An improved algorithm for the creation of homogeneous magnetic field distributions

In inductive magnetic coupling, a set of two coils is used to transfer energy and/or information over a wireless, short-range link. In most cases, the generated magnetic field is not homogeneous, even though a homogeneous distribution would be advantageous for certain applications. Recently, an algorithm was proposed to calculate the distribution of the current traces of a planar coil to generate a homogeneous magnetic field. The algorithm gives excellent results, but is limited to about ten current traces because of instabilities of the algorithm. In this paper, we propose an improvement to the algorithm by using the generalized minimal residual method. Our improved numerical procedure eliminates the restriction on the number of traces and leads to a more accurate description of the desired current distribution in order to obtain a homogeneous vertical magnetic field.