THE ELECTROSTATIC PROBLEM FOR THE SAW INTERDIGITAL TRANSDUCERS IN AN EXTERNAL ELECTRIC-FIELD .2. PERIODIC STRUCTURES

An exact solution of the electrostatic problem for calculating the sur face charge and electric field distributions in an arbitrary periodic interdigital transducer (IDT) is given using the results of our compan ion paper [1], An arbitrary external electric field may be specified a long the electrode structure with the unit cell containing one electro de, or several electrodes, of different widths, The potentials of the electrodes that may be specified are also arbitrary, It is shown that in the case without an external field, the solution includes all the k nown results as special cases, The case of shorted electrodes in the e xternal electric field is investigated in detail, The surface charge a nd electric field distributions are calculated for a spatially harmoni c external field with an arbitrary wavenumber, The results of the calc ulations are represented graphically for various ratios between the pe riod of the electrode structure and the wavelength of the external fie ld for the case of a unit cell containing one or two electrodes of dif ferent widths.