A Novel Resonant Ground Structure Based on a Cavity-Backed DGS

In this letter, a new resonant ground structure (RGS) based on a cavity-backed DGS is proposed. The proposed RGS is similar to a DGS and is modeled by a parallel RLC resonance circuit. Since the proposed RGS utilizes a substrate-filled metallic cavity (SFMC) underneath the DGS, it leads to no back-radiation and high quality factor. The frequency responses and structural parameters are analyzed and verified via simulation and measurement. The quality factor of the proposed RGS with a spiral-shaped defect is larger than that of the DGS with the same defect by a factor of 7.4.