Optimal Design of Self-Shielded Biplanar Coil Assembly With Miniaturized Structure

The multichannel optically pumped magnetometer (OPM) system can experience crosstalk between adjacent sensors owing to the magnetic field generated by the magnetic coil. To mitigate this issue, this study proposes a design for a self-shielded biplanar coil assembly with a miniaturized structure, utilizing the target field method (TFM). Our approach involves setting different interplane spacings between each pair of planar coils to achieve high uniformity in all three axes. To further improve the field homogeneity and self-shielding effect, the particle swarm optimization with linearly decreasing inertia weight (LDW-PSO) is introduced into TFM to design self-shielded coils. This method reduces dependence on the position distribution of target points. Our results indicate that the maximum absolute value of field relative inhomogeneity errors of Bx and Bz are 14.4% and 10.0%, respectively. Furthermore, the maximum absolute value of the external relative field at 16 mm from the center is approximately 1%, meaning that the influence of crosstalk can be ignored.