Compact lowpass filter design on double-layered DGS transmission lines

A compact double-layered DGS lowpass filter is proposed with miniaturized DGSs. The double-layered structure is composed of a conventional DGS microstrip line attaching a thick dielectric slab of a high dielectric constant, which makes a higher effective dielectric constant on a DGS pattern. The compact DGS lowpass filter is designed with miniaturized DGSs. The equivalent circuit is extracted from single DGSs on double-layered lines. The fifth-state lowpass filter with three DGSs has been implemented and compared with theoretical circuit models and electromagnetic simulated results. From the experimental results, the proposed double-layered DGS lowpass filter has shown good agreements to the design analysis and compared with a conventional DGS filter without an additional lower dielectric substrate to verify miniaturization. © The Korean Institute of Electrical Engineers