Research Of Saw Resonator’s Propagation Characteristics Based On ZnO Single Crystal

Surface acoustic wave devices have many advantages such as smaller volume, lower energy consumption. Compared to the traditional LC filters, SAW devices run more conveniently and simply in signal processing. The commercial application of 4G promotes the approaching communication field into a high frequency, big bandwidth times. Also, the development of the SAW devices shows the same trend into high frequency and big bandwidth. Furthermore, the growing big data accelerates the speed of the development. In order to keep up with the trend, SAW devices need to be improved, including the use of advanced structure and excellent piezoelectric material. A new piezoelectric material ZnO single crystal is being known gradually due to its bigger electromechanical coupling coefficient which has good performance in the fabrication of big bandwidth devices.Firstly, this paper introduces the theory of the interdigital acoustic surface wave, piezoelectric effect principle of the transducers and piezoelectric materials. Secondly, this paper introduces the structure and principle of surface acoustic wave resonator. Based on the finite element analysis of surface wave propagation characteristics in a piezoelectric material, multiphysics field coupling analysis software Comsol Multiphysics is used to simulate the single crystal ZnO-based surface acoustic wave resonators. Symmetric mode and anti-symmetric mode of the ZnO surface acoustic wave are established. The phase velocity and electromechanical coupling coefficient of the ZnO single crystal are calculated by analyzing the resonance frequency. By analyzing the frequency response, the relationship of the resonator’s input admittance, impedance and frequency is obtained. Furthermore, the relationship of the interdigital transducer’s(IDT) structure with resonant frequency and anti-resonant frequency is discussed. The larger the IDT’s input and output interdigital electrode number is, the less the insertion loss and bandwidth is.In the end, two kinds of surface acoustic wave resonator that meet the international standards are designed and one of them can work at high frequency. At the same time, the applications of the surface acoustic wave resonator in sensing pressure are discussed.