Influence of coil parameters on Rayleigh waves excited by meander-line coil EMATs

A 3-D model for Rayleigh wave EMATs operating on the Lorentz force mechanism has been established. Rayleigh waves generated by two Lorentz forces are calculated respectively. The ratio of wire width to spacing interval between neighboring wires (RWWSI) is chosen to study the coil parameter influence of Lorentz forces. The vibration amplitude of Rayleigh waves due to the dynamic magnetic field is almost proportional to the reciprocal of the RWWSI, whereas that due to the static magnetic field decreases slowly with the increase of the RWWSI. The divergence angles of Rayleigh waves due to dynamic magnetic field keep invariable when the RWWSI is less than 0.5, and that due to static magnetic field reach the minimum values and have better detectability when the RWWSI is 0.5. The critical excitation current, at which Rayleigh waves due to static and dynamic magnetic fields are equal, changes sharply when the RWWSI differs.