Design of Dual Band Circular Polarization Stacked Microstrip Antenna for GPS Applications

Dr Yessar E Mohammed Ali,Ahmed J Abdul Qader

doi:10.33899/rengj.2014.88215

Abstract

In this paper dual-band microstrip antenna for Global Positioning System (GPS) application is designed.This design contents on two circular patch ( upper circular patch, lower circular patch) printed on a two-layer substrate of an FR4 dielectric layer, and cutting a crossed-slot in the upper patch and four I slots in the lower patch. The antenna can work at GPS Ll band (1.575GHz) and L2 band (1.227GHz). The design achieved an approximately impedance bandwidth of 15.8 MHz for L1 for two ports, while L2 band is 11.8 MHz for two ports with maximum gain of 2.54dBi and 1.177dBi in the L1 and L2 band respectively for two ports. The resulting circular polarization (with axial ratio ≤ 3 dB) has been found to meet that required for this application. The VSWR is approximately1.1 (VSWR ≤ 2) for L1 and 1.2 for L2. Results were obtained above using the software CST, which shows that this antenna can meet the demands of the signals of satellite navigation system.The antenna dimensions are (70*70 mm 2 ). The structure is compact and has a good application prospect. The results with low-profile characteristics make the antenna suitable for GPS applications. Keywords: microstrip antenna, GPS antenna, Circular polarization, dual-band antenna, Global Positioning System.

Highlights

Because of their low-profile advantage, circularly polarized (CP) microstrip antennas are very attractive for global positioning system (GPS) applications
Dual-band stacked microstrip antennas, such as antenna structures with an air layer [2] or two different dielectric substrate layers [3], have been reported for GPS. Both the air layer and the two dielectric substrate layers enable the antennas to carry out the dual-band CP operation, thereby achieving good impedance matching at the two CP operating frequencies
The CP antenna can be used to reduce the multipath effect around a GPS receiver [4].The CP antennas are classified as a single feed type or dual feeds type depending on the number of feed point necessary to generate the CP waves

Summary

Introduction

Because of their low-profile advantage, circularly polarized (CP) microstrip antennas are very attractive for global positioning system (GPS) applications. Dual-band stacked microstrip antennas, such as antenna structures with an air layer [2] or two different dielectric substrate layers [3], have been reported for GPS. In this paper a dual band CP stacked microstrip antenna is presented using availably common dielectric laminates, which operates at both L1 and L2 frequency bands for GPS applications.

Results

Conclusion