Multi-Band Reflector Antenna Systems Study.

A study was made to investigate the feasibility of utilizing a single reflector aperture radiating at UHF, L-band, and C-band frequencies. Radiation measurements were performed at UHF (335 MHz) and at L-band (1200 to 1600 MHz). The feasibility of an integrated L-band and C-band feed system was established; however, no measurements were made on the C-band characteristics because it was an optional requirement. Two types of L-band feeds were evaluated: a cavity-backed open-sleeve dipole, and a probe-excited coaxial cavity. The measured VSWR and patterns of these feeds are shown. The cavity-backed dipole feed was incorporated into a 6-ft parabolic reflector to determine the reflector antenna performance at L-band with and without the presence of a UHF dipole mounted at the vertex of the reflector. With the UHF dipole mounted at the vertex of the reflector and as a prime-focus feed, the UHF radiating characteristics were measured. Concepts for integrating a C-band system with the L-band feeds are provided. (Author)