一种射频能量捕获网络移动能量源均衡化充电策略

为解决传统电池供电传感器网络存在的电池不易更换、节点能量容易耗尽等问题,射频能量捕获技术已逐步应用于无线可充电传感器网络中.由于不同位置传感器节点的工作负荷不同,捕获能量也有差异,实现节点能量的均衡化分布可以有效地提高节点的存活率.考虑射频能量源移动充电的场景,在已知节点位置信息的条件下,设计合理均衡的路由方案和充电算法.首先将区域基于蜂窝六边形网格划分,分别对网格和节点分层,提出逐层传输的均衡式路由策略,然后给出无线充电小车的移动路径,对相邻两层内节点剩余能量的方差最小化问题建模,由内层向外层依次确定能量源在各停留点的充电时间.仿真结果表明,相比已有的均衡化充电方法,该策略可以明显提高节点剩余能量的均衡性,从而延长网络的生命周期.     

Realization of Flexible Plasma Display Panels on PET Substrates

DC plasma display panels are fabricated on flexible polyethylene terephtalate (PET) substrates. Each pixel consists of laterally placed anode and cathode electrodes. All electrical elements are formed on a single PET substrate, whereas a second substrate is needed to encapsulate the panel. Silver is used as the metal for each electrode and standard photolithography is used to form each cell. A 150-/spl mu/m-thick layer of a UV-curable polymeric adhesive was used to form barrier ribs to both electrically isolate neighboring cells and to encapsulate the plasma. Conversion of vacuum UV into visible light is possible by blast-embedding of proper phosphor grains into the top substrate. The current-voltage and turn-on voltage versus pressure characteristics are examined. Effect of curvature on turn-on voltage is addressed.     

Modal Analysis of Microstrip Antenna on Fiber Reinforced Anisotropic Substrates

In this communication, microstrip antenna on fiber reinforced anisotropic substrates has been considered in aerospace applications; however, the antenna's optical axis may not necessarily be colinear with any of the substrate's principal axes and that leads to a nondiagonal permittivity matrix (tensor). This work extends the studies of microstrip antenna on isotropic substrate and on uniaxial substrate to analyze antenna performance on fiber reinforced anisotropic substrates, where the permittivity matrix has five dielectric constants because of the substrate's fiber direction. The solution is based on modal analysis so that the wave immittance can be derived in a closed form. Analyses and experimental verification show that the antenna performance is strongly influenced not only by the permittivity along the principal axes but also by the fiber direction of the substrate.     

射频能量捕获传感网移动能量源的布置策略研究

射频能量捕获传感网（RF Energy Harvesting Wireless Sensor Network,RFEH-WSN）由专用射频能量源设备（Energy Transmitter,ET）和具有射频能量捕获功能的传感器节点（Energy Harvesting Recevier,简称EHR）组成.该网络解决了传感器网络中电池不易更换与节点能量容易耗尽的问题,使得RFEH-WSN应用前景更加广阔.RFEH-WSN应用中一个值得研究的问题是如何布置ET的充电位置,降低ET能耗且提高覆盖率.已有的工作主要考虑ET布置中单目标优化问题,如最小充电时间、最小功耗、最大覆盖率等.本文以时间最小和覆盖率最大为目标建立多目标优化模型,并提出利用粒子群算法（Particle Swarm Optimization,PSO）求解多目标函数（Multiple Object Program,MOP）的低复杂度近似算法,获得了最优Pareto解集.仿真结果表明,多目标优化可以满足不同情况的需求,提高充电效用.     

柔性透明导电氧化物薄膜的制备及其应用

柔性透明导电氧化物薄膜以其重量轻、不易碎、成本低等独特的优点而备受青睐,在塑料液晶显示、可折叠太阳能电池等领域得到广泛的应用.文章介绍了目前制备柔性透明导电氧化物薄膜的主要技术及其优缺点,总结了近年来对柔性衬底的处理方法,最后对柔性透明导电氧化物薄膜在各个领域的开发应用和未来的重点研究方向进行了展望.     

