Increase of Characteristic Impedance of Microstrip Line Using a simple Slot in Metallic Ground Plane

In this paper, a novel compact wideband high-rejection LPF using defected ground structure (DGS) is presented. The proposed LPF consists of etched slots in ground metallic plane as defected ground structure (DGS) and of Hi-Lo structure, which corresponding to capacitance and inductance on the top layer. The effect of the DGS slot on the characteristics of the investigated filter is examined. In this work we have proposed a simple method for increasing microstrip line characteristic impedance that is used extensively in microwave filter design. In order to prove the efficiency of the method, a comparison is made between the new DGS LPF and conventional filters, which shows that the proposed filter with simple etched cells is enough to obtain better performance by suppressing ripples and a very large stopband. Measured results are found to be in good agreement with the simulation results.