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NUMERICAL ESTIMATION OF THE COMPLEX REFRACTIVE INDEXES BY THE ALTITUDE DEPENDING ON WAVE FREQUENCY IN THE IONIZED REGION OF THE EARTH ATMOSPHERE FOR MICROWAVES INFORMATION AND POWER TRANSMISSIONS
摘要： The phase and group refractive indexes of microwaves in the ionosphere region of the earth atmosphere are very important for both the researching theoretical problems and practical problems in wireless information transmission (WIT) and wireless power transmission (WPT). So far, there have been many attempts devoted to discussing and determining characterizations of earth atmosphere’s ionosphere region including the refractive indexes of microwaves concerning their velocities in ionized region, unfortunately due to the complicated features of the ionosphere region leading to research task facing many challenges. Up to recent, there is still a lack of systematic numerical data of complex refractive index by altitude depending on high frequencies of the electromagnetic waves in the ionosphere region. This paper outlines some theoretical analyses and discussions of some theoretical aspects of the complex refractive index in atmosphere’s ionized region more in detail. Based on conductivities data and the complex relative permittivity by altitude determined previously, the numerically estimated data of complex refractive indexes by the altitude from 100 km up to 1000 km at the di?erent frequencies are also shown and discussed.
关键词： wireless information transmission,refractive index,microwaves,ionosphere,wireless power transmission
更新于2025-09-23 15:21:21
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An Ultralight Concentrator Photovoltaic System for Space Solar Power Harvesting
摘要： We present a detailed design treatment for a concentrating photovoltaic mini module subsystem with a specific power of up to 4.1 kW/kg for integration into a space solar power system. Concentrating designs are required to achieve specific power over 1 kW/kg with current high-efficiency III-V multijunction solar cells. The 15 sun, linear concentration concept detailed here reduces the system mass by replacing cell and radiation shield area with ultralight carbon fiber reinforced polymer (CFRP) optics. Reducing the cell size to 1mm width as well as careful optimization of cell architecture and CFRP material and thickness are critical for maintaining cell temperatures under 100 C despite the concentration. We also describe ultralight multilayer optical coatings to increase the thermal emissivity of the concentrator surfaces and enhance radiative transfer for cell cooling, which is a critical technological component of the total system design.
关键词： wireless power transmission,solar cells,aerospace materials,Space-based solar power,concentrating photovoltaics
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE/MTT-S International Microwave Symposium - IMS 2019 - Boston, MA, USA (2019.6.2-2019.6.7)] 2019 IEEE MTT-S International Microwave Symposium (IMS) - Triple-Band Near-Field Wireless Power Transfer System Using Coupled Defected Ground Structure Band Stop Filters
摘要： For the first time, a triple-band near-field wireless power transfer (WPT) system is presented using coupled triple-band defected ground structure (DGS) bandstop filters (BSF). A triple-band DGS-BSF is possible through creating a frequency dependent effective lower inductance at higher frequencies. When we couple two triple-band DGS-BSFs in a back-to-back configuration, a triple-band DGS-WPT system is created. We verify the proposed DGS-WPT system through good agreements between electromagnetic simulations and measurements. The measured WPT efficiencies are 68%, 60%, and 65% at 100.8 MHz, 140.7 MHz, and 182.2 MHz, respectively at a WPT separation distance of 30 mm. Each of the WPT transmitter and receiver has a size of 50 × 50 mm2.
关键词： defected ground structures,wireless power transmission,mutual coupling,multi-band
更新于2025-09-12 10:27:22
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Temperature impact on parameters of In <sub/>0.3</sub> Ga <sub/>0.7</sub> As PV cell under laser irradiation condition
摘要： The parameters of In0.3Ga0.7As PV cell applied in laser wireless power transmission (LWPT) system dependence on temperature was investigated at a temperature range of 5-90○C under 100mW/cm2 laser intensity with 1070nm wavelength. The pollination algorithm method was used to extract parameters, viz., photocurrent, series and shunt resistance, reverse saturation current, and ideality factor from the I-V curves at each temperature point. The results show that the short circuit current decrease exponentially with temperature increasing, which is obviously different from the condition with solar irradiation. As temperature increases, the conversion efficiency and the open circuit voltage decreases linearly at the rate of 0.095%/○C and 1.89mV/○C, respectively. In addition, the dependence of series and shunt resistance, ideality factor, and fill factor on temperature was also analyzed. This research gives us a new understanding of PV cells under laser irradiation condition, also provides a direction for manufacturing the cells used in LWPT system.
