Distributed-period structures for suppression of spurious modes in 1-3 piezocomposites

Design of periodic 1-3 piezocomposite transducers requires that the period be made small enough to shift the spurious (band-edge) modes to frequencies well above the desired thickness mode. Modelling of one-dimensional composites indicates that band-edge modes can be modified by using multiple-period dicing in the fabrication process. Experimental data confirming this theoretical prediction, and showing that distributed-period dicing is more effective in suppressing spurious modes, are presented for two-dimensionally piezocomposite transducers.