FOUR BASIC FUNCTIONS AND GENERALIZED ELEMENT FACTORS CONSIDERING SAW VELOCITY DISPERSION EFFECT

摘要

A general approach for the description of thernelectrostatic field in an infinite regular electrode gratingrnis presented. The general approach leads to four basicrnfunctions: a potential-basis, a voltage-basis, a dipolebasisrnand a charge-basis. These four basic functions arernfour degrees of freedom to approximate an electrostaticrnfield for IDT of different structures. On the other hand,rnthe usage of these four basic functions in the synthesisrnproblem leads to four types of the IDT topologyrnimplementation.rnGeneralized frequency element factors are written forrnthe assumption the SAW waves propagate with differentrnwave numbers within an electrode and within an interelectroderngap. This generalization explains the SAWrnspectrum behavior for high harmonics and especially forrnthe SAW devices made up on piezo-film.