Passing through the transformation of wood to coal then to oil and gas, we find ourselves fortunate to witness the next major transformation, which will lead us to the “New Energy Era.” Due to advancements in the field of electronics, energy harvesting has attracted great attraction from researchers and scientists to enhance portability and reliability with reduction in battery wastes. Moreover, wearable electronic devices are also becoming quite popular these days because of their usage in a broad range of applications like sports, health sciences, emergency, and so forth. In order to make sure smooth operation and to increase the working time span of these devices, it has become really important to bring wearable devices and radio frequency (RF) energy harvesting to the same platform. RF energy harvesting is one of the best suitable technology for wearable devices. The abundance of RF energy in surroundings and the ability of RF signal to penetrate buildings play an important role to empower wearable devices. One of the major challenges is to improve power conversion efficiency of wearable rectenna for energy harvesting due to requirements of less efficient bio-compatible materials for such antennas with conformability issues. This article mainly aims to present different wearable rectenna design techniques, reported over the years. It also presents a tabular comparison of rectenna performance in terms of power conversion efficiency and gains for diverse frequency bands, substrate materials, and conducting materials. In addition, this article also includes the challenges and obstacles in designing an efficient RF energy harvesting rectenna for wearable devices.

中文翻译：

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射频能量收集与可穿戴设备的结合：整流天线设计综述

通过木材到煤炭再到石油和天然气的转变，我们发现自己有幸见证下一次重大变革，这将引领我们进入“新能源时代”。由于电子领域的进步，能量收集吸引了研究人员和科学家的极大兴趣，以提高便携性和可靠性并减少电池浪费。此外，可穿戴电子设备如今也变得非常流行，因为它们在体育、健康科学、急救等广泛应用中得到了广泛使用。为了确保这些设备的平稳运行并增加工作时间跨度，将可穿戴设备和射频 (RF) 能量收集带到同一平台变得非常重要。射频能量收集是最适合可穿戴设备的技术之一。周围环境中丰富的射频能量和射频信号穿透建筑物的能力对赋能可穿戴设备起着重要作用。主要挑战之一是提高用于能量收集的可穿戴整流天线的功率转换效率，因为此类天线需要效率较低的生物相容性材料，但存在整合性问题。本文主要旨在介绍多年来报道的不同可穿戴整流天线设计技术。它还以表格形式比较了整流天线在不同频带、基板材料和导电材料的功率转换效率和增益方面的性能。此外，