The electrostatic problem for the SAW interdigital transducers inan external electric field. II. Periodic structures

摘要

For pt.I see ibid., vol.43, no.6, pp.1150-9 (1996). An exactnsolution of the electrostatic problem for calculating the surface chargenand electric field distributions in an arbitrary periodic interdigitalntransducer (IDT) is given using the results of our companion paper. Annarbitrary external electric field may be specified along the electrodenstructure with the unit cell containing one electrode, or severalnelectrodes, of different widths. The potentials of the electrodes thatnmay be specified are also arbitrary. It is shown that in the casenwithout an external field, the solution includes all the known resultsnas special cases. The case of shorted electrodes in the externalnelectric field is investigated in detail. The surface charge andnelectric field distributions are calculated for a spatially harmonicnexternal field with an arbitrary wavenumber. The results of thencalculations are represented graphically for various ratios between thenperiod of the electrode structure and the wavelength of the externalnfield for the case of a unit cell containing one or two electrodes ofndifferent widths