Optimization of a Novel Rectenna for RF Energy Harvesting at 2.45 GHz

In this work, the different elements of a rectenna were optimized for the energy harvesting from Wi-Fi at 2.45 GHz, using the particle swarm optimization method with real or hybrid dimensions depending on the element. The antenna was optimized in different steps and for each one the effect on its performance was determined. For the rectifier, several commercial diodes were compared for evaluating the best selection for this application. Additionally, a low pass filter and an impedance matching of L-section were implemented as coupling elements. The antenna from the novel rectenna had a gain equal to 4.42 dBi due to the incorporation of a pixeled metasurface structure in the ground layer, and a maximum conversion efficiency of 73% with the diode SMS-7630. In this sense, the optimized rectenna presented a better performance than others from the literature for RF energy harvesting at 2.45 GHz. Therefore, the proposed rectenna can be a good alternative as a power supply in nodes of wireless sensor networks with the addition of the DC–DC boost converter LTC3105.

     

射频/微波能量收集系统的整流电路研究进展

射频/微波能量收集系统以可持续、环保等优点在无线传感器网络、可穿戴设备等领域具有广泛应用前景。对近年来射频/微波能量收集系统的整流电路的研究进展进行了概述。分析并讨论了整流电路的技术指标和电路结构,分别从器件研究和电路设计两个方面对整流电路的研究进展进行分析、归纳。从原理、性能提升等方面分析具有低的零偏压电阻值的自旋二极管应用于微瓦量级信号整流电路的潜力;从微弱信号整流、宽输入功率范围信号整流、高功率转换效率整流、阻抗去敏感化4个方面分析了整流电路设计的关键问题,归纳出有效的解决途径并对整流电路的发展趋势进行了展望。     

An Efficient 2.45 GHz Spiral Rectenna Without a Matching Circuit for RF Energy Harvesting

Wireless Personal Communications - This paper presents an efficient spiral rectenna to be used for radio frequency energy harvesting application. This rectenna is simple, low cost and an efficient...     

A Low-Power Stand-Alone Adaptive Circuit for Harvesting Energy From a Piezoelectric Micropower Generator

An adaptive energy-harvesting circuit with low power dissipation is presented and demonstrated, which is useful for efficient ac/dc voltage conversion of a piezoelectric micropower generator. The circuit operates stand-alone, and it extracts the piezoelectric strain energy independent of the load and piezoelectric parameters without using any external sensor. The circuit consists of a voltage-doubler rectifier, a step-down switching converter, and an analog controller operating with a single supply voltage in the range of 2.5–15 V. The controller uses the piezoelectric voltage as a feedback and regulates the rectified voltage to adaptively improve the extracted power. The nonscalable power dissipation of the controller unit is less than 0.05 mW, and the efficiency of the circuit is about 60% for output power levels above 0.5 mW. Experimental verifications of the circuit show the following: 1) the circuit notably increases the extracted power from a piezoelectric element compared to a simple full-bridge diode rectifier without control circuitry, and 2) the efficiency of the circuit is dominantly determined by its switching converter. The simplicity of the circuit facilitates the development of efficient piezoelectric energy harvesters for low-power applications such as wireless sensors and portable devices.      

A Self-Healing Triboelectric Nanogenerator Based on Feathers for Sensing and Energy Harvesting

A useful direction to solve the energy problem is the effective repeated use of biomaterial for mechanical energy collection and sensing applications. Here, a feather-based single-electrode triboelectric nanogenerator (F-STENG) by only sputtering copper atoms on the feathers are presented. The feather of F-STENG, as a natural material, has environmental friendliness, which is different from the polymer materials of other triboelectric nanogenerators. F-STENG has super durability due to its feather structure self-healing property. The device has a high output voltage of 90 V and an output current of 3.5 µA. After breaking and self-healing lots of times, the output performance is also 80% of the original. F-STENG has a high sensitivity to temperature, humidity, and wind speed, and the sensitivity is 0.50 V °C⁻¹, -0.98 V RH⁻¹, and 1.67 μA m⁻¹ s⁻¹. The output power of F-STENG is 0.62 mW g⁻¹, which can realize global positioning and photographing to solve the module energy consumption problem. F-STENG provides an effective way for the application of self-powered sensors and equipment in military, industrial, transportation, and daily life.     

