A Dual-Polarized SIW Lens Antenna Array for Rx-/Tx-Integration at K/Ka-Band

The terminal antenna with dual-circular polarization reported here operates around 20 and 30 GHz, that is, in the down- and uplink frequency bands of current satellite communication systems. The passive array, this work focuses on, integrates the receive and the transmit (Rx/Tx) paths in a single aperture. This approach is shown to be advantageous compared to classical solutions with two separate antennas. The modules, the array consists of, are formed by a stack of eight linear subarrays that themselves are composed of an alternating series of four Tx-only and four combined Rx/Tx endfire antenna elements. The resulting brick architecture provides enough real estate for the future implementation of phased-array electronics. The array is implemented in substrate-integrated waveguide (SIW) technology. For improved matching, it is covered with a periodically shaped dielectric lens. A technique is proposed to mitigate cross-polarization in the pointing direction. A module is realized using standard technologies. The relevant array parameters are measured. The module patterns are synthesized from the individual element responses. They confirm the simulated results and, in particular, a bandwidth of more than 2.5 GHz for both Rx and Tx.