Effects of a Lumped Element on Defected Ground Structures

In this paper, effects of a lumped element on a DGS (Defected Ground Structure), which is etched on the metallic ground plane, were investigated. In order to demonstrate effects of a lumped element, which is placed on DGS section, we proposed a DGS with a dumbbell shape and implemented a parallel resonator with the proposed DGS. Chip type resistor, inductor, and capacitor were chosen as lumped elements for experiments. Experimental results show that the Q-factor and resonant frequency of the proposed DGS section can be controlled directly by using the external lumped element.