Tunable and reconfigurable SIW filters

The main purpose of this chapter is to introduce the recent advances in frequency-tunable and reconfigurable SIW filter designs based on the use of frequency-tunable SIW resonators. Overall, it covers the design of bandpass, bandstop, and multifunction filters. This chapter first deals with a frequencytunable bandpass filter design. The basic concepts for a conventional frequency-tunable SIW resonator are briefly reviewed, and a SIW resonator structure suited for the design of filters operating at high frequency bands such as K-band is introduced. A K-band frequency-tunable filter design is also included. Section 9.3 then describes bandstop filter designs using the frequency-tunable SIW resonators. Bandstop filter topologies with and without interresonator couplings are discussed. The bandstop filter topologies containing the interresonator couplings are useful for the design of multifunction filter capable of producing both bandstop and bandpass responses. Section 9.4 introduces the concepts and theories for the design of multifunction filters based on using the bandstop filter topologies containing the interresonator couplings.