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

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.

Influence of Time‐Varying Atmospheric Channel on Time Reversal Spatial Power Combination of Sparse Array on Ground

“…So the TR technique can adaptively compensate for the phase generated by the channel and focus signals. Since the TR technique was introduced into electromagnetics (Lerosey et al., 2004), it has been widely used in the fields of super‐resolution focusing (Ding et al., 2013; Ge et al., 2011; Lerosey et al., 2007), high‐precision positioning (Li, Liu, Zhao, & Hu, 2019; Liang, 2020; Zhou et al., 2014, 2015), wireless power transmission (An et al., 2021; Ku et al., 2016; Li, Liu, Zhang, et al., 2019; Liu et al., 2011; Park & Hong, 2020, 2021; Y. Wang et al., 2021; Yang et al., 2021; Zhao, Yue, et al., 2012), spatial power combination (Q. Chen et al., 2015; Tian, 2019; Z. Wang et al., 2019; Zhong & Liao, 2016), and so on. In addition, Wang's team has also carried out a series of research on TR technology in shaping electromagnetic fields (Z. Chen et al., 2021; Li, Zhao, et al., 2019), wireless communication (Jin et al., 2013; Z. Wang et al., 2019; Zhao et al., 2014), beam‐steering (Zhao, Jin, et al., 2012), and other fields.…”