Can you power a circuit with electromagnetic waves, as opposed to a physical connection like with a wire?
yes, but it takes huge amounts of power to get any useful results. before WWII, the idea of using a beam of microwaves to transmit power was investigated. to transfer 100 watts of power at a range of 100 meters would require about 5GW (yes, that's Gigawatts). you have to contend with the inverse square law for far-field coupling, and inverse cube law for near-field coupling. far-field refers to distances where the signal is received using an antenna, and there are no direct inductive or capacitive effects involved.... the wave is travelling through space and encounters an antenna. near-field refers to coupling through local capacitive and induction effects in addition to the propagation of the electromagnetic wave. this is how "wireless" phone chargers work, you have a pancake coil on the charger that couples with a coil attached to the phone, and the two coils act as a transformer. since near-field coupling has a cube law characteristic, small increases in distance between primary or secondary result in huge losses. if a charger secondary is receiving 1 watt when it's 1mm from the primary, moving it apart another millimeter will reduce the received power to 1/8 watt.Can you power a circuit with electromagnetic waves, as opposed to a physical connection like with a wire?
Sounds like an assassination device. Too bad you have to open up the person first anyways to install it...and then need to be nearby to use it.In another life, I designed a through-the-skin inductive coupler big enough to power a human artificial heart (~20W). It was not practical because the heat produced by both the transmit and receive coils would have damaged the tissue between the coils...