This paper investigates the performance of surface acoustic wave (SAW) devices consisting of reactively sputter deposited scandium doped aluminum nitride (ScxAl1-xN) thin films as piezoelectric layers on sapphire substrates for wireless sensor or for RF-MEMS applications. To investigate the influence of piezoelectric film thickness on the device properties, samples with thickness ranging from 500 nm up to 3000 nm are fabricated. S21 measurements and simulations demonstrate that the phase velocity is predominantly influenced by the mass density of the electrode material rather than by the thickness of the piezoelectric film. Additionally, the wave propagation direction is varied by rotating the interdigital transducer structures with respect to the crystal orientation of the substrate. The phase velocity is about 2.5% higher for a-direction compared to m-direction of the sapphire substrate, which is in excellent agreement with the difference in the anisotropic Young's modulus of the substrate corresponding to these directions.

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The panel acoustic contribution analysis is used to determine the contribution of vibrating panels to the noise level inside closed spaces like a car cabin. The use of numerical techniques makes it possible to rate the panels according to their contributions accounting for the interaction between the structural vibrations and the acoustic pressure at a listening point. We consider the application of the finite and boundary element methods and the numerical Green’s function approaches to the problem and discuss the pros and cons regarding their use. The results show that the numerical Green’s function approach coupled to structure can be effectively used for the panel contribution analysis in situations with multiple panels and few listening points.