Investigation of element cross talk in arrays, using 1-3 piezocomposite substrates

Arrays can be defined by an electrode pattern on the surface of a 1-3 piezocomposite substrate, but spurious modes arise when the array electrodes are aligned with the rows of pillars. One method that is used to suppress these spurious modes is to pattern array elements at an oblique angle to the rows of pillars In the piezocomposite. In this paper we confirm theoretically that rotating the array Improves performance using the PZFlex finite element analysis package. Compared to the case with aligned electrodes, rotating the array electrodes suppresses spurious modes by disrupting the periodicity of the piezocomposite along the array azimuth and therefore waves that propagate along the array. However, spurious modes can still arise due to the periodicity Imposed on the structure by the pattern of array electrodes. Rotating the electrodes also ensures that all elements In the array have similar performance characteristics.