Coupled electromechanical and electromagnetic simulation of radio frequency microelectromechanical-systems (RF-MEMS) based on compact models approach

In this work, a modelling approach of complete RF-MEMS (MicroElectroMechanical-Systems for radio frequency) passives is discussed. The methodology takes into account both the non-linear electromechanical and the RF behaviour, and is suitable for being implemented and automated within a standard circuit simulator. The intrinsic electromechanical core is based on a structural hierarchical model library implemented in the VerilogA programming language, compatible with most commercial EDA (Electronic Design Automation) tools and circuit development environments. A wrapping lumped element network, extracted from S-parameters measured data, accounts for the electromagnetic RF behaviour of the MEMS device. The complete non-linear network can be hierarchically instantiated within a fully functional schematic environment for mixed domain design optimisation. The model is successfully validated against static and dynamic electromechanical and RF on-wafer measurements, using an optical interferometry profilometer. In particular, this paper discusses how the mentioned approach can be extended in order to include the effects due to the presence of a wafer-level package on the RF characteristics.