利用环境电磁波为无线传感器节点供电新方案

采用无线传感器节点的环境电磁波能量获取关键技术,设计了一种可行的供电方案.通过对所处环境的频谱能量分析和采用合适的天线及转换电路,收集到足够能量驱动节点工作.同时设计了带有唤醒机制的低功耗电源管理电路,以适应节点在环境电磁波能量较少地区的工作.通过获取能量稳定性、有效工作范围和传感器节点的性能相关测试和分析,验证了方案...     

基于压电材料的振动能量回收技术现状综述

随着微机电系统(MEMS)技术的迅猛发展,基于压电振动的能量回收技术可以为MEMS提供电能,受到国内外众多学者的关注。该文介绍了压电式振动能量回收装置的工作机理;分别从能量回收装置的结构和材料、能量转化的接口电路、能量的存储技术、能量回收的应用实例等方面系统的介绍国内外的主要研究成果和研究进展;并对压电振动能量回收技术的发展方向进行了预测。     

A Multi-Layer Stacked Triboelectric Nanogenerator Based on a Rotation-to-Translation Mechanism for Fluid Energy Harvesting and Environmental Protection

Energy shortage and environmental degradation are two important challenges facing humanity. Here, a multi-layer stacked triboelectric nanogenerator (MLS-TENG) based on a rotation-to-translation mechanism is reported for fluid energy harvesting and environmental protection. The mechanism transforms fluid-induced rotation into a reciprocal translation of the MLS-TENG, enabling the conversion of fluid energy into electrical energy. In addition, benefiting from a multi-layer stacked structural design, the open-circuit voltage is increased from 860 to 2410 V and an efficient energy harvesting rate of 2 mJ min⁻¹ is obtained in an actual river. Furthermore, with the assistance of the MLS-TENG, a self-powered wireless temperature and humidity monitoring system and a metal anticorrosion system are successfully established. Ambient monitoring data can be transmitted continuously at an interval of 49.7 s, and the corrosion rate of steel is significantly slowed down. This study provides guidance for efficient harvesting of ambient fluid energy, with promising applications in environmental monitoring and protection.     

Ferroelectric Polarization-Enhanced Performance of Flexible CuInP2S6 Piezoelectric Nanogenerator for Biomechanical Energy Harvesting and Voice Recognition Applications

2D piezoelectric materials have strong intrinsic piezoelectricity and superior flexibility, which are endowed with huge potential to develop piezoelectric nanogenerators (PENGs). However, there are few attempts to investigate the energy harvesting of 2D ferroelectric materials. Herein, an enhanced output performance is reported by ferroelectric polarization in a PENG with exfoliated 2D ferroelectric CuInP₂S₆ (CIPS). Specifically, the polarized CIPS-based PENG produces a short-circuit current of 760 pA at 0.85% tensile strain, which is 3.8 times higher than that of unpolarized CIPS-based PENG. Systematical PFM and Raman analysis reveal that the ferroelectric polarization remarkably reinforces the effective piezoelectric constant of CIPS nanoflakes and boosts the in-plane migration and out-of-plane hopping of copper ions, which is the main reason for the enhancement of output performance. Furthermore, the CIPS-based PENG can not only be utilized to harvest biomechanical energy such as wrist joints movement, but also exhibits a potential for a voice recognition system integrated with deep learning technology. The classification accuracy of a series of letter sounds is as high as 96%. This study commendably broadens the application scope of 2D materials in micro-nano energy and intelligent sensors, which will have profound implications for exploring wearable nanoelectronic devices.     

一种基于缝隙结构的小型双频段射频能量接收天线

随着超低功耗芯片技术的发展,无线传感器节点的功耗已进入微瓦（μW）级范围,使低功耗传感器利用周围环境中的射频无线能量为自身供电成为可能。提出了一种用于无线传感器节点的小型射频能量接收天线。该天线采用微带缝隙结构,基于缝隙天线设计理论,应用全波电磁场工具对其进行了设计及仿真优化,并获得了该结构谐振点随尺寸变化的一般规律。在常用FR4材料的小尺寸双面PCB板上,通过开槽加载和微带线馈电方法使天线可以同时工作在GSM和ISM两个频段。在1．9GHz和2．4CHz频率点上,天线的回波损耗分别为-39．4dB和-20．8dB,最大增益分别达到1．4dBi和2．9dBi,测试与仿真结果基本吻合。该天线含地平面在内的尺寸为5cm×5cm,实现成本低,可同时接收两个频段的射频能量,有效地扩展了频率适应范围,提高了能量接收效率。     

