Spatial power combiner using a planar active transmitarray of stacked patches

An X-band spatial power combiner, which uses a planar transmitarray (TXA) of orthogonally polarized stacked microstrip patches integrated with input and output ports of transistor amplifiers is described. In order to obtain an increased operational bandwidth, the unit cell of the combiner with various stacked patch (SP) configurations is investigated. The configuration showing the smallest insertion losses is chosen for developing a TXA. The constructed spatial combiner includes a 4×4 cell TXA placed between two hard horn antennas. Its performance is assessed experimentally in terms of amplification gain and combining efficiency.