MEMS interdigitated electrode pattern optimization for a unimorph piezoelectric beam

Abstract

This paper presents optimization of interdigitated (d 33 ) piezoelectric MEMS unimorph cantilever beams for harvesting vibration energy or for tuning resonators. The analysis of the poling behavior of the piezoelectric material is the key feature. While it is common that simplified models of interdigitated piezoelectric devices assume some uniform and well-defined poling pattern, the finite element modeling used in this work shows that not to be the case. A percent poling factor is developed to investigate the real losses associated with non-uniform poling. A parametric study in terms of electrode patterns, piezoelectric layer dimensions, and electrode dimensions is carried out to examine their effect on the percent poling factor. Design guidelines are provided to help ensure that such piezoelectric MEMS devices are developed to obtain optimum energy harvesting or tuning performance.