A simple wideband microstrip bandstop filter for WLAN and WiMAX band rejection purpose

In this paper, a simple hexagonal wideband microstrip bandstop filter with an open-end stepped impedance stub has been proposed for the rejection of WLAN and WiMAX bands. Controlling the dimensions of the shunt open-end stepped impedance stub, the rejection bandwidth and the level of rejection can be controlled. The structure is very simple and is also easy to fabricate. The final filter structure provides a stop band that extends from 3.19 GHz to 5.36 GHz within and more than -20dB rejection and hence it can reject the 3.5 GHz WiMAX bands and 5.2 GHz WLAN frequency bands. The simulated response has been validated after comparing it with the measured data.