A COMPLEX IMPEDANCE THEORY FOR SURFACE ACOUSTIC WAVE INTERELECTRODE MULTIREFLECTION EFFECTS

Starting with the postulation of impedance discontinuity, a complex impedance theory for the interelectrode multireflection effects of surface acoustic wave is presented. In this theory an electrode under the multireflection may be equivalent to a transmission line with a complex wave impedance and a complex propagation phase constant. As a result, the interelectrode multireflection effects could be expressed by simple formula. Thus, not only the frequency response of the equidistance transducers and the reflection coefficients of uniform gratings, but also the reflection coefficients of withdrawed gratings and the frequency responses of the dispersive transducers can be described by these analytical expressions inplace of the commonly used numerical computation of matrix series multiplication which can not tell the relations between the results and the parameters, and is time-consuming in computation.