Design of a Super High Frequency Tri-Band Antenna Feed for Satellite Communications Terminal

This proposal demonstrates a new and innovative approach to the design and development of a tri-band antenna feed for satellite communications. This novel feed has distinct electrical and mechanical advantages not currently available. The proposed feed is comprised of concentric coaxial waveguide radiators which have a natural geometry for multiple frequency, confocal feeding of a prime focus reflector antenna. The coaxial waveguides maintain a circularly concentric geometry where the annular coaxial regions are employed as radiators in the specified lower frequency bands and the innermost radiator is employed as the highest frequency element. A novel invention of the principal investigators allows polarization diversity to be applied to all frequency bands which is particularly important in satellite communication applications. This invention allows unlimited continuous polarization rotation on all frequency bands, reduced transmission line length improves signal to noise ratios and results in a compact, lightweight antenna feed. In addition to the above features, the proposed feed enables simultaneous transmission/reception on each frequency band without interference to the other channels.