Reconfigurable Bandstop and All-Pass Filter Using Varactor Diode

A reconfigurable bandstop and all-pass filter using varactors is presented. The proposed filter consists of two resonator structures and is excited by a coplanar waveguide feed line. By employing varactors to control the electric field distribution of the filter for achieving the switch between full-pass and band-stop filters. Meanwhile, varying the capacitance value of the varactor diodes enable the bandstop filter to be reconfigured in terms of resonant frequency, bandwidth, and the number of resonant frequencies. The proposed filter offers reconfigurable versatility and can be used for multiple purposes.