Continuously tunable band-stop filter based on coplanar waveguide with defected ground structure

Abstract

A tunable band-stop filter based on coplanar waveguide (CPW) with defected ground structure (DGS) is proposed. Filter structure has DGS-units in the ground plates of the simple CPW transmission line. Resonant frequency tuning achieved with a movement of the metal plates, same size as DGS-units, above the substrate of the CPW line. In down position the DGS-slots are covered by metal plates and filter acts like a coplanar line. In the up-position DGS-units effect on the frequency characteristics like there is no moving metal plates at all. Changing distance between metal plates and substrate leads to continuous resonant frequency tuning.