Tri-Band GPS Antenna

The development of Tri-band GPS antenna for high-performance has become a hot research topic in domestic and foreign experts. This article describes the development of microstrip patch antenna and the GPS antenna, reviews the theory of circularly polarized multi-frequency broadband microstrip antenna. The GPS antenna with cutting fragment, microstrip power divider, quadrature hybrid network and the antenna with low-multipath ground plane is analyzed based on theory.Based on the above, first of all, a single feed circularly polarized antenna is proposed for GPS application. It is composed of four substrates. The bottom layer of the antenna is a single-fed four-port hybrid ring in order to provide signals for circular polarization. The simulated results show that the antenna has good impedance matching characteristics. In addition, the antenna beam width and circular polarization performance meets the requirements.Secondly, the design of the antenna structure simplification and miniaturization is proposed. The three-patch antenna is reduced to two, making the dual-frequency GPS antenna working in tri-band condition. Without affecting the antenna performance, by improving the antenna substrate dielectric constant, the size of antenna has been reduced nearly 50%.A sample of GPS antenna was produced. The measured results verify the correctness of the design.Finally, for the disadvantages of the antenna which radiation pattern in back is too large, we improve the ability of anti-multipath of antenna by the modification of its ground plane. The simulation results show that the ground plane coating absorbing materials; antenna with low-multipath ground plane, respectively have their own advantages and disadvantages.