Limitations and Accuracy of CAD Simulators for Discontinuity Models on GaAs Substrates

This paper presents the results of a study to establish the limitations and accuracy of commercially available CAD simulators for microstrip discontinuities, commonly referred to as the corner, step, tee and cross [l]. Measured S-parameters of these discontinuities fabricated on a 100 micron GaAs substrate are compared against results from TOUCHSTONE, SUPER COMPACT, EMsim and SONNET simulators. Results presented indicate that none of the currently available CAD simulators, used in this study, are capable of predicting microstrip discontinuities performance with sufficient accuracy to permit first time design success in MMIC technology.