UHF power transmission system for multiple small self-rotating targets and verification with batteryless quadcopter having rotors with embedded rectenna

摘要

A method of wirelessly transmitting power to multiple small moving or rotating devices by means of UHF radio energy has been devised. The transmission frequency was set to 430 MHz to keep the antenna small (relative to an antenna for the SHF region) and to enable the use of inexpensive off-the-shelf rectifiers. The system can supply power to multiple targets within the beam angle of the transmitting antenna. A self-rotating quadcopter rotor unit (rotor, antenna, rectifier, filter, two motors) weighing less than 5.5 g was developed. A patch-array-style beam antenna for power transmission with a sufficient gain and radiating over a large enough area for multiple nearby targets was also designed. A quadcopter with four rotor units was tested: It hovered about 10 cm above the transmitting antenna, which was driven by 30 W of RF power at a frequency of 430 MHz. The four rotor units received a maximum power of 6 W, yielding a transfer efficiency of around 20%.