High-Directivity Beam-Steerable Lens Antenna for Simultaneous Transmit and Receive

A monostatic, dual circularly-polarized, high-directivity, and beam-steerable simultaneous transmit and receive (STAR) antenna subsystem is presented. The proposed antenna utilizes the balanced circulator beam forming network approach and graded index lens antenna to achieve high Tx/Rx isolation and directivity greater than 24dB in the 5G band centered around 28GHz. The used lens feed is a dual-polarized square horn antenna designed to have high cross-polarized isolation, low reflection coefficient, and stable phase center. The beams are steered by mechanically rotating the proposed compact lens. A maximum scan loss of 4.5dB is seen in an 80° conic field of view while preserving system isolation (> 43dB). A full-wave analysis based on Ansys-HFSS is used to demonstrate the performance of the proposed STAR lens antenna subsystem.