MEMS节点化建模及其在集成微系统设计中的应用

为实现MEMS产品的快速设计和性能验证,在借鉴其结构化设计思想即节点分析法的基础上,提出了一种与常规信号流类比不同,适于集成微机电系统快速仿真的等效电路建模思路和方法。首先,对系统及MEMS器件进行功能及结构分解;然后,分别对各基本单元进行节点化建模,并在一定的机电类比规则下将其转换为等效电网络(元件);最后,根据节点变量约束关系,将这些等效网络(元件)逐层重构为器件级和系统级等效电路。结合一类典型MEMS集成系统——梳齿式静电反馈微加速度计的分析实例,对上述方法进行了具体介绍和验证。利用OrCAD等电路仿真器分析、测试了所建立的体现多能域耦合关系的微系统数字化分析原型,结果显示,相对于VHDL-AMS描述法,该模型具有单一域内的更加直观的模型形式和快捷的仿真速度,表明本文提出的方法在复杂MEMS集成系统的分析设计中具有一定的应用价值。

MEMS nodal modeling and its application to design of integrated microsystems

In order to achieve a rapid design and verify the performance of MEMS products, a new approach suited to establishing equivalent electrical representations of an integrated MEMS but different from the conventional signal-flow principle is proposed in this paper. Based on the structured design methodology of the MEMS,i.e., nodal analysis method, this approach starts from the functional decomposition of the system and MEMS device. Then, the nodal models of these decomposed elements (emphases laid on those transductional ones) are created and transformed as equivalent networks or components by rule of a certain electrical analogy, F-V analogy. Finally, according to the constraint relations for node variables (General Kirchhoff's law), the equivalent networks (components) are hierarchically reconstructed as device-level models and system-level equivalent circuits. Aiming at the analysis and design of a comb-shaped electrostatic feedback micro-accelerometer, the approach is specifically illustrated and validated. The achieved computational prototype of such a mixed-domain system can be expediently implemented by OrCAD. Moreover, compared with VHDL-AMS models, it provides that proposed model has more explicit physical conception and more less computation time. It indicates that the approach has its application value in analysis and design of complex integrated MEMSs.