Miniaturized design and modeling for spiral defected ground structures on double-layered substrates

摘要

A size-reduced spiral DGS on double-layered substrates with supplementary dielectric slabs is proposed. Because the attached additional substrates with a higher dielectric constant can increase effective dielectric constant faced on the DGS pattern in a ground plane, the spiral DGS pattern can be designed with a smaller size. In addition, impedance and linewidth of microstrip line on the proposed structure can maintain the same characteristics thanks to ground isolation. Simple equivalent circuit and its characterization are provided for double-layered spiral DGS designs. The proposed spiral DGS is implemented based on the equivalent circuitmodel, and itsminiaturization of 50% is verified with good agreements.