Equivalent Circuit Parameters of Surface-Acoustic-Wave Interdigital Transducers for ZnO/Diamond and SiO2/ZnO/Diamond Structures

Equivalent circuit parameters of surface-acoustic-wave transducers are reported for the [interdigital-transducer (IDT)]/ZnO/diamond, ZnO/IDT/diamond, SiO2/IDT/ZnO/diamond and SiO2/ZnO/IDT/diamond structures. The admittance mismatch, normalized susceptance and transformer turns ratio are calculated for each structure by applying the finite-element method (FEM). Their dependences on the thicknesses of the aluminum electrode, ZnO and SiO2 are examined. Experiments are also carried out to evaluate the admittance mismatch, the results of which agree with the calculated data. It is shown that these structures have large values of admittance mismatch compared with those of conventional surface acoustic wave (SAW) materials such as LiTaO3, LiNbO3 and quartz.