Study on EMAT configuration for generating SH waves

Shear-Horizontal guided wave is ideal for nondestructive testing due to its simple dispersion characteristics. To generate SH waves, Electro-Magnetic Acoustic Transducer (EMAT) is more suitable than traditional piezoelectric transducers. Instead of known EMAT configurations such as PPM (Periodic Permanent Magnet), we propose an another configuration, which arrays several coils whose windings reverse alternately; Four sets of coils are placed next to each other, and two magnets are set to apply a magnetic field. We calculated dispersion curves to know the group velocities and to decide the optimal input frequency. Further, we did experiments to excite the zeroth-order symmetric mode, the lowest mode of SH wave, on an aluminum plate.