Feedback Simplification Scheme for Wireless Power Transfer Systems
                        Based on Beamforming with Phased Array Antenna

Retrodirectivity have several important applications in communication and in wireless power transfer. In this paper, frequency sensitive retrodirective transceiver is proposed. It receives a signal and infers its direction from its frequency spectrum, then it can transmit a new signal back to the same or other direction at the designer wish. To determine the direction of the coming signal, a 0.85-1.15GHz frequency scanning phased array antenna is used so that the received signal would have a distorted spectrum with the maximum amplitude frequency component linked to the direction of the signal. Based on the frequency scanning, the retrodirectivity system can be used for wireless power transfer or for reactive jamming. Special circuit is designed to receive the signal with strongest power and to isolate the frequency component with maximum amplitude. Phase-locked loop (PLL) circuit is used to link such frequency to specific phase shift that is introduced to the transmitter array antenna to send a new signal to the same direction of the received signal. ADS simulation is performed to demonstrate the performance of each block.

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Wireless Power Transfer to a Microaerial Vehicle with a Microwave Active Phased Array

International Journal of Antennas and Propagation ◽

10.1155/2014/374543 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Shotaro Nako ◽

Kenta Okuda ◽

Kengo Miyashiro ◽

Kimiya Komurasaki ◽

Hiroyuki Koizumi

Keyword(s):

Phased Array ◽

Wireless Power Transfer ◽

Axial Ratio ◽

Input Power ◽

Power Transfer ◽

Wireless Power ◽

Phased Array Antenna ◽

Power Fluctuation ◽

Microwave Beam ◽

Yaw Angle

A wireless power transfer system using a microwave active phased array was developed. In the system, power is transferred to a circling microaerial vehicle (MAV) by a microwave beam of 5.8 GHz, which is formed and directed to the MAV using an active phased array antenna. The MAV is expected to support observation of areas that humans cannot reach. The power beam is formed by the phased array with eight antenna elements. Input power is about 5.6 W. The peak power density at 1,500 mm altitude was 2.63 mW/cm2. The power is sent to a circling MAV. Therefore, the transfer beam should be polarized circularly to achieve a constant power supply independent of its yaw angle. To minimize the polarization loss, a sequentially routed antenna (SRA) was applied to the transmitter antenna. Results show that the axial ratio of 0.440 dB was accomplished and that power fluctuation was kept below 1%.

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Dual-Band RF Wireless Power Transfer System with a Shared-Aperture Dual-Band Tx Array Antenna

Energies ◽

10.3390/en14133803 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3803

Author(s):

Chan-Mi Song ◽

Hong-Jun Lim ◽

Son Trinh-Van ◽

Kang-Yoon Lee ◽

Youngoo Yang ◽

...

Keyword(s):

Wireless Power Transfer ◽

Transmission Efficiency ◽

Array Antenna ◽

Dual Band ◽

Single Frequency ◽

Power Transfer ◽

Wireless Power ◽

Beam Focusing ◽

Received Power ◽

Rf Wireless

In this paper, a dual-band RF wireless power transfer (WPT) system with a shared-aperture dual-band Tx array antenna for 2.4 and 5.8 GHz is proposed. The final configuration of the Tx array, which is made up of 2.4 GHz right-handed circular polarization (RHCP) patches and 5.8 GHz RHCP patches, is derived from the optimization of 2.4 and 5.8 GHz thinned arrays, ultimately to achieve high transmission efficiency for various WPT scenarios. The dual-band RF WPT Tx system including the Tx array antenna and a Tx module is implemented, and Rx antennas with a 2.4 GHz patch, a 5.8 GHz patch, and a dual-band (2.4 and 5.8 GHz) patch are developed. To validate the proposed dual-band RF WPT system, WPT experiments using a single band and dual bands were conducted. When transmitting RF wireless power on a single frequency (either 2.482 GHz or 5.73 GHz), the received power according to the distance between the Tx and Rx and the position of the Rx was measured. When the distance was varied from 1 m to 3.9 m and the transmitted power was 40 dBm, the received power value at 2.482 GHz and 5.73 GHz were measured and found to be 24.75–13.5 dBm (WPT efficiency = 2.985–0.224%) and 19.25–6.8 dBm (WPT efficiency = 0.841–0.050%), respectively. The measured results were in good agreement with the calculated results, and it is revealed that the transmission efficiency when wireless power is transmitted via beam-focusing increases more than that with conventional beam-forming. Furthermore, the dual-band WPT experiment proves that 2.482 GHz beam and 5.73 GHz beams can be formed individually and that their wireless power can be transmitted to a dual-band Rx or two different Rx.

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