A filter configuration including a substrate, a primary microstrip line and a first defected ground structure is disclosed. The substrate has a first face and a second face. The second face is a ground face. The primary microstrip line is arranged on the first face and extends in a first direction. The first defected ground structure is arranged on the second face. The first defected ground structure includes a first section, a first circular section, a second section, a second circular section and a third section that are connected to each other in sequence in a second direction perpendicular to the first direction. The second section is covered by the primary microstrip line in a vertical direction perpendicular to the first and second faces. The primary microstrip line has a width equal to a minimum length of the second section. As such, the filtering effect can be improved.