Circuit models for constant impedance micromachined lines on dielectric transitions

Constant impedance microstrip lines printed across nonuniform thickness substrates are studied. Accurate LC models are described to predict the discontinuity effect for dielectric step changes greater than 200 /spl mu/m at the boundary interface. A variety of step or taper transition combinations in the conductor and dielectric are considered. When compared to full-wave simulations, the successfully modeled designs have return and insertion losses within 3 and 0.33 dB, respectively.