Beam-Switching Quasi-Yagi Rectifier Antenna Array for Wireless Power Transfer and Energy Harvesting

In this paper, a quasi-Yagi rectifier antenna array with beam switching function for wireless power transfer and energy harvesting is proposed. The quasi-Yagi rectifier antenna array is consists of four rotationally symmetric quasi-Yagi antenna units, a Wilkinson power divider with graphene switch and a rectifier unit. The quasi-Yagi antenna units are used to collect RF signals in the corresponding directions, the graphene switches in the Wilkins power divider controls the beam direction of the quasi-Yagi antenna units, and the rectifier unit converts the collected RF signals into DC signals. The quasi-Yagi antenna unit (0.81λ0 × 0.52λ0 × 0.012λ0) operates with an impedance bandwidth of 3.42-3.58 GHz (relative bandwidth 4.6%), a maximum gain of 7.81 dBi in the end-fire direction, and a 3-dB beamwidth of 94.8°. The rectifier does not require an impedance matching network and uses only one microstrip to connect the Schottky diode (HSMS-2850) to the load and filter at the back-end of the rectifier, which has an impedance bandwidth of 3.24-3.60 GHz (relative bandwidth 10.5%), and a maximum power conversion efficiency of 69.2% when the input power is 0 dBm.