关键词： laser wireless power transmission,conversion efficiency,In0.3Ga0.7As PV cell,pollination algorithm,temperature dependence
更新于2025-09-12 10:27:22
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200 mW-class LED-based optical wireless power transmission for compact IoT
摘要： For Internet of Things terminals such as many types of sensors, tags or beacons, wiring and using batteries are less effective power supplying methods due to excessive installation and maintenance costs. Wireless power transmission is a promising candidate, particularly optical wireless power transmission (OWPT), with its attractive advantages of long transmission distance, good directionality and small size. However, previous researches of OWPT are almost all focused on laser as a light source, which is difficult to use in the usual spaces due to possible safety reasons at the current stage. In this research, an LED-based OWPT system that realized large electricity power supply was designed and demonstrated. 223.9 mW of output power from 100 cm distance was achieved with a 1.7 × 1.7 cm2 size GaAs solar cell as a receiver. Around 77% of optical system efficiency was confirmed at a 2.1 × 2.3 cm2 irradiation size. The total power feeding efficiency was 6.3%.
关键词： optical wireless power transmission,IoT,LED,GaAs solar cell,wireless power transmission
更新于2025-09-11 14:15:04
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[Lecture Notes in Electrical Engineering] Engineering Vibration, Communication and Information Processing Volume 478 (ICoEVCI 2018, India) || Design of an Energy Harvesting System for Wireless Power Transmission Using Microstrip Antenna
摘要： Power supply drives technological devices. As the wired world looks long antiquated, it is imperative transition towards wireless power transmission (WPT). WPT has been lately enticing in a varying range of applications in numerous ?elds and has also become a very alluring area of research activity because of the potential it has in providing solutions to our daily requirement, so the need arises to delve into it to explore new, innovative and ef?cient means of energy transmission. WPT will be indispensable in the imminent future, as this technology assists in the transmission of electrical energy to any device from the power source using air as the transmission medium without the use of any conductors. In this paper, an energy harvesting device is proposed to convert ambient electromagnetic waves, predominantly from the 2.4 GHz ISM radio frequency (RF) channel into direct current (DC) electricity. A microstrip antenna is designed along with a booster circuit to help charge devices wirelessly. This novel technology could be used for charging phone batteries on-the-go, thereby eliminating the hassles of wired connections.
关键词： Rectenna,Wireless power transmission,Energy harvesting,Wireless charging,Microstrip patch antenna
更新于2025-09-10 09:29:36
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[IEEE 2018 37th Chinese Control Conference (CCC) - Wuhan (2018.7.25-2018.7.27)] 2018 37th Chinese Control Conference (CCC) - Maximum Power Tracking of Wireless Power Transmission Systems Based on Critical Coupling Point Tracking
摘要： Power transmission is one of the key issues in wireless power transmission (WPT) systems and the maximum power transmission problem is considered in this paper. A load power model for the magnetic resonant coupling WPT system with string-to-string structure is carried out at first. And then, using the power normalization method, the theoretical performance is analyzed and a special working point called critical coupling point (CCP) is found. At this point, the system can transfer the possible maximum power. Thus, maximum power tracking (MPT) problem can be transformed into the critical coupling point tracking (CCPT) problem. Further, relationship between CCP and load resistance is analyzed. To achieve the maximum transmission power under any load, a DC-DC impedance conversion circuit is added at the receiving side so that the maximum power can be tracked by adjusting the equivalent load resistance dynamically. Simulation results show the effectiveness of the proposed method.
关键词： maximum power tracking,critical coupling point,wireless power transmission
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Flexible 2.45 GHz Rectenna Using Electrically Small Loop Antenna
摘要： We present the concept and design of a compact flexible electromagnetic energy-harvesting system using electrically small loop antenna. In order to make the integration of the system with other devices simpler, it is designed as an integrated system in such a way that the collector element and the rectifier circuit are mounted on the same side of the substrate. The rectenna is designed and fabricated on flexible substrate, and its performance is verified through measurement for both flat and curved configurations. The DC output power and the efficiency are investigated with respect to power density and frequency. It is observed through measurements that the proposed system can achieve 72% conversion efficiency for low input power level, -11 dBm (corresponding power density 0.2 W/m2), while at the same time occupying a smaller footprint area compared to the existing work.
关键词： energy harvesting,flexible rectenna,wireless power transmission
更新于2025-09-04 15:30:14