Design & development of co-polarized Ku-band ground terminal system for very small aperture terminal (VSAT) application

Advances in the communication satellite industry have made it possible to utilize smaller antennas in two-way communication networks, commonly known as VSAT (very small aperture terminal) networks. These typically range in aperture size from 60 cm to 4.5 m. It is now possible to build a system with antennas having significantly less gain than the conventional 3.8 m reflector antenna satisfying the 2/spl deg/ satellite spacing. To eliminate the crosstalk, a co-polarized adapter is typically used between the orthomode transducer (OMT) and the corrugated feed horn. In a simpler alternative approach, a single-piece co-polarized diplexer, connected between the feed horn, the high power transmitter, and the receive LNB, is used to frequency select the uplink and the downlink signals. The diplexer is designed to split the two Rx/Tx bands into two separate pens having the same polarization. This paper describes the development of a co-polarized Ku-band Rx/Tx system. Due to stringent electrical requirements, waveguide technology was selected over the microstrip and/or stripline design approaches. The developed system consists of corrugated conical horn, co-polarized waveguide junction with embedded low- and pass-band filters, and a diamond shape reflector.