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[IEEE 2019 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE) - Melacca, Malaysia (2019.11.25-2019.11.27)] 2019 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE) - RF Rectifier with High Efficiency over a Wide Input Power Range Using a Voltage Controlled Switch in a a??Handovera?? Fashion
摘要： Wireless energy transfer gains from the option of receiving power from multiple sources with different power levels. This paper presents a rectifier that maintains good efficiency over a wide input power range at 2.45 GHz frequency using a MOSFET as the voltage controlled switch (VCS). The VCS performs a ‘handover’ function between a low threshold voltage diode and a high breakdown voltage diode in a seamless manner without interrupting power supply to the load. This topology has only so far produced good results at lower frequencies. An L-matching network is used to achieve impedance matching over the input power range at 2.45 GHz with the help of a blocking capacitor acting as a high pass filter. Simulated results show that the rectifier can maintain its RF to DC conversion efficiency above 50% from 3 to 23.8 dBm. A peak efficiency of 73% at 16.6 dBm is also recorded.
关键词： RF rectifier,wireless power transfer,wireless energy harvesting,wide input power,MOSFET switch
更新于2025-09-23 15:21:01
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Silicon nanocrystal hybrid photovoltaic devices for indoor light energy harvesting
摘要： Silicon nanocrystals (SiNCs) featuring size-dependent novel optical and electrical properties have been widely employed for various functional devices. We have demonstrated SiNC-based hybrid photovoltaics (SiNC-HPVs) and proposed several approaches for performance promotion. Recently, owing to the superiorities such as low power operation, high portability, and designability, organic photovoltaics (OPVs) have been extensively studied for their potential indoor applications as power sources. SiNCs exhibit strong light absorption below 450 nm, which is capable of sufficient photocurrent generation under UV irradiation. Therefore, SiNC-HPVs are expected to be preferably used for energy harvesting systems in indoor applications because an indoor light source consists of a shorter wavelength component below 500 nm than solar light. We successfully demonstrated SiNC-HPVs with a PCE as high as 9.7%, corresponding to the output power density of 34.0 mW cm?2 under standard indoor light irradiation (1000 lx). In addition, we have found that SiNC defects working as electron traps influence the electrical properties of SiNCs substantially, a thermal annealing process was conducted towards the suppression of defects and the improvement of the SiNC-HPVs performance.
关键词： Silicon nanocrystals,Power conversion efficiency,Indoor light energy harvesting,Thermal annealing,Hybrid photovoltaics
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Determination of Noise Components in Laser Correlation Spectroscopic Devices for Signal-to-Noise Ratio Estimation
摘要： This paper concerns with a wireless-energy-transfer (WET)-enabled massive multiple-input-multiple-output (MIMO) system with superimposed pilot (SP)-aided channel estimation. Unlike the conventional WET-enabled frame transmission schemes, with the aid of SP, both the uplink (UL) channel estimation and wireless information transmission (WIT) that powered by the downlink (DL) WET can be operated simultaneously, and thus provide the potential for improving the UL achievable throughput. The impact that the SP has on the performance of such a WET-enabled massive MIMO system is mathematically characterized, and the optimal solution, including the SP power-allocation and the ratio of time-allocation between the duration of UL WIT and DL WET, is derived with regard to maximize the UL achievable throughput. Numerical results demonstrate the proposed SP-aided WET technique yields a superior performance than the conventional pilot-only-based schemes.
关键词： wireless information and power transfer,Energy harvesting,massive MIMO,throughput maximization,channel estimation
更新于2025-09-23 15:21:01
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Experimental Observation of Ultrafast THz Absorption Modulation in a Graphene-Based Metasurface
摘要： Magnetorheological (MR) fluid is a widely used smart material due to its outstanding properties. This paper presents the design, development, modeling, and prototype testing of a self-energizing and self-powered MR brake-by-wire system, whose aforementioned capabilities are enabled by brake energy harvesting. The system is composed mainly of a typical T-shaped drum-type MR brake and a wedge mechanism for self-energizing purpose. Into the system, we also install a generator that harvests regenerative energy during braking, thereby creating a self-power capability that cannot be found in common vehicular brake-by-wire systems. Brake torque analysis is conducted, and the braking process is simulated in a MATLAB/Simulink environment. Finite element analysis of the magnetic field, temperature field, and mechanical strength of critical components is carried out. The simulation results are used to optimize design parameters and material selection. Finally, prototypes and a corresponding test rig are established. The experimental results show that only about 30 W of power is required to generate a 315 N·m brake torque and that the regenerative power produced by the generator can be used for braking, thus fulfilling the self-power requirement. The investigation of different wedge angles indicates that considerable self-energizing occurs under a small wedge angle. The findings demonstrate that the brake actuator, which has a relatively small volume, can significantly enlarge brake torque while harvesting brake energy. This feature enables the promising application of MR fluids in automotive brake systems.
