In the specific example, the majority of the magnetic flux reaching the power repeater/resonance circuit, and specifically the inductor Lrep, does so via the first surface area 509. This flux may be considered to correspond to a first magnetic signal. Similarly, the majority of the magnetic flux reaching the electromagnetic load 505 from the power repeater/resonance circuit, and specifically from the inductor L, does so via the second surface area 511. This flux may be considered to correspond to a second magnetic signal.

The depth of the intermediate device 501/thermal barrier is typically substantial, and indeed in many embodiments, the distance between the second surface area 511 and the first surface area 509 is at least 1 cm, 2 cm, 3 cm or even 5 cm. Such significant depths may provide a very efficient thermal insulation and protection. Indeed, it may typically allow very hot heating elements to be thermally isolated from thermally sensitive work surfaces. However, an associated disadvantage is that the direct coupling between the power transmitter 201 and the electromagnetic load 505 may be substantially reduced leading to increased power losses etc. In the described approach, these disadvantages are mitigated by the thermal barrier comprising the power repeater 507.