Design of Circular Polarization Square Microstrip Antenna Using Shifted Feed Line Position and Truncated Corner Patch

This paper discussed the design of a simple square microstrip patch that had a circular polarization type. One application that requires a circular polarization type is global positioning system (GPS) with a working frequency of 1575 MHz. The technique used to produce circular polarization is by shifting the feed line position and truncated corner of the patch. The optimal design was obtained by analyzing the changed of feed line position and truncated corner size of the patch. The initial design was performed theoretically, then simulated using the AWR simulator and measured experimentally. Measurement results using a vector network analyzer show that the antenna design achieves the return loss of -26.04 dB and VSWR of 1.1 at frequency of 1575 MHz. The axial ratio below 3 dB was obtained for the range 1540 - 1580 MHz.