The complex effective surface permittivity of SAW piezoelectric substrates

Abstract
The analysis of the effective surface permittivity which unambiguously characterizes the piezoelectric material features is presented. The use of the effective surface permittivity significantly simplifies the theoretical analysis of the interdigital transducer. It enables the transformation from the complex continuum mechanics problem to the field theory area. The calculations of the complex effective surface permittivity of selected types of dielectric material applied as a basis for the surface acoustic wave devices are presented. The calculations results can be used to estimate the band of the possible bulk waves. Currently it is one of the most crucial problem of the surface acoustic wave devices. The example of the experimental filter with the distorted frequency characteristics described by the imaginary part of the effective surface permittivity is presented.