Verilog-A Large-Signal RF MEMS Model Library

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Verilog-A RF MEMS Model Library

This SourceForge project hosts an open-source Verilog-A [1,2] library of large-signal RF MEMS capacitor, resonator and switch models [3,4]. The electrostatically-actuated RF MEMS capacitor and switch models are based on a nonlinear damped mass spring system and a nonlinear capacitive transducer, whereas the electrostatically-actuated RF MEMS resonator model is based on a nonlinear damped mass-spring system and two nonlinear capacitive transducers. The reasons for nonlinear behavior are:

The Verilog-A models include electromechanical gas dynamics effects, such as anchor loss, hold-down, hysteresis, self-actuation, squeeze-film damping, spring-hardening, spring-softening, and van der Waals interaction. In addition, noise sources, such as Brownian noise sources and thermal noise sources, are also modeled. Other multiphysics effects, such as acoustoelectric, electrothermal, piezoelectric, pyroelectric and thermomechanical effects, are not included yet.

The Verilog-A models can be used with SPICE solvers for DC, small-signal (AC, noise, S-parameters (SP)) and large-signal (harmonic balance (HB), periodic steady-state (PSS), quasi-periodic steady-state (QPSS), transient) simulation of analog/RF circuits based on RF MEMS components. Some remarks on simulation:

The Verilog-A models allow for specification of beam dimensions and material properties (Poisson ratio, Young's modulus, etc...). Examples of schematics based on gallium nitride (GaN), polysilicon, silicon carbide (SiC) fixed-fixed beam RF MEMS resonators and oscillators, as well as golden capacitive fixed-fixed beam and ohmic cantilever RF MEMS switches, are available upon request. A user guide is being written.

Coming soon

Examples

Examples of schematics based on the OHMIC_CANTILEVER_RF_MEMS_SWITCH and the RF_MEMS_CAPACITOR Verilog-A models can be downloaded.

Requirements

A SPICE solver supporting Verilog-A/Verilog-AMS, such as Agilent ADS, Cadence SpectreRF, or Synopsys HSPICE, is required. Some remarks on installing the Verilog-A models:

Links

[1] Verilog-AMS Language Reference Manual, Version 2.3.1, June 1, 2009, Accellera Organization, Inc.

[2] Hidden State in SpectreRF, Version 1c, May 27, 2003, Ken Kundert, Designer's Guide Consulting, Inc.

[3] Modeling RF MEMS Devices, Koen Van Caekenberghe, IEEE Microwave Magazine, Volume 13, Issue 1, January - February 2012 Page(s): 83 - 110.

[4] Mixed-Domain Fast Simulation of RF and Microwave MEMS-based Complex Networks within Standard IC Development Frameworks, Jacopo Iannacci, Fondazione Bruno Kessler - FBK, MemSRaD Research Unit, Italy

[5] Using Verilog-A in Advanced Design System

[6] Cadence Mixed-Signal Tutorial