Efficient EM-based variability analysis of passive microwave structures through parameterized reduced-order behavioral models

In this contribution we demonstrate how reduced-order behavioral models allow for extremely accurate and computationally efficient electromagnetic-based variability analysis of microwave passive structures. In particular, we report the MonteCarlo analysis of a wideband matching network at Ka-band, designed with a commercial foundry GaN-HEMT process PDK. As sources of variation we considered the thickness of the two dielectric layers available in the PDK to implement MIM capacitors of different order of magnitude, both exploited in the network. Based on a limited set of electromagnetic simulations, a parameterized behavioral model is extracted and then translated into a parameterized circuit equivalent (SPICE netlist) straightforward to be imported into RF CAD tools. The adopted model, implementing a rational approximation of the simulated S-parameters with rational dependence on the two parameters, provides excellent agreement with electromagnetic simulations, robustness against port impedance change and good extrapolation capabilities.