Sun Zhenci, Zhao Xiaoguang, Zhang Lingyun, Mei Ziqi, Zhong Han, You Rui, Lu Wenshuai, You Zheng, Zhao Jiahao
Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Precision Testing Technology and Instruments, Tsinghua University, Beijing 100084, China.
Sensors (Basel). 2022 Aug 30;22(17):6523. doi: 10.3390/s22176523.
WiFi energy harvesting is a promising solution for powering microsensors and microsystems through collecting electromagnetic (EM) energies that exist everywhere in modern daily lives. In order to harvest EM energy, we proposed a metamaterial-inspired antenna (MIA) based on the resonant magnetic dipole operating in the WiFi bands. The MIA consists of two metallic split-ring resonators (SRRs), separated by an FR4 dielectric layer, in the broadside coupled configuration. The incident EM waves excite surface currents in the coupled SRRs, and the energy is oscillating between them due to near-field coupling. By varying the vertical distance of the two SRRs, we may achieve impedance matching without complicated matching networks. Collected EM energy can be converted to DC voltages via a rectifier circuit at the output of the coupling coil. Measured results demonstrate that the designed MIA may resonate at 2.4 GHz with a deep-subwavelength form factor (14 mm×14 mm×1.6 mm). The WiFi energy-harvesting capability of the proposed MIA with an embedded one-stage Dickson voltage multiplier has also been evaluated. A rectified DC voltage is approximately 500 mV when the MIA is placed at a distance of 2 cm from the WiFi transmit antenna with a 9 dBm transmitting power. The proposed compact MIA in this paper is of great importance for powering future distributed microsystems.
通过收集现代日常生活中无处不在的电磁（EM）能量，WiFi能量采集是为微传感器和微系统供电的一种很有前景的解决方案。为了采集EM能量，我们提出了一种基于在WiFi频段工作的谐振磁偶极子的超材料启发天线（MIA）。该MIA由两个金属开口环谐振器（SRR）组成，它们由一个FR4介电层隔开，采用宽边耦合配置。入射的EM波在耦合的SRR中激发表面电流，并且由于近场耦合，能量在它们之间振荡。通过改变两个SRR的垂直距离，我们可以在不使用复杂匹配网络的情况下实现阻抗匹配。收集到的EM能量可以通过耦合线圈输出端的整流电路转换为直流电压。测量结果表明，所设计的MIA可以在2.4 GHz频率下谐振，具有深亚波长外形尺寸（14 mm×14 mm×1.6 mm）。还评估了所提出的带有嵌入式单级迪克森电压倍增器的MIA的WiFi能量采集能力。当MIA放置在距离WiFi发射天线2 cm处且发射功率为9 dBm时，整流后的直流电压约为500 mV。本文所提出的紧凑型MIA对于为未来的分布式微系统供电具有重要意义。
