Title :
Aperture Efficiency Predictions in Symmetrical Paraboloidal Reflector Antennas With Nonplanar Log-Periodic-Type Feeds
Author :
De Villiers, Dirk I L
Author_Institution :
Dept. of Electr. & Electron. Eng., Stellenbosch Univ., Stellenbosch, South Africa
fDate :
7/3/1905 12:00:00 AM
Abstract :
Nonplanar log-periodic-type antennas are attractive as wideband reflector feeds since they can be arranged to provide an axially symmetric radiation pattern that is stable over a wide bandwidth with near constant input impedance. However, these antennas have a frequency-dependent phase center that causes de focusing and degrades reflector antenna performance when used in wideband systems. This letter presents a technique, which includes radiation pattern as well as defocusing effects, to predict an upper bound for reflector system performance when a nonplanar log-periodic feed is used, resulting in useful design guidelines. Predicted results compare favorably with physical optics simulations.
Keywords :
antenna radiation patterns; aperture antennas; reflector antenna feeds; aperture efficiency predictions; axially symmetric radiation pattern; frequency-dependent phase center; nonplanar log-periodic feed; nonplanar log-periodic-type antennas; nonplanar log-periodic-type feeds; physical optics simulations; reflector system performance; symmetrical paraboloidal reflector antennas; wideband reflector; wideband systems; Antenna feeds; Antenna radiation patterns; Approximation methods; Broadband antennas; Log-periodic antennas; radio astronomy; reflector antennas;
Journal_Title :
Antennas and Wireless Propagation Letters, IEEE
DOI :
10.1109/LAWP.2011.2155615