Equivalent Circuit Model for a Simple Slot-Shaped DGS Microstrip Line

In this letter, an analytic expression is derived for the resonance frequency of a simple slot-shaped DGS. In equivalent circuit modeling, the capacitance and inductance of the resonance circuit are evaluated from the dimensions of the DGS structure. The effects of equivalent circuit elements of a one-turn spiral DGS in the ground plane and their magnetic coupling to the host transmission line are modeled as a simple lumped-element circuit. The resonance frequencies calculated from the proposed method are compared with those obtained by EM simulation.