Analysis and Design of a Uniform Magnetic Field Coil With a Magnetic Shield Based on an Improved Analytical Model

In this article, a uniform magnetic field coil with a magnetic shield is presented and designed to cancel the geomagnetic field and the surrounding magnetic noises. First, an analytical model of the uniform magnetic field coil with the magnetic shield is developed, based on the Biot-Savart law and the traditional images method. Second, in order to improve the model accuracy, the influence of the noninfinite shield thickness on the magnetic field produced by the uniform magnetic coil is considered using the multireflection theory, and an improved analytical model is obtained. The improved analytical model is verified by the three-dimensional finite-element method, and its accuracy is significantly improved compared to the previous analysis model. Then, the characteristic analysis of the uniform magnetic field coil is carried out using the improved analytical model, and design criteria of the uniform magnetic field coils are given to obtain a large uniform field area. Finally, the uniform magnetic field coil with the magnetic shield was constructed and the resulting magnetic field was tested. The test results show that the improved analytical model can accurately predict the performance of such magnetic field coils with magnetic shields, and can be used for its preliminary design.