Caustic-fed cylindrical reflector antennas

The present paper gives a simple method for synthesizing a feed system for cylindrical reflector antennas working in UHF and VHF frequency ranges. The antenna radiation characteristics are carefully studied using the method of moments (MoM). The cylindrical reflector is represented by a set of parallel grids. The feeding elements are three half wavelength dipoles located at the caustic of the cylindrical reflector and phased, so that the cylindrical reflector is illuminated in phase. The radiation characteristics, gain and input impedance for different dimensions of the antenna are considered. Also the effects of changing the frequency and feeding elements locations on the antenna performance are studied. The results show that this antenna is very sensitive for both frequency variations and feeding elements phase shifting.