A fast and accurate solution of the one-dimensional charge distribution in a non-periodic structure

Several SPUDT structures proposed in recent years involve transducer electrodes with wide fingers compared to the smallest finger gap. For these structures the charge distribution will deviate significantly from the results of the fast method, especially for finger widths comparable to the wavelength. Within the approximations of the quasistatic charge distribution we will present a one-dimensional solution in a non-periodic structure, which can be found to desired precision. A closed form solution for both the coupling to a SAW and the potential for an arbitrary charge distribution, given by a predescribed function modified by a Taylor series, has been found. By using these closed form solutions, the boundary conditions for excitation or interaction with a SAW in a transducer structure are satisfied by solving a matrix equation