Influence of element parameters on SV-wave EMAT phased arrays directivity

Electromagnetic ultrasonic transducers (EMATs) phased arrays technology is helpful to improve the sensitivity and efficiency of defect detection, and the performance can be evaluated by the directivity of steering beam. The directivity is affected by transducer parameters such as number of elements, element width, and inter-element spacing. Therefore, the effects of element parameters on the directivity characteristics of shear vertical (SV) wave EAMT phased arrays are studied. It is learned that the pressure along the steering direction increases dramatically and the main lobe width gets narrower as the number of elements increases, whereas the more elements would increase the difficult of hardware development. In addition, the relationships between suppression the side lobes and the search to the appropriate inter-element spacing and element width for improving the beam directivity are pointed out. The validity of phased arrays model is verified by experiments and the results are in good agreements with the simulation.