Low profile controllable microstrip band stop filters with sharp frequency response for suppressing GPS band

In this paper compact and small microstrip band-stop filters to remove the GPS band are proposed and studied. Owing to the important role of GPS systems in different applications such as avionics and navigation systems, it is necessary that other transmitting systems applied in avionics and navigation applications, will have very low effect on GPS system operation. One way is the usage of band stop filters in these structures. C-shaped resonators with different size in adjacent of the transmission line are utilized to create band stop properties. The designed filters have good properties such as simple and compact size, flat frequency response with low insertion loss in the pass band, high selectivity and control capability of center frequency and bandwidth of the stop band. The simulated and measured results of the presented filters are shown in the paper.