A source for inducing an electromagnetic magnetic field, comprising: a substrate, a conductive layer coupled to the substrate, and a planar coil coupled to the substrate, wherein the planar coil comprises non-concentric rings, and wherein the non-concentric rings are configured such that a drive current applied across the non-concentric rings provides a magnetic field, and wherein the magnetic field comprises a moment vector that is tilted at an angle from the normal to a plane of the planar coil. Also provided are a method of electromagnetic tracking, a method of manufacture of a planar coil, and an electromagnetic sensor.