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 18 of 18 for “"wideband antennas"”.
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A Comprehensive Investigation of New Planar Wideband Antennas
Broadband wireless communications require wideband antennas to support large number of users and higher data rates. Desirable features of a wideband antenna are low-profile, dual-polarization and wide bandwidth in a compact size. Many existing wideband antennas are large in size and some have only …
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Design and characterisation of wideband antennas for microwave imaging applications
… of S11 less than -10 dB. Two corrugated u-slot antennas; namely antenna 1 and antenna 2 are placed on a mirror side of skull phantom to examine their ability to detect an object inside the skull. VeroClear-RGD810 skull phantom containing water is used, and the obtained results are verified using …
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SiGe receiver front ends and flip-chip integrated wideband antennas for millimeter-wave passive imaging
SiGe wideband 77-GHz and 94-GHz front end receivers with integrated antennas for passive imaging have been designed and characterized. These front end systems exhibit wideband performance with the highest gain and lowest noise figures reported thus far for silicon-based systems in the 77-GHz and …
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Analysis, design, and fabrication of Archimedean spiral antennas
The uses for wideband antennas include wideband measurement systems, spread spectrum communications systems, feeds for reflectors and elements in wideband arrays. Here, wideband antennas are discussed and Archimedean spiral antennas are found to be appropriate elements for use in a new type of …
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Ultra-wideband antenna design for microwave imaging applications. Design, optimisation and development of ultra-wideband antennas for microwave near-field sensing tools, and study the matching and radiation purity of these antennas within near field environment.
… order to accommodate such a short pulse, a very wideband antenna with a minimal internal reflection is required. Printed monopole and planar metal plate antenna is implemented to achieve the necessary operating wide bandwidth. The development of new compact printed planar metal plate ultra wide …
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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.
… antenna. The primary requirement of UWB antennas is be able to operate over frequencies released 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 …
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Contribución al desarrollo de herramientas CAD para el análisis y diseño de antenas de banda ultra ancha mediante el método de elementos finitos : Contribution to the development of CAD tools for the analysis and design of ultra-wideband antennas by means of the finite element method
… tools for the optimization of Ultra Wide-Band antennas by means of the Finite Element Method (FEM). The objective of this work is to adequate the versatile and accurate but costly in terms of computational resources, the FEM is, for its use together with optimization algorithms and other CAD …
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Characteristic mode theory for closely spaced dipole arrays
… have traditionally relied on arraying relatively wideband antennas. Recently, planar arrays utilizing narrowband elements have been shown to exhibit good wideband behavior when the elements are spaced less than the typical half wavelength spacing used by designers. The reason behind this result is …
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Wideband Compact Antennas for Wireless Communication Applications
… the past few years, new designs of low-profile antennas for handheld wireless devices have been developed. The major drawback of many low-profile antenna designs is their narrow impedance bandwidth. Furthermore, the market trend of personal wireless devices is moving toward a universal system …
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Fundamental Limits on Antenna Size for Frequency and Time Domain Applications
… resonant, frequency-independent, and ultra-wideband antennas. It is shown that the extended model is useful to understand real-world antennas. Observations from antenna radiation physics and transfer function modeling lead to both corrections and extension of the classical fundamental-limit …
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DESIGN AND IMPLEMENTATION OF MICROSTRIP MONOPOLE AND DIELECTRIC RESONATOR ANTENNAS FOR ULTRA WIDEBAND APPLICATIONS
… This increases the demand on designing UWB antennas that meet the requirements of different UWB systems. In this dissertation, different UWB antennas are proposed such as an antenna that covers almost the entire UWB bandwidth, 3.5-11 GHz, as defined by the federal communication commission …
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Electrically-Small Antenna Performance Enhancement for Near-Field Detuning Environments
… low-profile omnidirectional, electrically-small antennas has evolved from the design and construction of AM transmitter towers eighty years ago to current market demand for battery-powered personal communication devices. Electrically-small antenna theory developed with well-known approximations …
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Indoor Geo-location And Tracking Of Mobile Autonomous Robot
… such as low frequency RF signals and ultra-wideband antennas. In this thesis we propose a novel method for achieving geolocation and enable tracking. Geolocation and tracking are achieved by a combination of Gyroscope and encoders together referred to as the Inertial Navigation System (INS). …
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Ultrawideband and Multi-state Reconfigurable Antennas with Sum and Difference Radiation Patterns
… The conventional forms of such pattern diversity antennas are generally working at a single or multiple narrowband frequencies and are designed for specific applications. Hence, generating sum and difference pattern diversity in wide range of frequencies requires the development of new pattern …
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New Designs for Wideband Hemispherical Helical Antennas
… property of spherical and hemispherical helical antennas is that they provide very broad half-power beamwdiths and circular polarization over a narrow bandwidth. In this thesis, new designs for hemispherical helical antennas are introduced that provide significant improvement in bandwidth, while …
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Development and modelling of new wideband microstrip patch antennas with capacitive feed probes
… of a new capacitive feeding mechanism for wideband probe-fed microstrip patch antennas as well as the implementation of a spectral-domain moment-method formulation for the efficient analysis of large, but finite arrays of these elements. Such antenna configurations are very useful in the …
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Reduction Of Mutual Coupling In Antenna Technology Using Elliptically Shaped Metasurfaces
… of mutual coupling between closely spaced antennas and the increase of antenna bandwidth. This is done first using a graphene monolayer as a cloak to decrease mutual coupling and restore radiation patterns for closely spaced antennas at THz frequencies. The introduction of the graphene …
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A Numerical and Experimental Investigation of Planar Inverted-F Antennas for Wireless Applications
… has grown significantly. Devices having internal antennas have appeared to fill this need. Antenna size is a major factor that limits device miniaturization. In the past few years, new designs based on the microstrip antennas (MSA) and planar inverted-F antennas have been used for handheld …