Parallel-Shaping Technique for a Ring-Focus Reflector Antenna: A multiband Gregorian ring-focus reflector antenna for the Satcom flyaway terminal

The article describes an innovative shaping procedure for the Gregorian ring-focus reflector antenna with two swappable feed units (horn and subreflector) and a common reflector antenna for the flyaway terminal for communication at the C and Ku bands. Over such a multiband, the main challenge is to achieve a compact antenna structure that meets stringent radio-frequency (RF) specifications. The optimization is carried out to achieve enhanced peak gain and reduction of the sidelobe level through rotationally symmetric shaping of the main and subreflectors. Circular symmetric shaping provides ease in manufacturing of the subreflector and identical segments of the main reflector for portability. The measured results of a prototype model of the shaped ringfocus antenna with swappable feed units support the parallelshaping technique.