Additive manufacturing using direct-write or screen printing represent low-waste methods for fabricating antennas on low-cost flexible substrates. To realize rectennas using low-resolution printing methods, high-impedance antennas with simple printable geometries are required. This article proposes an electrically-small ( 0.212×0.212λ20.212\times 0.212\lambda ^{2} ) folded dipole antenna design with a scalable impedance for directly matching energy harvesting rectifiers. The antenna is demonstrated in a high-efficiency sub-1 GHz rectenna, with varying mesh fill-factors for optical transparency. The proposed solid (non-transparent) and meshed (70%-transparent) rectennas achieve a Power Conversion Efficiency (PCE) of over 70% and 60% from sub- 1 μW1~\mu \text{W} /cm2 power densities, at 940 and 920 MHz, respectively. This represents a 37% improvement in the PCE over state-of-the-art flexible rectennas while maintaining the smallest electrical size and simplest design by not requiring a matching network. The 70%-transparent rectenna’s performance is investigated in real-life use-cases showing its suitability for ambient RF energy harvesting with over 500 mV DC output from a phone-call.

中文翻译：

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针对增材制造进行优化的网状高阻抗匹配无网络整流天线


使用直写或丝网印刷的增材制造代表了在低成本柔性基板上制造天线的低浪费方法。为了使用低分辨率印刷方法实现整流天线，需要具有简单可印刷几何形状的高阻抗天线。本文提出了一种电小（ 0.212×0.212λ20.212\times 0.212\lambda ^{2} ）折叠偶极子天线设计，具有可扩展的阻抗，可直接匹配能量收集整流器。该天线在高效低于 1 GHz 的整流天线中进行了演示，具有不同的网格填充因子以实现光学透明度。所提出的固体（不透明）和网状（70% 透明）整流天线可在低于 1 μW1~\mu \text{W} /cm2 的功率密度下实现超过 70% 和 60% 的功率转换效率（PCE），分别为 940 和 920 MHz。这意味着 PCE 比最先进的柔性整流天线提高了 37%，同时由于不需要匹配网络而保持了最小的电气尺寸和最简单的设计。 70% 透明整流天线的性能在现实生活中的使用案例中进行了研究，显示其适合通过电话呼叫输出超过 500 mV 的直流电来收集环境射频能量。