Influence of Oxygen Content on the Physical and Electrical Properties of Thin Yttrium Oxide Dielectrics Deposited by Reactive RF Sputtering on Si Substrates

This paper describes the physical properties and electrical characteristics of thin Y₂O₃ gate oxides grown on silicon substrates through reactive radiofrequency (RF) sputtering. The structural and morphological features of these films were studied using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy. We found that the Y₂O₃ gate film prepared under an argon-to-oxygen flow ratio of 25:5 and annealed at 700°C exhibited a reduced equivalent oxide thickness, gate leakage current, interfacial density of states, and hysteresis voltage; it also showed an increased breakdown voltage. We attribute this behavior to (1) the optimum oxygen content in the metal oxide film preventing amorphous silica or silicate from forming at the Y₂O₃/Si interface and (2) the low surface roughness. These materials also exhibit negligible degrees of charge trapping at high electric field stress.     

一种射频功放稳压电源的设计与实现

介绍了一种大功率射频稳压电源的组成及工作原理，经出了详细的设计电路，该电源能满足超短波电台大功率功放电路的使用要求。     

High Performance Flexible Lithium-Ion Battery Electrodes: Ion Exchange Assisted Fabrication of Carbon Coated Nickel Oxide Nanosheet Arrays on Carbon Cloth

Transition metal oxides (TMOs)-based anode materials of high theoretical capacities have been intensively studied for lithium-ion storage. However, their poor high-rate capability and cycling stability remain to be effectively resolved. Herein, a novel ion exchange (IE)-assisted indirect carbon coating strategy is proposed to realize high performance freestanding TMO-based anodes for flexible lithium-ion batteries (FLIBs). This approach effectively avoids the possible side reaction of oxide reduction, enhances degrees of graphitization of the carbon coating, and preserves advantageous nanostructure of the starting template, leading to enhanced electrical conductivities, alleviated volume variation induced structural instability, fast lithium-ion diffusion pathways and enhanced electron transfer kinetics. As a proof of concept, IE-prepared carbon coated NiO nanosheet arrays with excellent structural and electrochemical stability are developed as freestanding anodes for LIBs and FLIBs, which exhibit outstanding electrochemical performances superior to most state-of-the-art NiO-based anodes reported in recent years. The product anode delivers a high areal capacity (3.08 mAh cm⁻² at 0.25 mA cm⁻²), outstanding high-rate capability (1.78 mAh cm⁻² at 8 mA cm⁻²) and excellent cycling stability (over 300 cycles). Further pouch cell tests confirm the excellent flexibility of the freestanding electrode against mechanical deformation with well-maintained electrochemical performance under folding.     

In Situ Thermolysis of a Ni Salt on Amorphous Carbon and Graphene Oxide Substrates

Understanding the thermal decomposition of metal salt precursors on carbon structures is essential for the controlled synthesis of metal-decorated carbon nanomaterials. Here, the thermolysis of a Ni precursor salt, NiCl₂·6H₂O, on amorphous carbon (a-C) and graphene oxide (GO) substrates is explored using in situ transmission electron microscopy. Thermal decomposition of NiCl₂·6H₂O on GO occurs at higher temperatures and slower kinetics than on a-C substrate. This is correlated to a higher activation barrier for Cl₂ removal calculated by the density functional theory, strong Ni-GO interaction, high-density oxygen functional groups, defects, and weak van der Waals using GO substrate. The thermolysis of NiCl₂·6H₂O proceeds via multistep decomposition stages into the formation of Ni nanoparticles with significant differences in their size and distribution depending on the substrate. Using GO substrates leads to nanoparticles with 500% smaller average sizes and higher thermal stability than a-C substrate. Ni nanoparticles showcase the fcc crystal structure, and no size effect on the stability of the crystal structure is observed. These findings demonstrate the significant role of carbon substrate on nanoparticle formation and growth during the thermolysis of carbon–metal heterostructures. This opens new venues to engineer stable, supported catalysts and new carbon-based sensors and filtering devices.