Research On The Characteristics Of The Micro-transducers Single Piezoelectric Effect At Scale

In this paper we studied the static characteristic of a piezoelectric unimorph cantilever micro transducer driven by a strong applied electric field and the dynamic electromechanical response of the micro transducer by a ultrasonic wave excitation. The piezoelectric unimorph cantilever micro transducer is a multilayer structure in this paper, consist of piezoelectric layer, elastic layer and top or bottom electrode layers. The thickness of the piezoelectric layer is in micron scale.First, when the piezoelectric layer bent in a strong electric applied field excitation, the electrostrictive effect must be considered, which will cause a nonlinear term-the electric field strength squared-appears in piezoelectric equations directly. The nonlinearities of the piezoelectric layer will change along with the electric field increasing. Experiments show that:When feature sizes of structure in the micro scale, the mechanical behavior are significantly different with macroscopic dimensions, and greatly depend on the feature size, this feature is called the scale effect. So in this article will study the static strain transducers under the scale effect will apply couple stress theory. Last, since the cantilever bending transducer work in the general vicinity of the resonance frequency of the bending vibration,and therefore, in order to obtain the best performance of the transducer, which requires to study the dynamic characteristics. This paper use modal analyze to analyze the dynamic electromechanical response of transducer and use MATLAB software to simulate the response.The results showed that:when the thickness of the piezoelectric layer is in micron scale, the layer of the transducer dimensionless stiffness occurred significantly increased, affecting the resonant frequency of the transducer,and causes a corresponding decrease in the charge output at the first order and the output voltage of the transducer.