Circularly Polarized Elliptical Patch Array Antennas for GPS

Abstract

This paper presents the design of circularly polarized microstrip array antennas. The antenna element, which is an elliptical patch fed by a diagonal microstrip line, radiates right handed circularly polarized (RHCP) waves. 2X1, and 2X2 arrays are designed at the centre frequency of 1.57 GHz. The realized gains are 3.7 dB, 5.7dB, and 8.4dB respectively. The Wilkinson power divider is used to feed the array elements. It divides the input power equally between the radiating patches while providing good isolation. Furthermore, it provide a broadband performance covering a wide frequency range. The designed arrays provide a good impedance matching and directional radiation patterns. The axial ratios (AR) are below 3 dB level within the operating bandwidth. Fabrications have been made to validate the simulated results. A good agreement is obtained between the simulated and the measured results. The designed arrays could be of interest for the Global Positioning System (GPS) application.