Close-from model of shunt capacitance and inductance of microstrip step discontinuities

Some results for the inductance and capacitance associated with a step discontinuity in a microstrip are available. We present a model on the based on K.C. Gupta proposal for inductance having a maximum deviation 5% and average deviation 3% for ∈r =9.6 and compare the numerical calibration with de-embedding techniques used in the planar electromagnetic (EM) simulation (SONNET) for ∈r = 2.3, 4.0, 15.1, 20.0 & 40.0. These techniques are used to eliminate the port discontinuities brought by the current/voltage exciting source. The closed form model for step shunt capacitance having a maximum deviation 10% and average deviation 4.66% for 2.3 ≤ ∈, ≤ 40.0 against numerical results of the internal equation method. The models have average deviation 0.027 for the Cp and 0.015 for Ls against the results of Sonnet.