Wireless power transmission and energy harvesting techniques could be used to power and operate devices in, on and around the human body. However, near-field power transmission approaches are limited by distance, and the efficiency of far-field radiofrequency methods is limited by the body shadowing effect. Here, we show that the body-coupling characteristics of electromagnetic waves—which are either artificially introduced or present in the immediate surroundings—can be used to enable a power transmission and energy harvesting method that offers power to locations all around the body. The body-coupled power transmission exhibits a path loss 30- to 70-dB lower than far-field radiofrequency transmission in the presence of body shadowing. The system can recover 2 µW at the head from an ~1.2-mW transmitter placed 160 cm away at the ankle. In the absence of an active power transmitter, we demonstrate placement-independent scavenging of ambient electromagnetic waves coupled onto the human body, resulting in a power recovery of ~2.2 µW from electromagnetic waves of up to −10-dBm on the body.

无线电力传输和能量收集技术可用于为人体内部、人体上和周围的设备供电和操作。然而，近场功率传输方法受到距离的限制，远场射频方法的效率受到身体阴影效应的限制。在这里，我们展示了电磁波的身体耦合特性（人工引入或存在于周围环境中）可用于实现电力传输和能量收集方法，为身体周围的位置提供电力。在存在身体阴影的情况下，身体耦合功率传输的路径损耗比远场射频传输低 30 到 70 dB。该系统可以从距脚踝 160 厘米处的约 1.2 毫瓦发射器在头部恢复 2 微瓦。