A Novel Filter Architecture with Five Reconfigurable Filtering Functions

In this paper, a reconfigurable filter architecture that is capable of achieving five reconfigurable filtering functions is presented. The proposed architecture simply consists of a frequency tunable low-pass filter (LPF), a frequency tunable high-pass filter (HPF), a transmission line, and four Pin diodes. By setting different on- and off-states of Pin diodes and manipulating the passband cut-off frequencies of the LPF and HPF, more than five reconfigurable filtering functions including reconfigurable bandpass filter (BPF), bandstop filter (BSF), LPF, HPF, and all-stop filter (ASF) can be obtained. To demonstrate the proposed architecture, a filter prototype using microstrip line technology is designed, fabricated, and measured. The measured results show that the designed multifunctional reconfigurable filter not only successfully achieves various filtering functions, but also demonstrates good reconfigurable performance including fully center frequency (CF) and bandwidth (BW) tunability.