T/R module design for GEODA antenna

Nowadays, ground stations requirements make it more and more necessary to incorporate conformal antenna structures like dome geometries, as they have many advantages over mechanically controlled reflector antennas. Multi-beam ability and interference rejection are facilitated thanks to the electronic control system of such antennas that improves the ground stations versatility. GEODA is a smart, conformal multi-array antenna system designed for satellite communications. Because of its adaptive beam, it is possible to contact 8 satellites at once, operating at 1.7 GHz. Its complex structure is based on a triangular array configuration, divided into subarrays (cells) of three circular polarised radiant elements. Beam steering control is managed by T/R modules. Until this point in time the reception module of the GEODA has been designed, realised and successfully measured. In this article, the development process to optimise the receive module circuit w.r.t. to size is described, which is at the same time the basic layout used to build an improved transmit unit. This work converts the GEODA project (Rx with single polarization) into the GRUA project (Tx/Rx with double polarization). The combiner circuits and control system that are included in each cell are also described in this paper.