Design of a switchable microstrip bandstop filter with signal/dual stopbands

A switchable bandstop filter is proposed herein. In order to achieve switchability between a single ultra‐wide stopband and dual wide stopbands, a complex process of coupling synthesis is not necessarily required. By setting two diodes at the input and output port separately, this bandstop filter can be switched between single and dual stopbands. An exemplary bandstop filter with central frequency at 2 GHz is fabricated on Rogers RO4003C, a substrate with a thickness of 0.813 mm and an area occupying 29.3 × 29.7 mm. Agreement between the theoretical and measured results can validate the proposed circuit.