GPS helix antenna design

Abstract

The Ground positioning through GPS-Global Positioning System has earned extreme significance inthe recent years and has various applications. GPS is well-developed system which was initiallyestablished for military objectives and later showed itself in civil applications. It consists of three partsas control, space and user. Receiver antennas are one of most important mechanism which is used onthe user side. These antennas have specific central frequency with narrow reception bandwidth and abeam width must be capable of receiving signals coming from low horizontal angles and also thestructure should be sensitive to right-hand circular polarized waves. In this study, a receiver antenna which is designed in helix form has been implemented for civil GPSapplications. In the case when the designed antenna did not meet the required criteria, it was observedthat the problem arose from impedance mismatching between the antenna and transmission line and apassive impedance matching circuit has been used in order to eliminate this problem.