Directivity analysis of meander-line-coil EMATs with a wholly analytical method

Abstract

This paper presents the simulation and experimental study of the radiation pattern of a meander-line-coil EMAT. A wholly analytical method, which involves the coupling of two models: an analytical EM modeland an analytical UT model, has been developed to build EMAT models and analyse the Rayleigh waves’ beam directivity. For a specific sensor configuration, Lorentz forces are calculated using the EM analyticalmethod, which is adapted from the classic Deeds and Dodd solution. The calculated Lorentz force density are imported to an analytical ultrasonic model as driven point sources, which produce the Rayleigh waveswithin a layered medium. The effect of the length of the meander-line-coil on the Rayleigh waves’ beam directivity is analysed quantitatively and verified experimentall