The dc power collected by radio frequency energy harvesting (RFEH) absorbing surfaces is limited by their physical aperture. Here, a compact, conformable, and ultrathin sub-1 GHz large-area RFEH surface is proposed based on electrically small ( ka=0.58ka=0.58 ) “wire-type” rectenna elements, with an effective area exceeding its physical aperture size. Using optimized large-signal complex source tuning, the rectifiers achieve up to 36% measured power conversion efficiency (PCE) at =20 dBm. The proposed 15 cm-diameter six-element array generates a 27.5 μW\mu \text{W} at 1 V output from a 0.17 μW0.17~\mu \text{W} /cm2 incident power density across a 40 kΩ\text{k}\Omega load. Owing to its series connection, the voltage output is boosted, and the load resistance dependence is suppressed enabling over 60% of the maximum RF-to-dc PCE to be preserved for loads between 7 and 100 kΩ\text{k}\Omega , with an area-normalized figure-of-merit nearly 100% higher than previous arrays. The proposed array is integrated with a commercial DC-DC converter and demonstrated powering a Bluetooth low energy (BLE) wireless sensor node (WSN) from an unprecedented incident power density of 0.25 μW\mu \text{W} /cm2. A practical demonstration using a commercial 3 W, 915 MHz Powercast source is presented, showing an 11 m operation range with a 1 V output and illustrating the impact of polarization mismatch on the proposed array.

中文翻译：

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具有大有效孔径的薄型柔性射频能量采集整流天线表面，可为无线传感器节点提供亚μW/cm2 供电


射频能量收集 (RFEH) 吸收表面收集的直流功率受到其物理孔径的限制。在此，提出了一种基于电小 (ka=0.58ka=0.58)“线型”整流天线元件的紧凑、舒适且超薄的 1 GHz 以下大面积 RFEH 表面，其有效面积超过其物理孔径尺寸。使用优化的大信号复杂源调谐，整流器在 =20 dBm 时可实现高达 36% 的测量功率转换效率 (PCE)。所提出的 15 cm 直径六元件阵列在 1 V 输出下从 40 kΩ\text 上的 0.17 μW0.17~\mu \text{W} /cm2 入射功率密度生成 27.5 μW\mu \text{W} {k}\欧米茄负载。由于采用串联连接，电压输出得到提升，并且负载电阻依赖性得到抑制，对于 7 至 100 kΩ\text{k}\Omega 之间的负载，可以保留超过 60% 的最大射频转直流 PCE，面积归一化品质因数比以前的阵列高出近 100%。所提出的阵列与商用 DC-DC 转换器集成，并演示了以前所未有的 0.25 μW\mu \text{W} /cm2 的入射功率密度为蓝牙低功耗 (BLE) 无线传感器节点 (WSN) 供电。介绍了使用商用 3 W、915 MHz Powercast 源的实际演示，显示了 1 V 输出的 11 m 工作范围，并说明了极化失配对建议阵列的影响。