A Tunable Band Stop Filter for Ku Band Communication Systems using DGS and MEMS Switches

This paper presents a tunable bandstop filter based on an interdigital defected ground structure (DGS) and microelectromechanical (MEMS) switches. The switches are positioned over the bends of the DGS. Depending the switch that is actuated, the effective slot length of the DGS varies and hence the resonant frequency. The resonant frequencies can be further varied by varying the individual branch lengths. The proposed design is modified with three additional MEMS switches in each branch to alter its effective length. The design procedure for varying the branch lengths, and mechanical design of the MEMS switches is also presented. The additional switches create a large number of switching states filling the entire Ku-band with closely spaced resonant frequencies.