A simplified method to reduce dimensions of planar passive circuits using defected ground and defected microstrip structures

In this work, a simplified and accurate mathematical method to predict the reduced dimensions of microstrip circuits by using planes with discontinuities such as defected ground structures (DGS) and defected microstrip structures (DMS) is proposed. The method is based on the increment of the slow-wave factor (SWF) for a microstrip with slotted planes. The procedure is successfully applied to reduce the dimensions of a rectangular patch antenna and a matching network implemented with an open-circuited stub.