Bidirectional circularly polarized microstrip antenna for GPS applications

A bidirectional circularly polarised (CP) antenna for 1.575 GHz GPS L1 band is presented. The antenna consists of two back-to-back coupled patches and is fed directly by 50Ω Coplanar Waveguide (CPW). It is compact and relatively easy to manufacture compared to other antennas with similar properties. The bidirectional CP pattern is achieved by proper adjustment of patch dimensions as well as feed parameters. A study of the key parameter is provided.