A confocal reflector system

The confocal paraboloidal reflector system which changes the input and output beam diameters is often considered as a phased array magnifier. However, the test results show that the antenna performance is less desirable. Recently, due to the realization of the implementation of active phased array in space, for example, S-band phased array of Global Star satellites, has revived interest in a confocal system. The confocal system is particularly attractive to low frequency systems such as S-band systems, where the radiating aperture may become quite large. With the use of the confocal system, one can use a smaller stationary active phased array feed instead of a large deployed full size active phased array. This paper describes an improved confocal system.