Design and Implementation of a Circularly Polarized Microstrip Patch Antenna for GPS Application with Input VSWR Tuning Capability

In this paper theoretical and experimental investigation of a right hand circularly polarized microstrip rectangular patch antenna have been presented. The antenna has a coaxial feed and designed for operating at L1 frequency (1575 MHz) of global positioning systems (GPS). The antenna have been simulated and optimized using the HP-HFSS software in combination with Empipe3D. The inherently narrow bandwidth of the antenna was increased to 70 MHz using an air layer. A useful practical method was proposed in order to minimizing the input VSWR of the antenna. Theoretical and measured results have been presented and compared.