Investigations on RF front end for BeiDou satellite navigation system

A RF front end for the unique BeiDou satellite navigation system of China is designed. It consists of an RF receiver module and an active antenna. The highly integrated RF receiver module is designed based on single conversion scheme, a high performance band-pass IF filter is designed to fulfill the rigorous requirement of the system bandwidth. For the active antenna module, a single-fed circular polarization microstrip patch antenna is designed, and a low noise amplifier is designed to overcome the loss of transmission cable between antenna and RF receiver module. The RF front end for BeiDou system is manufactured and tested. The board size of RF module is 70mm /spl times/ 40mm, and the diameter of active antenna is 65mm. The measurement results agree well with the simulation and satisfy the system requirements.