Patent ID: 8749441

Claim:
A simultaneous transmit and receive (STAR) antenna system, comprising: a ring array of transmit antenna elements equally angularly distributed about a ring axis, each of the transmit antenna elements having a phase relative to the phase of the other transmit antenna elements wherein the phases increase linearly according to an angular position in the ring array and wherein the phases for an opposite pair of transmit antenna elements differ by 180 degrees; a ground plane disposed under the ring array of transmit antenna elements; an electrically-conductive cylinder disposed on the ring axis above the ground plane; a top ground plane disposed at an end of the electrically-conductive cylinder opposite the ground plane; and a receive antenna element disposed on the ring axis above the electrically-conductive cylinder and top ground plane, wherein a path between each transmit antenna element and the receive antenna element is at least partially obscured by at least one of the electrically-conductive cylinder and the top ground plane to thereby increase isolation between the transmit antenna elements and the receive antenna element.