PCB Coil Design Producing a Uniform Confined Magnetic Field

We present a magnetic field confining coil with a sub-$10^{-3}$ field uniformity over a large fraction of the coil. The structure is entirely made out of printed circuit boards (PCBs). The PCB design allows to tailor the path of wires to fit the required geometry. We measure the field uniformity with cesium magnetometers in a field range from 1 to 10 $\mu\mathrm{T}$. Our application uses such a coil for an atomic magnetometry-based current controller.