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 952 for “"antennas"”.
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Microplasma antennas: characterizing capillary plasma discharges as potential monopole antennas
… not been demonstrated before, as most plasma antennas use fluorescent tubes with inner diameters greater than 2 cm and longer than 30 cm. In order to validate that capillary plasma elements function well as the conductive element in antenna structures, spectroscopic electron density …
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Wideband reconfigurable antennas
… communications. Five novel reconfigurable antennas are presented. One is a switchable log periodic patch array and four are Vivaldi antennas with various forms of reconfiguration. The log periodic is reconfigured by placing switches between the patches and the feed line whilst the Vivaldi …
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Conformal microstrip antennas
Microstrip antennas are widely used in several different technological areas including communication and navigation systems, weapons systems, radars, and telemetry and tracking systems. The microstrip antennas' physical features and simplicity of construction make them especially suited for these …
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Self-Optimizing Metamaterial Antennas
The reconfigurable holographic metamaterial antenna is an attractive new technology for satellite communications, particularly in mobile applications. This antenna is thin, light-weight, consumes little power to operate, and is inexpensive to manufacture. Yet, perhaps its most promising attribute …
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Randomly Spaced Smart Antennas
… The advantages and disadvantages of smart antennas based on random array con- figuration are presented and discussed. Several algorithms have been investigated to study the most suitable ones for optimizing the distribution of the excitation coe- cients. The work discussed herein can be …
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Differentially fed active antennas
… of the state-of-the-art in active integrated antennas. Following that, the ground plane influence on antenna radiation pattern was explored and novel techniques to compensate the effects were presented. It was observed that the current flow in a coaxial cable also affects radiation pattern. …
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Synthesis of Aperture Antennas
Made available in DSpace on 2014-12-04T21:02:43Z (GMT). No. of bitstreams: 1 0010495.pdf: 5614468 bytes, checksum: a322fa88aa78fc84a75417f6b17dd25d (MD5) Previous issue date: 1954
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Physical limitations on antennas
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1952.
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Multifilar Hemispherical Helical Antennas
Helices are broadband antennas that provide moderate gain, largely real input impedance and circular polarization when operating in the axial mode regime. A modified form of the helix, the spherical helix, has been shown to yield similar polarization and gain characteristics over a narrow bandwidth …
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Multiple reflector scanning antennas
… issue important for earth observation radiometer antennas is studied, and a new method to evaluate and optimize such temperature resolution is introduced.
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Log-Periodic Loop Antennas
… and unidirectional patterns. Three prototype antennas were constructed and measured in the Virginia Tech Antenna Laboratory. Far-field patterns and input impedance were measured over a wide range of frequencies. The measured results agree well with the calculated results. Because of its wide …
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Multimode and Multiband Microstrip Antennas
… and multiband matching of microstrip patch antennas. Microstrip patch antennas suffer from many constraints on their performance. One major restriction is their narrow impedance bandwidth. An effective method to resolve this is adding more resonators to the antenna structure to achieve …
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Deterministic Design of Metasurface Antennas
L'abstract è presente nell'allegato / the abstract is in the attachment
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Energy storage in reconfigurable antennas
… potential performance advantages, reconfigurable antennas have seen limited use in mobile devices. These complicated antennas can be challenging to design, especially when the structure is electrically small or mid-sized. With small elements, finite groundplanes, and switches or reactive tuning …
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Millimeter-wave integrated horn antennas
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
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Integrated Filter Antennas for Wireless Transceivers
… carried out on the integration of filters and antennas for wireless transceivers. Filters and antennas are parts of wireless transceivers of all wireless communication systems. Filters and antennas, albeit connected, are separate circuits which take up their own individual space in wireless …
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Wearable antennas for new radar applications
A lo largo de esta tesis, se han diseñado antenas para un sistema radar de ayuda invidentes, operativo en la banda de frecuencias milimétricas de uso libre de 24.05-24.25 GHz. Con el fin de determinar el patrón de radiación óptimo para la aplicación, se ha comparado el rendimiento de diversas …
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