Experiments in the transportation of energy by microwave beam

The recent development of efficient microwave tubes generating hundreds of kilowatts of continuous power at a wavelength of 10 cm has motivated the first initial experiment in utilizing a microwave beam as a means of transporting energy from one point to another. The experiment made use of a CW magnetron operating at 2450 Mc with several hundred watts of power output for the power source, a 9.5 foot diameter ellipsoidal transmitting antenna, a diagonal-horn receiving antenna separated from the transmitting antenna by 25 feet, and a close-spaced thermionic diode rectifier. The overall efficiency as measured from the output of the microwave generator to the input of an electric motor attached to the output of the microwave rectifier at the receiving point was 26%. Although this experiment handled a modest amount of power over a short distance, sufficient "on-the-shelf" technology now exists in each of the component areas to increase the power-handling capability and the distance over which power can be transferred by at least a thousandfold.