Source: http://ejta.org/en/carstensen1
Timestamp: 2019-04-22 20:14:38+00:00

Document:
A Surface-Acoustic Wave (SAW) device has been modeled employing a second-order Lagrangian finite-element method. The model is able to describe SAW response variations with arbitrary orientation of the unit crystal cell as compared to the macroscopic device geometry and hence allows for fast SAW design optimization. The model is used to determine the resonance frequency of different SAW device structures. The finite-element results are compared with independent analytical results obtained for two configurations of the applied electrode voltages. In order to obtain significant excitation of SAWs, it is preferable to have the electrode fingers oriented along the  crystal axis direction, which is the direction along the x=y line with z constant. Indeed, characteristics of normal displacement amplitudes as a function of rotation angle between the crystal axes and the electrode fingers at a fixed frequency albeit independent of the frequency verify that strong SAW excitations take place for rotation angles near 45 degrees corresponding to the  direction. Computations of various eigenmodes of both Rayleigh and Lamb type are discussed.
Keywords: SAW, piezoelectric, GaAs, zincblende, rotation.
Сitation: D. Bødewadt Carstensen, T. Amby Christensen, Morten Willatzen, P. V. Santos. Modeling of gallium arsenide surface acoustic wave devices. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2007, 19.
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Dennis Bødewadt Carstensen received his M.Sc. degree in Mechatronic Engineering at the University of Southern Denmark in 2006 after finishing his thesis on "Modelling of Piezoelectric Effects in Solid Crystals and Applications to Surface Acoustic Wave Devices". He is currently employed as a Research & Development Engineer at Danfoss A/S in the subdivision Danfoss Electronic Controls & Sensors.
Torben Amby Christensen received his M.Sc. degree in Mechatronic Engineering at the University of Southern Denmark in 2005 after finishing his thesis on "Multiphysics Mathematical Modelling of Piezoelectric Transducers". He is currently pursuing the Ph.D degree in "Advanced Techniques in Electromagnetic Flow-measurement" at the University of Southern Denmark, in collaboration with Siemens Flow Instruments.
Morten Willatzen is a Professor, Ph.D., at the Mads Clausen Institute for Product Innovation, University of Southern Denmark. His research interests are ultrasonics, piezoelectrics, and semiconductor electronic band-structures.
Paulo V. Santos is a Senior Scientist at the Paul Drude Institute for Solid State Electronics in Berlin. He has a Ph.D. degree in Solid State Physics and is an expert in the physics of surface acoustic wave devices.

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