Circuit model of multilayer microstrip step discontinuity using single-layer reduction formulation

New closed-form models for the microstrip step discontinuity to compute shunt capacitance (Cp) and series inductance (Ls) is reported for the substrate 2.3 r 40.0 or more. The model is extended to the multilayer (composite and suspended substrate) microstrip step discontinuity. The average deviation for normalized Cp is 5%, and normalized Ls are 2.9 against the results extracted from Sonnet. For the multilayer step discontinuity, the average deviation in the present model for Cp is 5.2%. The method of moment analysis gives an average deviation of 13.53% for Cp and 5.3% for Ls against the results of Sonnet. Comparison with Sonnet indicates that the static model for simple and multilayer case is valid for h/ 0.42.