Ku-band circular/linear polarized feed system design

During the past several years, satellite communications have used a linear or a circular polarisation in two way communications. As the number of VSAT end users increase, different types of polarized transmission and reception signals are requested. A feed system which combines linear and circular polarisation is the typical new candidate in VSAT antennas. Prodelin Corporation has developed a new Ku-band feed which can operate for both linear and circular polarization at the same time in a reflector antenna. The design requirements are such that the feed can perform simultaneously a circular polarisation, switchable to either RHCP or LHCP, at 11.7-12.2 GHz and a linear polarisation, also switchable to either vertical or horizontal, at 14.0-14.5 GHz. To meet this requirement, Prodelin investigated how the copolarised/crosspolarised feed could be applied to this design with a circular polarizer.