Design of A Self-Decoupling Pulsed Eddy Current Array Coil Based on Magnetic Field Cancellation

To tackle the issue of surface-related geological information loss caused by aliasing of original and secondary magnetic fields during pulse eddy current detection, this paper examines the effect of the primary magnetic field on the received signal during the shutdown phase of the pulse signal, with a particular emphasis on shallow signal aliasing. The original magnetic field interference greatly diminishes the accuracy of detecting shallow signals. The paper further investigates the decoupling design of existing transmitting and receiving devices and introduces a self-decoupling pulse eddy current array coil design based on the magnetic field reduction principle. This structure decreases the mutual inductance coefficient between the transmitting and receiving coils, effectively reducing the primary magnetic field interference. Through the analysis of the device's magnetic field distribution schematic and grounding detection simulations, the results confirm that this design successfully decouples the main and induced magnetic fields at the receiving coil, thus eliminating the original magnetic field interference and enhancing the accuracy of early signal detection. In comparison to existing designs, this approach offers substantial advantages in reducing primary magnetic field interference and improving shallow signal detection accuracy, providing novel insights and solutions for the optimization and application of pulse eddy current detection technology.