Wideband simultaneous transmit and receive (STAR) bi-layer circular array

The main challenge with the full-duplex simultaneous transmit and receive (STAR) systems is achieving high isolation over a wide bandwidth while preserving identical (or similar) radiation patterns in both, the transmitting and receiving modes. In this paper, a novel low profile wideband bi-layer STAR circular array configuration is presented. The two layers, one for transmit and the other for receive, are identical and composed of four antenna elements. The proposed approach is based on exciting TX/RX layers with the circular mode 1 phase progression while applying a phase difference between the two layers. Virtually identical radiation patterns and TX/RX isolation >50dB over the wide bandwidth is demonstrated.