Circularly Polarized Rectangular Patch Antenna with Slot for GPS Applications

In this paper, a circularly polarized rectangular patch antenna with slot is proposed for GPS applications. The geometric structure of the antenna is a rectangular shape with transmission line feed to the rectangular patch. The rectangular patch with slot is designed from an inexpensive FR4 double-sided PCB. The dimensions of rectangular patch with slot for circularly polarized antenna is 60mm, 120mm and 2mm in width (Wg), length (Lg) and height (ha), respectively, to propagate the GPS frequency band of 1.575GHz. On this rectangular patch surface, we have designed a small grooving technique with a width of 2mm and a tilt angle to create a circular polarization. In addition, we also designed this antenna to increase bandwidth by using bandwidth enhancement techniques by grooving the U-slot on the ground plane of the antenna. Based on the results of this antenna simulation, we used to obtain the best proposed antenna parameters and this circular polarization rectangular patch antenna was fabricated and thoroughly tested, respectively. The antenna gain from the simulated results is 3.85dBi and measured at 3.55dBi. The simulated and measured axial ratio (AR) ≤ 3dB cover the operating frequency band (1.563-1.587GHz). And this antenna has the half power beam width (HPBW) in the XZ-plane and the YZ-plane is greater than 65 ° covering the GPS band. In addition, the results of the simulation compared with the measured results show that it is a good agreement for applying this circularly polarized rectangular patch antenna to the GPS applications.