Influence of coil parameters on transduction performance of unidirectional EMATs for Rayleigh wave

Electromagnetic acoustic transducer (EMAT) for Rayleigh wave has been widely used as a promising tool for flaw detection of metal plates due to its advantages such as high sensitivity to surface defects and low attenuation. Recently, numerous studies have focused on the unidirectional EMAT for Rayleigh wave as it can overcome the disadvantages such as low signal-to-noise ratio and existence of unfavorable received signals of typical EMAT. Since the unidirectional EMAT has been designed based on the principle of wave interference, its performance is sensitive to the parameters of the coil. In order to fully explore the influence of coil dimensions on the transduction performance of a unidirectional EMAT, a 2-D time domain finite model is established based on the Lorentz force mechanism. Using the model, the influence of coils on the transduction performance of a unidirectional EMAT for Rayleigh wave has been discussed. Experiments have been carried out to verify the validity of that model.