Superstrate loading effects on the circular polarization and crosspolarization characteristics of a rectangular microstrip patch antenna

The authors present the superstrate loading effect on a circularly polarized rectangular microstrip antenna. The design parameters of the superstrate-loading microstrip antenna for achieving circular polarization at the main-beam direction are discussed. The circular polarization property in the entire main-beam region is also analyzed. Next, the crosspolarization characteristics of a rectangular patch antenna due to the superstrate loading are studied. A great dependence of the copolarized and crosspolarized radiations on the superstrate permittivity and thickness is observed. >