The Application Of Microwave Crystal Structure In GPS Antenna

With the application fields of the satellite positioning technology continuously expanding, the diversified Global Positioning System (GPS) receiver terminal styles increase greatly, which makes different demand for GPS antennas. Microstrip GPS antenna is one of the most common antennas. How to improve the performance of the antenna is an issue which is very concerned in the industry area. In recent years, microwave photonic crystal structures with its unique nature have become a new hotspot in science area. This thesis will systematically study the application of the microwave photonic crystal structures in GPS antennas.The domestic and international development of photonic crystal structure is introduced briefly, and the wireless measurement system is also presented in the first part of the thesis. Then the photonic crystal knowledge and theoretical analysis methods are also discussed, especially include Bloch scattering theory and numerical analysis. And the typical applications of the photonic crystal structures are listed. In the following, the microstrip antenna radiation theory and design methods are explored. And a double-stub resistance matching network is designed and manufactured. According to the microstrip antenna theory, a GPS patch antenna which can be used for commercial is designed independently. Finally, varieties of photonic crystal structures which can improve the performance of GPS antenna are seriously investigated, and some useful conclusions are obtained.In the study of microwave crystal structure GPS antennas, a conventional GPS patch antenna is designed and manufactured as a comparable sample using simulation software. Three kinds of PBG structure are studied in this thesis which can be used to improve the GPS antenna performance, i.e. ground defected PBG structure, sub material PBG structure, high impedance surface PBG structure respectively. Six different PBG structures are designed and optimized and respective PBG GPS antennas are obtained. The measurement results show that the gain and axis ratio of the antennas with PBG structures are improved dramatically and the signal-noise ratio of the receiver with PBG GPS antennas are increased remarkably. These provide a sole fundament for the application of PBG structure in GPS antennas.