Frequency-dependent inductance and resistance of foil conductor loops

For both economic and technical reasons, flat thin conductors are of increasing interest in coil-winding. A problem is that at relatively low frequencies the current flow may may be nonuniform over the conductor cross-section. Both inductance and resistance of coils become frequency dependent. We have developed a new and general calculation of these effects, using a circuital model, for a single turn of a foil coil. The nonuniform current flow is described. We show that the extra losses due to this increase with the square of frequency, and that there is a small fall of inductance with increasing frequency.