GPS helix antenna design

The Ground positioning through GPS-Global Positioning System has earned extreme significance in the recent years and has various applications. GPS is well-developed system which was initially established for military objectives and later showed itself in civil applications. It consists of three parts as control, space and user. Receiver antennas are one of most important mechanism which is used on the user side. These antennas have specific central frequency with narrow reception bandwidth and a beam width must be capable of receiving signals coming from low horizontal angles and also the structure 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 GPS applications. In the case when the designed antenna did not meet the required criteria, it was observed that the problem arose from impedance mismatching between the antenna and transmission line and a passive impedance matching circuit has been used in order to eliminate this problem.