In this paper, we proposed new compact DGS low-pass filters with broad stopband and low insertion loss in the pass band. The philosophy of the structure behind this new microstrip low-pass filters is simple as it is composed of a pair of Meander DGS-slots and an open-stub. One Filter will be realized through direct electromagnetic coupling and slow wave effect methods, on the other hand, the remaining filterate will be realized with the DGS and suspended method. With these configurations, the LPF with higher compactness, broad stopband and sharp transition characteristics was realized. The design formulae are derived by using an equivalent-circuit model of a parallel L-C resonator. In order to validate the feasibility of the proposed design method, a low-pass filter with 0.1-dB ripple is designed, fabricated, and measured. The Experimental results agree well with the simulation and analytical results. This article also refers some recent patent on filter designs.
Low-pass filter, microstrip capacitor, meander DGS, compact structure