This might sound like a stupid question, but I'm kinda interested in a detailed explanation.
So while inductive charging is rather ubiquitous, things like electric toothbrushes and Qi chargers come to mind, as well as to a lesser extent, wireless charging pads for cars, the are all inductive charging systems, basically forming half of a transformer each (the charger is one half, the charged device the other half).
But would it be technically possible to make such a charging setup, using a large capacitor?
I.e. having an AC source connected to a large plate, forming one half of a large capacitor. The charged device would then form the other half of the capacitor.
I understand the distances would have to be rather small, but in cases like Qi chargers, the're right on top of each other anyway. Also, the dielectric properties of the materials between the two conductive plates, would obviously play a role.
But from a purely engineering perspective, why is it a bad idea? One problem I can come up with, is using very high frequencies. The charger side of the capacitor would essentially be an antenna, with the sizes of a smart phone, that would mean frequencies in the 500MHz-3GHz range. I assume it'd be simply too complicated to use a signal generator at these frequencies to send sizeable amounts of power?