Reconfigurable dual-mode ring resonator matched bandstop filter

This paper demonstrates a reconfigurable dual-mode ring resonator matched bandstop filter. The dual-mode ring resonator structure is composed by two degenerate modes or splitting resonant frequencies using a perturbing stub. The reconfigurable dual-mode ring resonator matched bandstop filter is realized by using PIN diodes as switching elements. This reconfigurable filter provides two states of operation; allpass and bandstop response. Frequency of 1 GHz is chosen to demonstrate this operation. The theoretical analysis together with simulation and measurement results are presented in this paper. As a result, this filter can be reconfigured between allpass and bandstop using PIN diodes at 1 GHz.