Symmetrical Designs of High Selectivity Metamaterialized LPFs

This paper introduces several miniaturized symmetrical designs of high selectivity metamaterialized low-pass filters (LPFs) based on a stepped-impedance (SI) 3rd order Type-I Chebyshev LPF prototype. The pass-band interval of the prototype design manifests a nearly constant group delay (GD) ranging between 0.4-0.45 ns with lower level of ripples. It further exhibits voltage standing wave ratios (VSWRs) starting at value 1 and keeping on a reasonable level of impedance matching. To ensure for considerable metamaterialized LPFs designs, the methodology behind this work has resorted to exploit: split ring resonators (SRRs), complementary split ring resonators (CSRRs), besides open stubs (OSs). Qualities such as sharp cutoff, high selectivity, substantial size reduction, and low insertion loss, have all been achieved. The designs were applied on the Roger substrate material (RO3210) with dielectric constant of 10.2, substrate thickness of 1.27 mm, thickness of microstrip conductor of 0.035 mm, then simulated using the package Ansoft High Frequency Structure Simulator (HFSS). The applications field of these filters involves most microwave (MW) communication systems in diverse civil and military horizons.