Development and Testing of a MEMS Piezoelectric Energy Harvester

This paper presents a finite element analysis of an interdigitated (d(33)) piezoelectric unimorph cantilever beam for harvesting vibration energy. The key feature that is analyzed is the poling behavior of the piezoelectric material. While simplified models of interdigitated piezoelectric devices assume some uniform and well-defined poling pattern, the finite element modeling shows that not to be the case. In this paper, a "percent poling factor" is developed with which to capture the real losses associated with non-uniform poling. A parametric study is carried out in which electrode patterns, piezoelectric layer dimensions and electrode dimensions are varied to see their effect on this percent poling factor. Optimal parameters are pointed out. Finally, experimental energy harvesting results for a micro-scale interdigitated beam are presented.