Simultaneous Transmit And Receive with a small planar array

A small three element linear planar array designed to have high isolation between elements for Simultaneous Transmit And Receive (STAR) is demonstrated. This high isolation is achieved through use of tunable resonators that control the near fields of the array without detrimentally affecting the radiated fields. These resonators, which are placed between the patch antenna elements of the array, provide a narrow-band tunable phase shift of the mutual coupling between adjacent elements. By transmitting on the outer two elements and controlling the phase of the coupling from these elements to the middle element, the sum of mutual coupling terms can be reduced by up to 51 dB.