Characterization of circularly polarized square cavity backed antennas

The growth of personal wireless communications systems has generated significant interest in the development of small, broad bandwidth and broad radiation pattern antennas for mobile terminal applications. In addition to the desired circuit and radiation properties of the antennas, physically non-obtrusive antennas are required for mobile terminal applications. In this presentation, low profile cavity backed circularly polarized antennas are studied. Results for a small four arm straight wire segment spiral antenna and two different air dielectric patch radiators are compared and contrasted. Emphasis is placed on achieving circularly polarized radiation over broad angular ranges and two frequency bands.