A Fully Parameterized Fem Model for Electromagnetic Optimization of an RF Mems Wafer Level Package

In this paper we present our efforts in characterizing and optimizing the influence of a Wafer-Level Packaging (WLP) solution on the electromagnetic behaviour of RF-MEMS devices. To this purpose, a fully parameterized FEM model of a packaged Coplanar Waveguide (CPW) is presented in order to optimize all the technology degrees of freedom (DoF’s) made available by the fabrication process of the capping part. The model is implemented within the Ansoft HFSS electromagnetic simulator, after its validation against experimental data. Moreover, a simulation approach of a capped RF-MEMS varactor is shown. It is implemented in the Spectre simulator within Cadence environment. The MEMS part is treated by means of a compact model library implemented in VerilogA language. A lumped elements network accounting for the parasitics surrounding the intrinsic RF-MEMS varactor is extracted from experimental data. Finally, the S-parameters description of the package, obtained by Ansoft HFSS simulations, is included in the Spectre schematic.