The present invention, as typically embodied, implements an energy source, a transmitting antenna, a receiving antenna, a resonant cavity, and an electricity meter (e.g., voltmeter, ammeter, or power meter) to calibrate an electronic device. Firstly, the receiving antenna is calibrated based on measurement of power that has been generated and transmitted in known quantity, propagated through air, and received by the receiving antenna. Secondly, the resonant cavity is connectively situated between the transmitting antenna and the receiving antenna; the resonant cavity is calibrated based on measurement of power that has been generated and transmitted in the same quantity, propagated through the resonant cavity, and received by the receiving antenna. Thirdly, an electronic device is substituted for the receiving antenna; the electronic device is calibrated based on measurement of power that has been generated and transmitted in the same quantity, propagated through the resonant cavity, and received by the electronic device.