Analysis of Received Power in RF Wireless Power Transfer System With Array Antennas

Chan Mi Song,Jongseok Bae,Kang-Yoon Lee,Sang-Hwa Yi,Youngoo Yang,Son Trinh-Van,Keum Cheol Hwang

doi:10.1109/access.2021.3083270

Abstract

In this paper, a method for calculating the received power in a radio-frequency wireless power transfer system with array antennas is proposed. The received power is derived based on the superposition of the electric fields that radiate from individual transmitter (Tx) elements and are captured by each receiver (Rx) element. That is expressed in a finite series form with the radiation patterns of an element considering mutual coupling in the array and corresponding distances between the elements of Tx and Rx. Unlike conventional methods (such as the Friis and Goubau formulas), this approach is able to calculate the received power precisely in both Fresnel and far-field regions. It is also efficiently applicable to various cases, such as those involving beamforming and with varying positions of Rx. The calculated results using this method are applied to a 5.2 GHz WPT system with array antennas and verified through comparisons with both simulation and experimental results.

Highlights

W ireless power transfer (WPT) technology has been used recently in various applications, such as mobile devices, wearable devices, implantable medical devices, and electrical vehicles
RF WPT technology based on beamforming enables immediate responses to changes in the position of Rx and transmits the wireless power to a number of devices with a single Tx system. This is why it is suitable for charging various low-power devices and is utilized for wireless sensor networks (WSNs) with Internet of things (IoT) devices [11]–[16]
In this paper, a method by which to calculate the received power and WPT efficiency based on wireless power interactions between individual Tx and Rx array elements in a WPT system with array antennas is investigated

Summary

INTRODUCTION

W ireless power transfer (WPT) technology has been used recently in various applications, such as mobile devices, wearable devices, implantable medical devices, and electrical vehicles. As when calculating (9) for the case of Fig. 4, the radiation patterns applied to the calculation consider the mutual coupling of the each array element (Tx: patch, Rx: dipole) In these cases, the results of the proposed calculation method are in good agreement with the EM simulation results, much more than the conventional calculation method. Regardless of the type or number of array antennas, it can be seen that the proposed calculation method is useful for analyzing various WPT scenarios

BEAMFORMING

Findings

CONCLUSION