Study the effect of adding new components on conventional microstrip LPF design

In this paper, Design of stepped-impedance (SI) microstrip low-pass filters (LPFs) at different cutoff frequencies are presented. A rectangular split ring resonators (SRRs), complementary split ring resonators (CSRRs), and open stubs structures are used in filter design to get better results rather than the conventional design. Low insertion loss (IL), sharp cutoff LPF, high selectivity, and reduction in size have been achieved by adding those new structures. The effect of adding new components to the conventional design have been studied and simulated by using Ansoft HFSS software. Up to 30% reduction in the size of new filters has been achieved by etching square CSRRs in the ground plane of microstrip line. The group delay values are approximately constant in pass-band interval of LPFs. The selectivity and bandwidth of stop-band after low-pass interval are studied in all designs. The filters are often used in RF circuits and microwave systems.