关键词： magnetorheological (MR),wedge mechanism,energy harvesting,Brake-by-wire system,self-powered capability
更新于2025-09-23 15:21:01
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A CMOS-Based Energy Harvesting Approach for Laterally Arrayed Multibandgap Concentrated Photovoltaic Systems
摘要： This article presents an energy harvesting approach for a concentrated photovoltaic (CPV) system based on cell-block-level integrated CMOS converters. The CPV system, built upon the laterally arrayed multibandgap (LAMB) cell structure, is a potentially higher-efficiency and lower-cost alternative to traditional tandem-based systems. The individual cells within a sub-module block are connected for approximate voltage matching, and a multi-input single-output (MISO) buck converter harvests and combines the energy while performing maximum power point tracking (MPPT) locally for each cell type. A miniaturized MISO dc–dc prototype converter operating at 10 MHz is developed in a 130 nm CMOS process. For 45–160-mW power levels, the prototype converter achieves >92% nominal and >95% peak efficiency in a small (4.8 mm2) form factor designed to fit within available space in a LAMB PV cell block. The results demonstrate the potential of the LAMB CPV architecture for enhanced solar energy capture.
关键词： concentrated photovoltaic (CPV) systems,CMOS dc–dc power converters,energy harvesting,multi-input single-output (MISO) dc–dc converter,maximum power point tracking (MPPT)
更新于2025-09-23 15:21:01
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[Energy, Environment, and Sustainability] Sensors for Automotive and Aerospace Applications || Energy Harvesting Techniques for Powering Wireless Sensor Networks in Aircraft Applications: A Review
摘要： In the recent years, wireless sensors (WS) have utilized for various structural applications such as structural health monitoring and ?ight tests. The conventional battery system to power these sensors is inef?cient due to several limitations including heavyweight, large size, less power output, short cycle life, and requirement of their replacements. Therefore energy harvesting systems are gaining much research attention to build the self-powered WS. The energy harvesting unit can directly extract the energy from the local environment such as pressure, vibration, wind, thermal gradients and the solar source. The reported energy harvesting methods are piezoelectric, triboelectric, thermoelectric, electro-magnetic, and magnetostrictive. This review focuses on the different energy harvesting techniques and challenges of their integration with the WS for the aircraft applications.
关键词： Energy harvesting,Structural health monitoring,Wireless sensors,Aircraft structures
更新于2025-09-23 15:21:01
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Physical Layer Security For Dual-Hop VLC/RF Communication Systems
摘要： In this letter, we investigate the physical layer security of a mixed visible light communication (VLC)/radio frequency (RF) system. More specifically, the relay can extract the direct current (DC) component and collect energy from the optical signal in the VLC link, and then use this collected energy to retransmit data though the RF link. With this setup, the exact performance expressions for secure outage probability and average secrecy capacity are derived in closed-form. We also provide asymptotic results to investigate the effect of different system parameters on the system performance. Finally, we present numerical results to illustrate our analytical result.
关键词： Energy harvesting,physical layer security,visible light communication,secure outage probability
更新于2025-09-23 15:21:01
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One Octave Bandwidth Rectifier With a Frequency Selective Diode Array
摘要： In this paper, a high-efficiency rectifier with one octave bandwidth is proposed by proposing a diode array with a frequency selective topology. With the frequency selective topology, the low-and high-band rectifiers are combined together without extra matching circuit at the input leading to a high-efficiency broadband design. For validation, a prototype rectifier was fabricated and characterized. The measured results show that the RF-dc power conversion efficiency (PCE) maintains above 70% from 1.75 to 3.55 GHz at an input power of 10 dBm. The measured PCE remains more than 50% within 1.4–3.7 GHz and the |S11| is lower than ?10 dB from 1.7 to 3.6 GHz.
关键词： energy harvesting (EH),frequency selection,high efficiency,Broadband RF rectifier,impedance matching,wireless power transfer (WPT)
更新于2025-09-23 15:21:01
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Simultaneous Spectrum Sensing and Energy Harvesting
摘要： This paper proposes a new simultaneous spectrum sensing (SS) and energy harvesting (EH) scheme, called integrated SS-EH, where all of the incoming radio frequency (RF) power is used for EH. Then, SS is performed based on a fraction of the harvested power. The proposed approach does not require a separate energy detector which needs a power-hungry radio front end. Therefore, the energy consumption and hardware complexity for SS can be reduced significantly. Furthermore, it can increase the harvested energy over the conventional separated SS-EH scheme, where SS and EH are performed separately and thus only a fraction of incoming RF power can be used for EH. The combined benefit of reduced energy consumption for SS and increased energy harvest allows more energy to be available for communication, which results in an increase of the throughput. The probability of false alarm and missed detection, the average harvested energy, and the average throughput are analyzed in Rayleigh fading channel and compared with the conventional separated SS-EH scheme. Mixed SS and EH scheme is proposed in cooperative SS and EH environment where each sensor operates in either the integrated SS-EH or the separated SS-EH mode to improve the sensing accuracy at the fusion center.
关键词： mixed cooperative spectrum sensing,RF-powered cognitive radio networks,Integrated spectrum sensing and energy harvesting
更新于2025-09-23 15:21:01
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A Survey of NFC Sensors Based on Energy Harvesting for IoT Applications
摘要： In this article, an overview of recent advances in the field of battery-less near-field communication (NFC) sensors is provided, along with a brief comparison of other short-range radio-frequency identification (RFID) technologies. After reviewing power transfer using NFC, recommendations are made for the practical design of NFC-based tags and NFC readers. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. Finally, a survey of the state of the art in NFC-based sensors is presented, which demonstrates that a wide range of sensors (both chemical and physical) can be used with this technology. Particular interest arose in wearable sensors and cold-chain traceability applications. The availability of low-cost devices and the incorporation of NFC readers into most current mobile phones make NFC technology key to the development of green Internet of Things (IoT) applications.
关键词： green electronics,NFC,energy harvesting,IoT
更新于2025-09-23 15:21:01