Shaped tri-reflector antenna for a beam steering application

A simple synthesis technique for the two subreflectors in a trireflector antenna system is described. In this method, the reflector surfaces are divided into small sections and only a set of sections comprising one main reflector section and two sections of each subreflector is considered at a time. Assuming that the pieces are locally planar, the differential equations are reduced to algebraic equations and closed-form solutions for the reflector surfaces are obtained. To determine the location of each section, a scheme for extrapolating from the known neighboring points is used, in addition to the energy conservation, the equal-path-length law, and Snell´s law. For the geometry considered, a cosine feed type with -11-dB edge illumination and a uniform aperture field distribution are assumed. The shaped first and second reflectors projected onto the x-y plane are shown.<>