Misalignments between the transmitting and receiving coils of a wireless power system can significantly reduce power transfer efficiency (PTE). In this paper, we propose a novel magnetically coupled resonant wireless power transfer (MCR-WPT) system with good misalignment tolerance for wireless charging applications. Specifically, we employ three interconnected planar coils to form a transmitter that produce multiple paths of magnetic flux linkages and power to the receiver even in angular and lateral misalignment positions. Unlike other methods, no additional control circuits are needed so that the circuit can be easily realized and implemented. A prototype is simulated, fabricated, and tested. It has a wide angular misalignment range of 165° for the power transfer efficiency of 20% or higher, which is 30% higher than 126° of the conventional system. It also has a wide lateral misalignment range of 180 mm for the power transfer efficiency of 20% or higher, which is 73% higher than 104 mm of the conventional system. Thus, the proposed system presents a good and simple wireless power delivering system for practical applications, in particular in the situations where angular and lateral misalignments occur in various degrees without prior acknowledge.

This brief demonstrated a body-wide RF energy harvester based on textile spoof surface plasmon (SSP) antenna array for wearable wireless power transmission. This harvester includes four patch antennas and SSP waveguides to form an SSP antenna array integrated with clothing to harvest the incident RF energy. Then, a loop and rectifier are integrated and fabricated in the same plane to extract, combine, rectify and output DC power from the multi-path harvested energy in a contactless way and without a complex matching network. They are fabricated with a simple structure, entirely off-the-shelf flexible and textile materials, and a proven fabrication technique. Finally, it is worn on the body to output DC power of $108.89~\mu \text{W}$ when illuminated with a power density of $7.96~\mu \text{W}$ /cm2 at 2.4-2.45 GHz Industrial Scientific Medical (ISM) band. This design could be applied to power the potential wearable sensors wirelessly.

A novel L-band wideband coaxial mode-transducing antenna, which converts the coaxial TEM mode into circular TM01 mode, is realized and tested in this article. The mode-transducing antenna is composed of a coaxial wideband multiple-reflection mode converter with the three groups of supporting rods and a compact coaxial conical horn with a dielectric lens. First, the schematic and operating principle of the mode-transducing antenna are analyzed theoretically. Then, the structure design and optimization with simulated results are performed for demonstration. Finally, a prototype of the mode-transducing antenna is fabricated, measured, and verified in terms of reflection characteristics, radiation patterns, and far-field waveforms. The measured results reveal that the mode-transducing antenna achieves the bandwidth wider than 31% with the transmission efficiency higher than 98.2%. The high-power test with the magnetically insulated transmission-line oscillator (MILO) show that the power handing capacity of the mode-transducing antenna is greater than 4.0 gigawatts (GW). The measured results are in good agreement with the simulated results. Therefore, the mode-transducing antenna has a good application prospect in the field of high-power microwave (HPM).

Blade icing caused by low-temperature environments results in the degradation of wind turbine power performance. As there is no obvious influence on the performance of wind turbines in the early stage of blade icing, it is difficult to detect the early icing state, so there will be inaccurate labels in the process of data collection. To address these challenges, this paper proposes a novel semi-supervised blade icing detection method based on a tri-training algorithm. In the proposed method, extreme gradient boosting tree (XGBoost) is used as the base classifier. A tri-training algorithm is used to integrate three base classifiers and the integrated model generates a pseudo-label for unlabeled data. In addition, we introduce Focal Loss as the loss of the base classifier in the proposed model, which solves the problem of class imbalance caused by the fact that the wind turbine is operating under normal conditions in most cases. In order to verify the effectiveness of the proposed blade icing detection method, experiments are implemented on the collected Supervisory Control and Data Acquisition (SCADA) data. The experimental results show that the proposed method effectively improves the ability to identify blade icing. Compared with other methods, it has better classification performance, robustness, and generalization.

The electromagnetic (EM) coupling effects of microstrip antennas have become increasingly prominent in complicated electric systems. In this article, a hybrid method is proposed based on the combination of cavity eigenmode theory and BLT equation. First, the internal electric field generated by the transmission lines inside the resonant cavity is obtained via cavity eigenmode theory. Then, the coupling mechanism between the electric field and microstrip antenna is established through radiation coupling interference. On this basis, the BLT equation and numerical integration method are applied to determine the induced voltage at the target microstrip antenna. Eventually, the proposed approach is validated by a full-wave simulation method and the impact of the microstrip antenna parameters on the coupling interference is discussed. This article provides an analytical method for calculating the coupling of a microstrip antenna. Compared with numerical simulation, this method has certain potential advantages in solving closed electrically large objects. Furthermore, duplicate modeling can be avoided in the same type of scenario.

Strong electromagnetic fields are radiated during the operation of the intense electron-beam accelerator (IEBA), which may lead to the nearby electronic devices out of order. In this paper, the research on the electromagnetic radiation characteristic of the gas main switch of a capacitive IEBA is carried out by the methods of theory analysis and experiment investigation. It is obtained that the gas main switch is the dominating radiation resource. In the absence of electromagnetic shielding for the gas main switch, when the pulse forming line of the IEBA is charged to 700 kV, the radiation field with amplitude of 3280 V/m, dominant frequency of 84 MHz and high frequency 100 MHz is obtained at a distance of 10 meters away from the gas main switch. The experimental results of the radiation field agree with the theoretical calculations. We analyze the achievements of several research groups and find that there is a relationship between the rise time (T) of the transient current of the gas main switch and the dominant frequency (F) of the radiation field, namely, F*T=1. Contrast experiment is carried out with a metal shield cover for the gas main switch. Experimental results show that for the shielded setup the radiation field reduces to 115 V/m, the dominant frequency increases to 86.5 MHz at a distance of 10 away meters from the gas main switch. These conclusions are beneficial for further research on the electromagnetic radiation and protection of the IEBA.