Quasi-electrostatic charge distribution analysis of the planar interdigital transducer

Abstract

This paper presents an analysis of quasi-electrostatic charge density distribution of the surface acoustic wave (SAW) planar interdigital transducer (IDT). Approximation is realized using Chebyshev polynomials and Green's function without transformation in the spatial spectrum domain. The analysis method is suitable for a long IDT's with arbitrary metallization ratios and electrode-polarity sequences. It is assessing the nonuniform charge distribution of electrodes, interaction of local electric field, the end effects. It is easy to calculate the capacity of each electrode. To reduce errors and duration of calculations for a long IDT as far as possible, it is appropriate to refuse from iterative methods and use the analytical expressions of convolutions. The analytic expressions of the convolution the first six terms of the Chebyshev polynomial with the Green's function are obtained. The total error of approximation is found by calculating the difference between the solutions for finite and infinite periodic systems.

http://dx.doi.org/10.5755/j01.u.66.1.266