Design of L band cavity filter for GPS receiver

Filters play a critical role in RF and Microwave systems and the type used depends on the application. It is used in the receiver front end to improve selectivity and in transmitter for spurious /harmonic rejection where low insertion loss and narrow bandwidth are the major requirements. This paper, deals with the design of a narrow band cavity filter in L band with centre frequency of 1575.42 MHz. It is planned to use at the front end of a GPS receiver where the system has to withstand the harsh environment of launch vehicle. The cavity filter is designed for the required specification, simulated and optimized using the software Advanced Design System (ADS) and ElectroMagnetic Professional (EMPro).