Dual-band offset gimballed reflector antenna

There are two ways to scan a reflector antenna using a gimbal. One is to gimbal the whole antenna assembly, called gimballed antenna assembly. The other is to gimbal the reflector only while the feed and support structure are stationary, called gimballed reflector. The pros and cons for the two approaches are listed. In summary, the gimballed reflector has more advantages than the gimballed antenna assembly such as a simple mechanical structure, light weight, and low manufacturing cost. However, the only disadvantage of the gimballed reflector is the scan loss associated with the feed displacement due to the reflector focal point change. The antenna consists of a front-fed offset gimballed reflector and a circularly polarized dual-frequency band feed. The gimballed reflector allows scanning the beam within any Earth coverage area. The antenna is capable of providing simultaneous EHF reception and SHF transmission for the MILSTAR payload.