In this paper, a finite-element model is used to analyze the performance of a thin-film piezoelectric laminate for power generation applications. The focus is on the effects of residual stress, the ratio of PZT to substrate thickness, the substrate material, electrode coverage, boundary conditions, and side length on the electromechanical coupling coefficient. The results show that the residual stress has the most substantial effect on the electromechanical coupling coefficient and should be minimized to increase the electromechanical coupling. Attention to other design parameters can be used to further optimize electromechanical coupling. Electrode coverage should be kept close to 50%. For Si substrates, a Si/PZT ratio of 4 maximizes the electromechanical coupling coefficient. Substrates with higher stiffness lead to superior electromechanical coupling. The results show that design changes, which lead to increased electromechanical coupling, also lead to greater efficiency.
Bibliographical noteFunding Information:
Manuscript received September 20, 2005; revised June 26, 2006. This work was supported by DARPA MTO’s MicroPower Generation Program and the U.S. Army SMDC under Contract DASG60-02-C0001. Subject Editor C. Liu. The authors are with the School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 USA (e-mail: email@example.com). Color versions of Figs. 1, 3, 5, 6, 8–10 available at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JMEMS.2006.883575
- Electromechanical coupling
- MEMS power generation
- Piezoelectric energy conversion