Defected ground and patch-loaded planar transmission lines

Two new structures, defected slotline and patch-loaded coplanar waveguide (CPW), are introduced and quasi-static geometrical models for them and for the defected ground structures in microstrip and in CPW configurations are developed, combining those structures with the patch-loaded slotline and the stepped impedance resonators (SIRs) in a microstrip; and thus, a unified approach for the realisation of series and parallel stubs in different planar transmission line configurations is presented. Complementarity between the different structures has been investigated. It has been found that an identical dumbbell-shaped defect and a SIR in a microstrip are complementary to each other. Consequently, a new technique is developed to compensate for the effect of a defect in the ground of a microstrip. All theoretical predictions have been confirmed with both EM simulations and measurements.