wave Antennas and Phase-shifters
… discuss several ways that one can increase the radiation efficiency of leaky-wave beam-steerable antennas. In this effort, both frequency and fixed frequency scanned leaky-wave antennas are considered. Specifically, we discuss the design and implementation of a slow-wave frequency-scanned …
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Sound radiation from perforated plates
… of representative models to determine the sound radiation from a perforated plate. The aim of this thesis is to develop such a model that can be used to give quantitative guidance corresponding to the design and effectiveness of this noise control measure. Following an assessment of various …
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Wideband Electromagnetic Band Gap (EBG) Structures, Analysis and Applications to Antennas
… loaded with absorbers to eliminate the backward radiation, but in doing so the radiation efficiency of the antenna is decreased. To enhance the radiation efficiency of the antennas EBG structures are used, but they operate over a narrow band. Uniform electromagnetic band gap (EBG) structures are …
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Performance characteristics on patch antenna with sar reduction using artificial magnetic conductor (amc) for wban applications
… size reduction and shape, gain improvement, more efficiency and combination of the requirements for applications which include health monitoring, military and personal navigation entertainment. Several types of antennas have been developed for WBANs and they have achieved narrow bandwidth, …
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Acoustic prediction and noise control of a refrigeration compressor
… the prediction and control of the acoustic radiation from a Bristol H25A refrigeration compressor are investigated. For the acoustic prediction, a modal decomposition approach is used. To this end, a boundary element model of the shell is created, and it is used to compute the modal …
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Balanced antennas for mobile handset applications. Simulation and Measurement of Balanced Antennas for Mobile Handsets, investigating Specific Absorption Rate when operated near the human body, and a Coplanar Waveguide alternative to the Balanced Feed.
… designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of …
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Research and Development of Low-Profile, Small Footprint Antennas for VHF-UHF Range Applications
… between an antenna's physical length and radiation efficiency has also been established. Therefore, a combination of these constraints complicates the design of low-frequency antennas that have small physical size but with enough radiation resistance to be an efficient radiator when …
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Investigation of Low Profile Antenna Designs for Use in Hand-Held Radios
… input reactance, low input resistance, and low radiation efficiency.Further degradation of radiation efficiency occurs in hand-held radios due to size-reduced ground planes, losses within the plastic device casing, and losses due to coupling with the tissue of the user. These factors may also …
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Integration of microwave and millimeter wave bandpass filters with antennas
… for DRA. Design integration with improved radiation efficiency is achieved by replacing the last resonator of the filter with DRA. The synthesis procedure is presented in detail. Equivalent circuit models are developed to facilitate optimizations of the design. In addition, integrated …
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A Compact RF/Photonic Antenna using a Quantum Dot Mode Locked Laser as a Source
… antenna. To realize the microwave signal radiation generated by the QDMLL, several possible MLL-integrated-antennas are proposed. The prototype integrated antenna is fully described, including the design, fabrication, and characterization of the antenna performance. Additionally, this work …
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A characteristic mode perturbation approach for antenna loading design
… to antennas to modify input impedance and radiation pattern properties. However, reactive loading design approaches based on experience, intuition, and modeling are challenged as the demand grows for antennas with increased functionality and performance. New systematic design methods are …
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Analysis of Highly Coupled Wideband Antenna Arrays Using Scattering Parameter Network Models
… change the operating frequency, bandwidth, and radiation pattern from that of the single isolated element. Thus, there are some fundamental questions that remain regarding the effective operation of highly coupled arrays for beam forming, beam scanning, and aperture reconfiguration. Existing …
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The Fundamental Resonant Frequency and Radiation Characteristics of Wide Angle Conical Antennas
… the peak radiated electric field and the radiation efficiency of the conical antenna as a function of half cone angle was also explored.
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Analysis of the Radiation Mechanisms in and Design of Tightly-Coupled Antenna Arrays
… to achieve a maximum bandwidth, but lower radiation or aperture efficiency results. Conformation is shown to be an ineffective method for AGSW control alone. The Wrapped Bowtie design emerges as a novel design offering nearly a 10:1 bandwidth as a finite array over ground. Some bandwidth …
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Design of Miniature Low-Cost Antennas for Compact Low-Data-Rate IoT Terminals
… its miniaturization significantly degrades its radiation efficiency and bandwidth. Since most IoT devices use low microwave frequencies (≤ 3GHz), where link and energy budgets are more favorable, their antennas are often pushed into the electrically small regime, further complicating impedance …
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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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