K/Ka Dual-Band Reflectarray Subreflector for Ring-Focus Reflector Antenna

A dual-band ring-focus reflector antenna with a reflectarray subreflector is proposed in this letter. Reflectarray elements present rotationally symmetric structure and a phase range of approximately 360° in the two frequency bands simultaneously. Parabolic reflector is chosen as the main reflector, and a polygonal reflectarray aperture consisting of 137 elements is designed to emulate a metal subreflector. A ring-focus reflector prototype with subreflectarrays was fabricated and measured. The simulated and measured results of the reflector antenna demonstrate a good availability of the design method for utilizing subreflectarrays into the ring-focus reflector antenna, and a good dual-band performance is shown in gain and bandwidths.