Optimal Design of Planar Coils With Reverse Current Distribution for Atomic Devices

The uniform magnetic field coil is an essential component for providing a controllable and uniform magnetic field in applications, such as scientific instruments, industrial equipment, and sensors. In recent years, the rapidly developing atomic devices are being miniaturized and have high requirements on the uniformity of the magnetic field. This study proposes an optimal design method for planar uniform magnetic field coils suitable for atomic devices, which can achieve high uniformity in a simple configuration and small volume. The proposed method combines the magnetic field relative errors of the target field points and innovatively introduces the reverse current distribution to compensate for the nonuniform magnetic field. Additionally, the genetic algorithm (GA) was used to calculate the structural parameters and the current direction under optimal uniformity. The simulation and experimental results demonstrated that the maximum magnetic field relative error of the designed planar coils on the two central axes improved by 89.7% and 31.9%, respectively, in contrast to the commonly used Helmholtz coils. Furthermore, the integration of the triaxial magnetic field was realized without increasing the overall volume of the coil. For the triaxial magnetic field coil, the proportion of the uniform magnetic field area of the designed coil can be increased by over $3\times $ compared to the Helmholtz coil, which is conducive to the improvement of the performance of atomic devices.