**Abstract**

This chapter concentrates on the filter structures using Defected Ground Structures (DGS). Initially, this chapter discusses the limitations of Electromagnetic Band Gap (EBG) structures and the development of DGS structure from EBG structure. DGS is an area of increasing interest in EBG technology. Here the well-known dumbbell DGS structures' features and physics are also discussed. New investigations are presented on the choice of geometrical shapes for the DGS structure as an element for the proposed filters. All the proposed DGS structures used to implement different types of filters (lowpass, bandpass, and bandstop) are validated.

**Keywords:** microstrip filter, defected ground Structures, bandstop filter, split ring, resonators
