The Design and Implementation of Beidou Satellite Navigation System RF Front-End Filter

In the RF(Radio Frequency) front-end of Beidou navigation system, the high precision filter which filtering some noise of receiving signal plays an important role for the whole system. The designed Filter in this paper is based on the theory foundation of parallel coupled microstrip line band-pass filter which combine the designing method of the traditional filter with microwave circuit simulation software ADS2009(Advanced Design System) and HFSS2013(High Frequency Structure Simulator), calculated the design parameters of microstrip line size and completed the simulation of ideal model in ADS, and then set up the 3D model in the HFSS to carry on the simulation which close to the actual production condition. Furthermore, modified and adjusted the design parameters to ensure that the design of radio frequency narrowband parallel coupled microstrip line band-pass filter circuit can conform to the project requirements of the ideal filter. At last analyzed the relevant simulation results and making simple thermal transfer microstrip line circuit board to test effect. From simulation figure it can be seen that this filter has a high precision, simple design, easy to make, small bandwidth and many other advantages, the design and implementation method possess greater project value.