A dual linear polarization feed antenna system for satellite communications

Abstract

A dual lineal polarization feed antenna system for satellite communication will be described. It consists of a turnstile-based orthomode transducer (OMT) and two identical duplexers formed by a plane T-junction and of two iris filters. This 4-ports subsystem transmits and receives radio frequency signals in double track in which the transmission Tx is made through two ports having as access the standard rectangular waveguide WR229 while the reception Rx is made through two ports having as access the standard rectangular waveguide WR159. The proposed subsystem overcomes the current practical bandwidth limitations by using a very compact octave bandwidth OMT along with two robust duplexers. The subsystem is working in the extended C-band, the 5.8-7.1 GHz range is used for the uplink, whereas the 3.6-4.8 GHz range is set to the downlink. The presented architecture exhibits a return loss better than 20 dB in all ports, an isolation between the different rectangular ports better than 70 dB and a transmission loss less than 0.15 dB in both frequency bands (3.6-4.8 GHz and 5.8-7.1 GHz) which represents state-of-the-art achievement in terms of bandwidth.