This paper discusses the design and fabrication of a low-profile Hilbert-shaped metamaterial (MTM) array-based antenna, forming a rectangular patch with partial ground plane backing; the rest is slotted with traces for RF energy harvesting. The antenna is mounted on a 28 mm × 32 mm indium nickel oxide polymerized palm fiber (INP) substrate and compared to the identical one based on FR4 substrate. The two prototypes are printed with silver nanoparticles. Numerical and experimental tests are applied to the antenna performance in terms of S11 and radiation patterns. The obtained antenna gain bandwidth product of the INP prototype is found to be significantly better than the FR4 prototype. The proposed INP antenna gain at 5.8 and 8 GHz frequencies is found to be about 4.56 and 7.38 dBi, respectively, while the FR4 antenna gain is found to be 4.56 and 6.85 dBi at 5.8 and 8 GHz, respectively. Finally, the resultant DC voltage and the efficiency of conversion from harvested RF energy are measured experimentally at 5.8 and 8 GHz for both proposed prototypes.

中文翻译：

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在氧化铟镍聚合棕榈纤维基板上进一步实现基于柔性超材料的天线，用于射频能量收集

本文讨论了基于低剖面希尔伯特形超材料 (MTM) 阵列的天线的设计和制造，形成了带有部分接地平面背衬的矩形贴片；其余部分带有用于射频能量收集的迹线。该天线安装在 28 mm × 32 mm 氧化铟镍聚合棕榈纤维 (INP) 基板上，并与基于 FR4 基板的相同天线进行了比较。这两个原型都印有银纳米粒子。数值和实验测试应用于天线性能方面小号11和辐射模式。发现 INP 原型获得的天线增益带宽积明显优于 FR4 原型。建议的 INP 天线增益在 5.8 和 8 GHz 频率下分别约为 4.56 和 7.38 dBi，而 FR4 天线增益在 5.8 和 8 GHz 下分别为 4.56 和 6.85 dBi。最后，在 5.8 和 8 GHz 频率下，对两个提议的原型进行了实验测量所得直流电压和从收集的射频能量转换的效率。