Abstract:To address the challenges of low transduction efficiency, poor signal-to-noise ratio, and the influence of internal ultrasonic waves within magnets on signal detection in electromagnetic acoustic transducers (EMAT), conventional methods have employed copper foil backings or magnetic flux concentrators. However, while copper foil backings alleviate magnet resonance, they also reduce signal amplitude. On the other hand, existing flux concentrators suffer from complex structures, manufacturing difficulties, and high costs. This paper presents a novel EMAT design that incorporates a trapezoidal silicon steel concentrator positioned between the permanent magnet and the coil. The trapezoidal concentrator, with its simple structure fabricated using adhesive bonding techniques, effectively eliminates ultrasonic waves within the magnet by increasing the distance between the magnet and the coil. Moreover, its unique trapezoidal shape concentrates the magnetic flux lines into the coil’s active region, thereby enhancing the amplitude of the echo signal. The optimal dimensions of the trapezoidal silicon steel concentrator, which significantly impact the echo signal’ s amplitude, were determined through orthogonal experimental design on the COMSOL simulation platform. The simulation and experimental results demonstrate that the signal amplitude of the EMAT with the optimized trapezoidal concentrator is approximately 60% higher compared to the EMAT without a backplate. Furthermore, the signal amplitude of the EMAT with the optimized trapezoidal concentrator is approximately six times greater than that of the EMAT with a 0. 1 mm copper foil backplate.