A Practical Calibration System for Active Arrayed Wireless Power Transmitter

A system for automatically calibrating an arrayed Microwave Power Transmitter (MPT) was developed. The Rotating Element electric-field Vector (REV) method was applied to it, which measures only the amplitudes of signals at the power-receiving location. Two novel devices have been designed and fabricated to achieve rapid and automated calibration. A Reference Signal Transmitter (RST) enables reliable and rapid phase rotation, replacing one of the radiation elements in an MPT module. A Calibration Signal Detector (CSD) measures the synthesized waveform of the reference channel and the tested channel signal at the wireless power receiving location. The system’s operation was verified in the laboratory by measuring the combined signal of the reference and under-test channels of the modified MPT module. The hardware of the proposed remote array calibration system was installed to an active wireless power transmission (WPT) system with 96 radiation elements of 5.8 GHz. The calibration software was integrated with the control program of the WPT system. The entire MPT array was successfully calibrated using the CDS at a distance of 58 m. The entire calibration process could be completed within 3 minutes using Ethernet wired communication and 4 minutes using 922 MHz wireless communication. Decreased beam width and increased power density were confirmed after the calibration.