A composite C/S band feed for TVRO

The authors describe the development of a composite feed for S- & C-band TV reception from satellites. The specific application is significant in the Indian context where INSAT has TV transmission both at S-band and in C-band frequences. The main advantage of the composite feed stems from the fact that it halves the inventory of reflector dishes. For S-band it works in circular polarization having an N-type interface, and for C-band it has flexibility to have any polarization with the help of a dielectric plate polarizer with a waveguide interface. A very compact circular to rectangular transition has been developed for this purpose. The development has also been engineered to have a simple fabrication process. The whole unit has been qualified from both electrical and mechanical specification considerations and has been put into operation.<>