6DOF Electromagnetic Tracker Electric Field

Magnetic charges do not exist, so the magnetic field exhibits dipole-dipole magnetic (inductive)coupling from transmitter to receiver, so the receiver signal is inversely proportional to the cube of range for ranges short compared to a wavelength (near-field regime).

Electric charges do exist, so the lowest-order electric (capacitive) coupling is monopole-monopole, giving receiver signal inversely proportional to range.

Thus, the angular error due to electric coupling is proportional to the square of range, increasing at larger ranges. The transverse position error in millimeters is thus proportional to the cube of range.