Highly effective asymmetric reflector antennas of Cassegrain type

Each antenna presents a considerable contribution to the energy balance of a radio link. It performs two tasks: amplification of a received/transmitted signal and practical performance of space selection of radiation direction. Quantitative parameters describing these tasks are energy gain and radiation pattern (mainlobe width and sidelobe level), respectively. Growing demands concerning radioelectronic systems imply more severe requirements for antennas applied there. The search for a new solution in reflecting antenna design is still a problem to be solved. Reflecting antennas are in some cases hardly replaceable in spite of many existing satisfactory multibeam array structures. At present double reflecting antennas are mostly applied because of some advantages over single-reflecting ones. The most important is their possibility of considerably greater directivity value due to greater uniformity of radiated field distribution. We show a comparison between field distribution in apertures of both single and double reflector antennas. In both cases a uniform source radiation pattern is assumed. An additional and essential advantage of a double-reflector antenna is a very convenient location of the radiating source supply feeder, at the rear part of the reflector.