Self-dependent equivalent circuit modeling of electrostatic comb transducers for integrated MEMS

The paper presents a new equivalent circuit model of electrostatic comb transducers for large-scale integration of MEMS into LSI. The model detects the displacement using a dummy spring to express the current induced by the movement, and the model parameters can be derived from only its dimensions not from external parameters (acting force, applied voltage). In addition, the model is composed from basic circuit components. Therefore it is easily utilized in conventional circuit simulation software. In-plane two-degree-of-freedom comb model was applied to basic SOI resonator and the measured and simulated electrical and mechanical properties showed good agreement in each other. A simple oscillating circuit with constant amplitude control has been tested and the transient responses showed good agreement as well.