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A Design Strategy to Improve the Directivity of Wavenumber-Spiral Frequency-Steerable Acoustic Transducers

L. DE MARCHI, N. TESTONI, A. MARZANI

Abstract


Drastic hardware simplification and cost reduction of Guided Wave (GW) based systems can be achieved by using piezoelectric transducers that, shaped according to a frequency based beam steering concept, present inherent directional capabilities exhibiting preferential radiation/sensing directions. In particular, directional GWs generation and sensing can be achieved by patterning the piezoelectric material lay-out and the electrodes. Frequency steerable acoustic transducers (FSATs) peculiar electrodes’ shape produces a spatial filtering effect which is frequency-dependent, so that a direct relationship can be established between the direction of propagation (wavenumber) and the spectral content of the transmitted/received signal. In this paper we present a novel design strategy of FSAT that enables enhanced sensor directivity by using a local variation of the density of the piezoelectric material.

doi: 10.12783/SHM2015/114


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