In this paper, three compact, high-efficiency, gain enhanced antennas, and corresponding rectifiers have been proposed for GSM1800, 3G, and 4G-LTE energy harvesting applications. The inverted L-stub is placed on the ground plane of the monopole antenna to get the desired frequency band of GSM1800 MHz. The feed length variation method has been adopted for the slot antennas to obtain the required frequency of 3G and 4G-LTE cellular bands. The performance of antennas is analyzed with the inverted L-stub, feed length variation, and the reflector distance. The maximum gain achieved with the reflector positioned at a distance of λ/4 from the antenna backside is three times greater than the gain obtained without the reflector. The prototype antennas and rectifiers have been simulated, fabricated, measured various parameters, and compared with the simulation results. The antennas provide more than 82% radiation efficiency and an enhanced gain of greater than 5.6 dB. The peak efficiency of rectifiers of more than 30% has been achieved. The aforementioned three antennas are integrated with their corresponding rectifiers for operating at 1.8, 2.1, and 2.3 GHz frequencies. The proposed rectennas are formidably suitable for the reception of RF power from the cellular bands.

中文翻译：

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具有增强增益的紧凑型高效五面体和四叶形天线，适用于 GSM1800、3G、4G-LTE 能量收集应用

在本文中，针对 GSM1800、3G 和 4G-LTE 能量收集应用提出了三种紧凑、高效、增益增强的天线和相应的整流器。倒置的 L 型短截线放置在单极天线的接地平面上，以获得所需的 GSM1800 MHz 频段。缝隙天线采用馈电长度变化法，以获得3G和4G-LTE蜂窝频段所需的频率。使用倒置 L 型短截线、馈电长度变化和反射器距离来分析天线的性能。将反射器放置在距离为λ/4 从天线背面获得的增益是没有反射器的增益的三倍。对原型天线和整流器进行了仿真、制造、测量各种参数，并与仿真结果进行了比较。天线提供超过 82% 的辐射效率和大于 5.6 dB 的增强增益。整流器峰值效率已达到30%以上。上述三个天线与其相应的整流器集成在一起，可在 1.8、2.1 和 2.3 GHz 频率下工作。所提出的整流天线非常适合从蜂窝频段接收射频功率。