A performance predictor of beamforming versus time-reversal based far-field wireless power transfer from linear array

Hong Soo Park,Sun K Hong

doi:10.1038/s41598-021-02244-9

Abstract

For far-field wireless power transfer (WPT) in a complex propagation environment, a time-reversal (TR) based WPT that can overcome the drawbacks of conventional beamforming (BF) by taking advantage of multipath has been recently proposed. However, due to the WPT performance of BF and TR depending on the complexity of the propagation environment, the performance prediction between BF versus TR would be required. We present a detailed and generalized analysis of the recently proposed performance metric referred to as the peak received power ratio (PRPR) for linear array-based WPT. Here, the effectiveness of PRPR is verified via measurement for free space and indoor scenarios. The results demonstrate that PRPR is directly related to the complexity of the propagation environment and the corresponding power transmission capability of BF and TR. That is, the higher the complexity, the greater the value of PRPR and TR outperforms BF with higher peak power given the same average transmit power and vice versa. The mode decision between BF and TR based on PRPR potentially promises efficient far-field WPT even in a dynamic propagation environment.

Highlights

For far-field wireless power transfer (WPT) in a complex propagation environment, a time-reversal (TR) based WPT that can overcome the drawbacks of conventional beamforming (BF) by taking advantage of multipath has been recently proposed
We have recently introduced the concept of a performance predictor for linear array-based BF versus TR WPT by defining a term referred to as the peak received power ratio (PRPR)[22]
In the case of free space, all PRPR values are less than 1, which implies that BF delivers a peak power higher than TR given the same average transmit power

Summary

Introduction

For far-field wireless power transfer (WPT) in a complex propagation environment, a time-reversal (TR) based WPT that can overcome the drawbacks of conventional beamforming (BF) by taking advantage of multipath has been recently proposed. In a complex propagation environment where multiple scatterers and reflectors exist (e.g. indoor), there is a potential limitation of BF that the beam generated by the array could be impaired due to multipath, which makes effective wireless power transmission to a desired location unfeasible To overcome such disadvantages of BF, time-reversal (TR)-based far-field WPT has been recently proposed[12,13,14,15]. Since the power transmission performance between BF versus TR varies depending on the degree of complexity in a given propagation environment, it would be required to selectively utilize BF and TR In this regard, we have recently introduced the concept of a performance predictor for linear array-based BF versus TR WPT by defining a term referred to as the peak received power ratio (PRPR)[22]. The proposed performance metric would provide a reasonable basis for adaptively deciding between BF and TR in a given environment, Scientific Reports | (2021) 11:22743

Methods

Results

Conclusion