Multipath mitigation in high precision GPS systems using Artificial Magnetic Conductors

A low profile circularly polarized antenna based on Artificial Magnetic Conductor (AMC) ground plane is presented in this paper. The AMC ground plane is utilized to reduce the effects of multipath by blocking the propagation of surface waves. Hence, the proposed antenna is suitable for high precision GPS systems which require sub centimeter level of precision. Typically, choke ring antennas are used to efficiently reduce the effects of multipath interference. However, they are bulky, heavy and expensive. The antenna presented here consists of a microstrip antenna resonating at the L1 band (1.575 GHz) based on an 8×8 unit cells AMC structure; the result is an antenna showing good multipath rejection and a low axial ratio over a wide angular range. The advantage of the integrated AMC ground plane is the low cost of manufacturing, light weight, and a relatively low profile solution.