Frequency-independent antennas and broad-band derivatives thereof
Article Abstract:
Frequency independent antennas describes the class of antennas that are not limited in the spectrum of bandwidth they can accept. However, it is not possible for an antenna to perform constantly across all frequencies. Creating antennas where performance across frequencies is almost constant involves creating antennas that are logarithmically periodic. Log-periodic antennas are analyzed and periodic structure theory applied to the analysis of log-periodic structures. Log-periodic antennas suffer performance problems due to stop regions on the antennas; methods for eliminating these stop regions are presented. Other log-periodic structures discussed include frequency-independent, circularly polarized patterns, and bidirectional, unidirectional, omnidirectional and conical shapes.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1992
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Antennas on complex platforms
Article Abstract:
Engineers involved in designing antennas must consider not only the antennas themselves, but also the platforms on which the antennas will be placed. Examples of platforms that can potentially affect antenna performance are as varied as buildings, airplanes, ships, trucks and space vehicles. Among the problems associated with platform-dependent antenna design are pattern distortion, antenna to antenna spacial coupling and radiation hazard predictions. Computers can prove extremely useful in modelling antenna performance as it relates to specific platforms and surrounding obstacles. High frequency methods that are used to develop computer codes for antenna simulation are discussed.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1992
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Antennas in the geophysical environment - some examples
Article Abstract:
A basic overview of the use and performance of antennas in conjunction with geophysical research is presented. The performance of antennas is greatly, and often unpredictably, affected by the environment around it, whether it be the earth's crust or the ionosphere. A simple model that demonstrates that frequency and distance are a strong function of the ambient medium is presented. A borehole experiment is used to describe the use of antennas as a probe for discovering information about the surrounding environment. The experiment is used to examine the role of telecommunications and remote sensing as they relate to geophysics.
Publication Name: Proceedings of the IEEE
Subject: Electronics
ISSN: 0018-9219
Year: 1992
User Contributions:
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