However, wireless power transfer requires several MHz frequencies of operation. At such frequencies, the proximity effect and the skin effect become extremely important. For example, considering Table 1, when there is no spacing between the turns, coil resistance increases approximately 5 times. Fortunately, it could be easily suppressed by increasing spacing between the coils. Also from Table 1, when pole pitch exceeds wire diameters by more than 10 times, the proximity effect is practically negligible.