Fan beam formation using spiral array antennas

Two types of spiral array antennas that form circularly polarized fan beams are numerically analyzed. One is composed of two-arm elliptical spiral elements, and the other is composed of single-arm round spiral elements. It is found that the elliptical spiral array antenna can radiate a wider fan beam than a conventional round spiral array antenna. It is also found that the single-arm spiral array antenna can radiate a fan beam off-normal to the antenna plane.