I'm trying to get a more intuitive understanding of resonant inductive coupling. It's supposed be a more efficient way to transfer electrical energy wirelessly, because the coils are only coupled by near fields, and don't waste energy as far field radiation. The efficiency is supposed to increase as Q increases (the resistive component decreases).
Ideally, an LC circuit has a Q of ∞. If you charge up the capacitor in an LC circuit, and then leave it floating in space away from anything else, the energy will cycle back and forth between the L and C. The voltage, current, electric field and magnetic field will all cycle sinusoidally (right?) With ideal components, and no resistive component, this will continue cycling back and forth forever.
Real LC circuits have some resistance, which wastes some of the energy as thermal radiation (in a frequency band related only to temperature), and the cycling eventually dies. I think they also have some other non-idealities that allow energy to escape as far-field electromagnetic radiation (at a frequency related to L and C), correct? What are these non-idealities? Are they independent of the resistive component?
If another identical LC circuit is brought near this oscillating circuit, will energy transfer from one circuit to the other due to the changing magnetic fields? Will this happen even with ideal components that don't have far field radiation? Is there no energy transfer if the coils are perpendicular and the axis of one is coplanar with the other, like this?:
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Will the energy distribute itself evenly among the circuits, so they reach an equilibrium where each is circulating half of the original energy? Or will the energy oscillate back and forth between the two circuits, with one alternately being depleted or full?