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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 231 to 240 of 1968 (0.029 seconds)Spelling suggestions: "subject:"antenna"" "subject:"ntenna""
| 231 |
Some characteristics of tapered helical beam antennasDay, Paul Chester January 1950 (has links)
No description available.
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| 232 |
Electromagnetically Transparent Feed Networks for Antenna ArraysLee, Eugene Y. 11 September 2008 (has links)
No description available.
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| 233 |
Design and Optimization of a Planar Dual ¿¿¿¿¿¿¿¿¿¿¿¿“ Polarized, End ¿¿¿¿¿¿¿¿¿¿¿¿“ Fire UHF Antenna For a Handheld RFID ReaderGrover, Nikhil 22 June 2012 (has links)
No description available.
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| 234 |
The broadband frequency response of periodic surfaces /Larson, Clayton John January 1980 (has links)
No description available.
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| 235 |
Mid-infrared filters using conducting elements /Rhoads, Charles M. January 1983 (has links)
No description available.
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| 236 |
The transfer characteristics of adaptive arrays in communication channels /Sun, Cheng-Bin January 1983 (has links)
No description available.
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| 237 |
Analysis of reflector antennas with array feeds using multi-point GTD and extended aperture integration/Chang, Yueh-Chi January 1984 (has links)
No description available.
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| 238 |
Performance of digital communication systems with adaptive arrays /Ganz, Matthew W. January 1986 (has links)
No description available.
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| 239 |
Adaptive optimization of signal to noise ratio in receiving arrays /Riegler, Robert L. January 1970 (has links)
No description available.
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| 240 |
The Spiro-Helical AntennaGhoreishian, Idine 11 September 1999 (has links)
A novel antenna made of a spiral wire wrapped into a larger helical shape is introduced. The geometry of this antenna, which is a doubly helical structure, is fully described by five independent parameters, including two radial dimensions, two pitch angles, and the number of turns. Radiation properties of this antenna are examined both theoretically and experimentally. The Numerical Electromagnetic Code (NEC-2) is used to obtain simulation results. A large number of cases with different radii, pitch angles, and number of turns are investigated. Results for far-field patterns, gain, axial ratio, and bandwidth are presented. The influence of parameters on radiation properties are examined. Several prototypes of the antenna were constructed and tested using an outdoor antenna range. Measured far-field patterns are presented over a wide range of frequencies. The measured and computed radiation patterns are in good agreement.
The results of this study indicate that the proposed antenna provides circular polarization and high gain over a wide frequency range. For example, when the number of turns is 10, a gain of 11-14 dB, a boresight axial ratio of less than 3 dB, and a half-power beamwidth of about 40 degrees are achieved over a 30% bandwidth. The side-lobe level for most cases examined is better than 10 dB below the main beam. A unique advantage of this antenna is its much smaller size compared with a conventional helical antenna made of straight wire shaped into a helix. Having about the same radiation characteristics, including gain, circular polarization, bandwidth, and side-lobe level, this new antenna occupies a volume more than 2.5 to 3 times smaller than the conventional helix. This reduction in size, which in turn may imply smaller weight and lower packaging and manufacturing costs, makes the proposed antenna very appealing to many communications and aerospace applications. / Master of Science
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