A circularly polarized square-ring patch antenna for GPS application

A novel simplified miniature microstrip-fed square-ring patch antenna with CP radiation has been proposed and tested is presented in this paper. By observing the influence of various parameters on the antenna performance, it can be seen that any design parameter significantly affects the characteristic of CP radiation. The prototype has been designed and fabricated and found to have the bandwidth of 1.1% and 3-dB CP bandwidth of about 0.32% at the center frequency of 1573 MHz. By observing radiation patterns, the 3-dB beam widths of about 100deg indicate the realization of a good circularly polarized characteristic. Measurements and simulations are in good agreement. In addition, the proposed antenna has a small size, effective feeding structure and adequate CP bandwidth, such that it is suitable for use in GPS applications.