Scattering of piezoelectric surface transverse waves from electrodes with arbitrary h/λ

The problem of scattering of surface transverse waves (STWs) from a finite number of massive, elastic fingers with large relative height (thickness) h/λ on piezoelectric substrates is solved by determining the stress and the electric charge densities induced in the finger-substrate interfaces by the impinged waves. Two different mechanisms for the excitation of STW are considered: electrical excitation by a line charge and mechanical excitation by a line force. The resulting responses of the piezoelectric half-space to these elemental excitations lead to a 2×2 dyadic Green´s function G (x,z). It is shown that G(x,z) is capable of describing the mass-loading effect and the natural unidirectionality phenomenon. Based on a reinterpretation of a previous formulation, the complex-valued, frequency-dependent stress distributions on the finger-substrate interfaces induced by the incident STW are calculated exactly. For the calculation of the reexcited acoustic waves, the induced stress is used as the driving term in a first step. The convolution of this equivalent force with the mechanical and the electrical Green´s functions yields the scattered-field patterns