Chargeable object location identification technique for antenna-arrayed RF power emitter using microcontroller-based harmonic reflection detection circuit

In this paper, we proposed a 915 MHz RF power emitter integrated with a 2×2 patch antenna array, four switchable reflection-type phase shifters with I/Q phase output, a harmonic antenna, and a microcontroller Arduino UNO. To achieve auto location identification, we proposed the rechargeable object which will contain a dual-band Yagi-Uda antenna with a diode to rectify the 915 MHz power and to reflect harmonic wave. By receiving the reflected harmonic power from a detection antenna, the reflected power is converted to a DC level to switch the phase shifters into an appropriate control state. From the experimental results, the maximum output DC voltage represents the object location and the switching angle of the power beam can reach ±15°.