Frequency Selective Surface for Reflector Antenna with Multiple Feeds

A frequency selective surface (FSS) structure of Jerusalem-cross elements aiming for the extension of the number of the feeds of a reflector antenna is presented. The FSS structure comprised two identical back-to-back FSSs separated by a narrow air gap. With the transmission-line circuit representation, the Jerusalem-cross element is described as a microwave stepped-impedance-resonator (SIR). The SIR design aims for the bandwidth improvement, and the passband location of the FSS structure is predominately related to the gap width. A FSS structure that is transparent to Ka-band signal but opaque to Ku-band signal is demonstrated for experimental verification.