Exact Analysis of Lamb Waves in Piezoelectric Membranes with Distinct Electrode Arrangements

概要

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Lamb wave devices have been widely used in electro-acoustic and microfluidic devices. In order to improve their performances, the phase velocity dispersion and electromechanical coupling coefficient (ECC) of the Lamb wave should be calculated exactly during designing. Accordingly, this paper aims at analyzing exactly Lamb waves in a single piezoelectric membrane with distinct electrode arrangements. First, the transfer matrix method was employed to calculate the phase velocity dispersion. The ECCs under distinct electrical boundary conditions were calculated by the Green’s function method. Finally, the calculated ECCs were compared with that by using the acoustic velocity difference method. Results show that the differences exist especially in the case of metalized surface, and the coupling coefficients deeply depend on the electrode arrangements. It is concluded that the S0 mode for the metalized surface case is a better choice for a Lamb wave device due to less dispersion, higher velocity, and larger coupling coefficient.
2009-07-25