A Reconfigurable Bandpass Filter With Multi-Band Switching and Band Shiftability

In this brief, a new reconfigurable bandpass filter is proposed. By loading PIN diodes, switching between three states of broadband bandpass filter (BBPF), dual-band broadband bandpass filter (DBBPF) and dual-band narrowband bandpass filter (DNBPF) can be achieved. This topology can realize band shifting in specific frequency bands by loading cross type resonator and parallel stubs. In order to prove the feasibility of this scheme, the proposed reconfigurable filter with a circuit size of
$0.25\,\,\lambda \text{g}\,\,\times 0.31\,\,\lambda \text{g}$
is designed and tested, which has the advantages of band-shiftable, multiple filtering state switching, simple realization, and small size. The measured results are in good agreement with the simulation results.