Wireless power transfer using microwaves at 2.45 GHz ISM band

We have demonstrated wireless power transfer by coupling RF power from a microwave oven magnetron RF source using a dipole at optimum position within the cavity. A 40dBm coupled power is transmitted using a monopole corner reflector antenna having gain of 14.97dBi and a half power beam width of 22 °. At the receiving end a patch antenna is placed at variable distances ranging from 0.307 meters (1 foot) to 4 meters (13 feet). The measured power received varies from 25dBm to 3dBm which is in close agreement with the theoretically calculated value using Friis transmission equation. The received RF power is simulated on Multisim with a rectifier circuit and it is shown that an efficiency of 5.5% to 0.2% with respect to the transmitted power can be achieved as the distance is varied from 0.307 meters to 4 meters.