Design and synthesis of wide tuning range variable comb drive MEMS capacitors

To present a general synthesis method in the design of variable comb drive MEMS capacitors which can provide specified capacitance versus position profiles while give large tuning range.

By carefully choosing design parameters and constraint conditions, the design process is implemented as the solution of a constraint optimization problem. An electric field analysis software based on the finite element method and an optimization software based on the evolutionary stochastic search are chosen to work together to implement the system.

The results verify that the shape of a variable MEMS capacitor has a great influence on the capacitance versus distance profile and demonstrates that a specific geometry of the MEMS capacitor can be found to match a desired capacitance‐distance profile.

The analytical expression for the capacitance formed between the fixed and the movable fingers is somewhat inaccurate. The results are not compared to measurement because no device has been fabricated.

A very successful numerical simulation example and guidance for MEMS designers to develop MEMS devices with variable electrode shapes.

This paper proposes a systematic way for the design of MEMS tunable capacitors with variable shape. The approach can be used to design MEMS devices with variable electrode shapes to satisfy specific requirements.