EAGER: Development of a rectenna for energy harvesting and detection applications

对太阳能利用的日益增长的兴趣已经显著地刺激了在光生伏打领域中的研究，尽管大多数PV器件仍然限于约20%至30%的最大转换效率。与大多数其他能量收集装置相比，已发现整流天线的功率转换效率在2.45GHz下大于85%。整流天线基本上是一种天线，它捕获电磁辐射并通过整流器（二极管）将其转换为直流电（DC）。由于缺乏可以在可见光和近红外（IR）范围内的高太阳辐射频率下整流的二极管，可以设计一种更实用的整流天线，首先捕获太阳辐射，然后使用创新的频率选择发射器将其转换为~30 THz范围内的IR。一旦能量被缩小到~ 30 THz频率范围，就可以使用使用量子隧穿机制操作的二极管进行整流。金属-绝缘体-金属（MIM/MIIM）二极管的整流特性可用于能量转换装置或检测器中，其中检测器使用外部电路来放大整流信号，并且能量收集器使用整流信号作为可用功率。在成功演示工作整流天线之后，并且由于整流天线的卷对卷制造所需的廉价且广泛可用的材料，（每瓦几美分）整流天线太阳能模块将是可以实现的。该研究项目解决了两个主要的科学障碍，阻止在太赫兹频率范围内开发工作的整流天线：（a）等离子体激元发射器将被设计成选择性地发射以天线的工作频率（~ 30 THz）为中心的辐射。仔细选择的周期性光栅和合适的材料的尺寸将用于设计发射器，以选择性地在感兴趣的频率周围发射。(b)将制造具有MIM/MIIM配置的隧道二极管以整流由纳米天线捕获的辐射。成功的二极管需要在底部金属表面上沉积均匀且无针孔的共形单层绝缘体。此外，还将开发一种二极管，该二极管可以具有更高程度的不对称性、灵敏度和急剧的导通电压。具有多个绝缘层的共振隧穿二极管可以表现出非线性和非对称的I-V特性，这使得它们非常适合于高频整流目的。这种MIM/MIIM二极管将具有THz开关能力，同时保持低电阻以匹配天线阻抗。纳米天线阵列和制造的整流器可用于能量收集和检测应用。该计划将整合研究和教育，并促进各级的教学，培训和学习，用于能量收集和探测器中的整流天线应用。

Growing interest in the utilization of solar energy has significantly stimulated research in the field of photovoltaics, although most PV devices are still limited to maximum conversion efficiencies of about 20% to 30%. The power conversion efficiency of a rectenna, in contrast to most other energy harvesting devices, has been found to be greater than 85% at 2.45GHz. A rectenna is basically an antenna that captures electromagnetic radiation and converts it to direct current (DC) through a rectifier (diode). Because of the lack of diodes that can rectify at high solar radiation frequencies in the visible and near infra-red (IR) range, a more practical rectenna can be designed that first captures the solar radiation and then converts it to IR in the ~30 THz range using an innovative frequency selective emitter. Once the energy has been downscaled to ~30THz frequency range, it can be rectified using diodes that operate using the quantum tunneling mechanism. The rectification property of metal-insulator-metal (MIM/MIIM) diodes could be used in energy conversion devices or detectors, where the detectors use external circuits to amplify the rectified signal and the energy harvesters use the rectified signal as usable power. Upon the successful demonstration of a working rectenna and because of inexpensive and widely available materials needed for the roll-to-roll manufacturing of rectennas, very high efficiency and low cost (few cents per watt) rectenna solar modules would be achievable.This research project addresses the two major scientific obstacles preventing the development of a working rectenna at the THz frequency range: (a) Plasmonic emitters will be designed to selectively emit radiation centered around the working frequency of the antenna (~30THz). Carefully chosen dimensions of periodic gratings and suitable materials will be used to design an emitter to selectively emit around the frequency of interest. (b) Tunnel diodes with MIM/MIIM configurations will be fabricated to rectify the radiation captured by the nanoantenna. The deposition of a conformal monolayer of uniform and pinhole free insulator(s) onto the bottom metal surface is required for a successful diode. In addition, a diode will be developed that can have a higher degree of asymmetry, sensitivity and sharp turn-on voltage. Resonant tunneling diodes with multiple insulating layers can exhibit nonlinear and asymmetric I-V characteristics which makes them well suited for rectification purposes at high frequencies. Such MIM/MIIM diodes will have THz switching capability while maintaining low resistance to match the antenna impedance. An array of nanoantennas and fabricated rectifiers can be used in energy harvesting and detection applications. The program will integrate research and education and promote teaching, training and learning at all levels for rectenna applications in energy harvesting and detectors.