Non-Linear Electromechanical RF Model of a MEMS Varactor Based on VerilogA and Lumped-Element Parasitic Network

In this paper we discuss an approach for the implementation of non-linear electromechanical and RF models of complete RF-MEMS devices within a standard circuit simulator, such as Cadence Spectre© or Agilent ADS™. The intrinsic electromechanical core is based on a structural hierarchical model library implemented in VerilogA© language. Moreover, a surrounding lumped element network accounting for the electromagnetic RF behaviour of the MEMS device is extracted from S-parameters measured data. The whole nonlinear model network, composed of the intrinsic VerilogA© core plus lumped-element parasitics, can be analysed within a radiofrequency circuit simulator schematic. The model is fully validated against electromechanical and RF static and dynamic measurements, showing good agreement between simulations and experimental results. The presented modeling approach can be the basis for the development of complete RF-MEMS design technology libraries, aiming at optimum hierarchical designs of MEMS-enabled RF circuit blocks.