Analysis of efficiency of EMAT surface wave transducer based on bias magnetic field

In order to improve the conversion efficiency of the conventional Electromagnetic Acoustic Transducer (EMAT) surface wave transducer, this paper proposes a new type of biased magnetic field EMAT transducer. A two-dimensional simulation model of EMAT excited surface wave is established using finite element software to compare and analyze the influence of conventional and biased EMAT on the excited surface wave. Finally, an orthogonal experiment is designed to study the influence of magnet height, magnet width, line height, line width, and coil lift on the excited surface wave of the biased EMAT. The accuracy of the orthogonal experiment was verified by experiment. In addition, the influence of biased magnet on the receiving EMAT was also studied. The research results showed that the amplitude of the excited surface wave of the biased EMAT was 51% higher than that of the conventional EMAT, and this method does not cause main frequency bifurcation distortion in the frequency domain information. The amplitude of the receiving signal using the biased EMAT was 38% higher than that of the conventional EMAT, and the biased EMAT can effectively improve the detection sensitivity.