Broadband near-field filters for Simultaneous Transmit and Receive in a small two-dimensional array

In order to enable Simultaneous Transmit and Receive (STAR), it is essential to provide high isolation between antenna elements. A novel technique is presented here in which tunable resonators are used in the near-field of an array of antennas to provide transmission zeros in the coupling between antennas. By using two sets of tunable resonators between each set of adjacent antennas, it is possible to significantly increase the bandwidth of the isolation provided relative to previous topologies used to give isolation between planar antennas.