Applications of free-space microwave power transmission

Some applications and properties of free-space power transmission are examined. Among the properties discussed are: no mass, either in the form of wire conductors or ferrying vehicles, is needed between the source of energy and the point of consumption; energy can be transferred at the velocity of light; no loss of energy in transferring energy throught the vacuum of space; and the energy transfer is insensitive to a difference in the gravitational potential of the transmitter and receiver locations. Applications discussed include the Solar Power Satellite, high altitude platforms for communications and remote sensing. Also discussed are rectennas and retrodirective arrays. Finally, an expression yielding minimum cost is presented.