GPS RF Front-End Circuit Design

Global Positioning System,called GPS for short,is used to accurately locate the object on the ground or in the air.As the extensive application of this locating technology,it brings huge changes in people's daily life.In the GPS receiver,GPS RF front end circuit is very important.Its performance directly affects on GPS receiver sensitivity and signal processing.So it is valuable to research and design the GPS RF front end circuit.The low-noise amplifier(LNA) and antenna are the critical components in the RF receiver.The duty of antenna is to receive useful signal which is very weak.The LNA's main function is the amplification,mixing and filtering for the weak signal from the RF receiver antenna to get the intermediate frequency signal used in the back-end circuits of RF receiver.Low noise amplifier(LNA) and antenna are key components in the front-end of RF receiver.As the first stage of the system,the gain,noise figure(NF) and linearity directly affect the performance of the whole circuits.The author access to a large number of references as the basis,component of the GPS system,LNA basic design principles and circular polarization microstrip antenna radiation,as well as the realization of the principle methods of research were carried out in-depth.Based on the analysis,the overall architecture of the RF front-end chip was proposed,antenna and LNA at this band are fulfilled.In the design process of Low-noise amplifier,first of all,based on the design methodology of low-noise amplifier,low-noise amplifier was preliminary designed,LNA circuit were simulated using ADS,and the Performances are optimized and tested.At the same time,A new type circularly polarized circle patch for GPS is proposed.With the help of EM simulation software HFSS,the antenna is designed and optimized.Consequently the antenna is fabricated.The simulation and testing results show that it is satisfied with GPS service requirements.