Radio reception relies on the medium which determines the propagation characteristics of the electromagnetic fields carrying the information. The permittivity varies greatly depending on the medium, but it remains nearly constant, except when magnetic materials are used. For this reason, magnetic fields, typically affected by permeability, can be utilized in microwave challenging environments. In this paper, a new approach based on the giant magnetoimpedance (GMI) effect is presented. The proposed GMI-based receiver has an effective double-superheterodyne topology, where “effective” means that the receiver actually has a single mixer but appears to have added a virtual mixer due to the GMI effect. The magnetic field-to-voltage conversion ratio (MVCR), the spurious free dynamic range (SFDR) and the receiver sensitivity are characterized, and from these results the optimal operating conditions of the fabricated receiver are obtained. Additionally, wireless digital communication using on-off keying (OOK) is demonstrated and transmitted and received waveforms are compared, with the final demodulation result of the receiver showing that the transmitted digital data are precisely extracted.

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Giant Magnetoimpedance Receiver With a Double-Superheterodyne Topology for Magnetic Communication

The main objective of the study is the experimental determination of switching characteristics of the vacuum interrupter phases, which is a crucial part of the high voltage vacuum circuit breaker. Experimental imitative testing is a better method of testing high voltage vacuum circuit breakers. New imitative testing scheme (Vale-Dobker) is designed to test each phase of the vacuum circuit breakers (VCB) in different ranges of high voltage to achieve maximum performance. Experimental study reveals that the Vale-Dobker scheme is better than others. A new imitative method for testing the vacuum circuit breaker has been presented. To determine its switching characteristics, the imitative test circuit by Vale-Dobker was applied, forming on the test object a fault current ranging from 1 to 10 kA and a transient recovery voltage across the contacts of the vacuum chamber up to 20 kV. The results confirm that the imitative controlled switching testing can suppress the current and overvoltage, thus fundamentally improving the efficiency and system safety.

Investigation of Experimental Imitative Testing of Vacuum Circuit Breaker

In this paper, first time Silicon carbide (SiC) nanoparticles have been laser fabricated, characterized and introduced into the flexible Kapton substrate for thermal heater application. The primary attention is devoted to emerging thermal sensor applications for the nuclear industry, bringing a boon or a security purpose. The fabricated structures were characterized through the scan electron microscopy (SEM), ultra violet microscope (UV) used for absorbance and electrochemical oxidation and reduction in terms of stability of sillion carbide nanoparticles. Combining the excellent electrical properties of Silicon carbide and high temperature tolerance of polyimide, we demonstrated for the first time a flexible SiC sensor. A quick and simple approach is used to fast fabricate the thermal heater prototype. This facile method for synthesizing SiC nanoparticles provides a new idea for high-value thermal heater application for nuclear sensor. 

Design, Fabrication and Characterization of flexible laser reduced Silicon Carbide nanoparticle thermal heater sensor

In this letter, wireless charging chests suitable for smart garments are analyzed and optimized. The coil structure is optimized to generate a uniform magnetic field in a variety of drawer sizes. With the hybrid Helmholtz–solenoid coil structure, the variation of coupling factor is reduced from 78.2% to 26.4% as compared with solenoidal coil. Two design approaches for multidrawer chest are examined. In the first approach, the coils are optimized for individual drawers. In the second approach, the coils are optimized by considering the entire drawer chest. The measurement results show that the second approach further reduces the variation of charging current of receiver coils placed at different locations.

Design and Optimization of Wireless Charging Drawer Coil for Smart Garments

This paper presents the topology of a novel approach to magnetic communication using a differential magnetic induction (MI)-based receiver and a differential MI receiving sensor. In this paper, a differential MI sensor based on two ferromagnetic cores is proposed as a receiving sensor, unlike the air coil-type MI sensor in the conventional search coil sensor concept. This differential MI sensor has the advantages of ultra-high sensitivity characteristics of the pT/ $\surd $ Hz level, which can detect weak magnetic fields in magnetic communication; moreover, the sensor is smaller than a conventional air coil MI sensor. The proposed differential MI sensor contributes to improving sensor performance by increasing its signal-to-noise ratio. The design and fabrication of the proposed MI sensor were based on a printed circuit board (PCB). The pickup coil of the PCB-based MI sensor directly wound the pickup coil onto a ferromagnetic core composed of Ni-Zn ferrite material. To analyze the key factors that affected the performance of the receiver, the magnetic field-to-voltage conversion ratio (MVCR) and equivalent magnetic spectral density measurements of the proposed PCB-based MI sensor were performed. Wireless digital communication using quadrature phase shift keying (QPSK), which is less sensitive to noise and has a high data rate, was used to evaluate the proposed MI-based receiver. The transmitted and received waveforms were compared to confirm that the transmitted digital data were accurately received as a result of the final demodulation of the receiver. Additionally, several performance metrics, such as constellation and error vector magnitude, were measured. The results of the comprehensive analysis confirmed the applicability of the proposed differential MI-based receiver to a magnetic field.

Experimental Assessment of a Magnetic Induction-Based Receiver for Magnetic Communication

In this research, a Helmholtz coil is designed and developed to create a uniform magnetic field. This coil is mainly designed to measure the different parameters of the coils. The coil is designed in such a way that it reduces electromagnetic compatibility test time which is a representative of the actual electromagnetic environment of energy system. These special type of capacitor banks have an important role in improving the power losses and to create uniform magnetic field in the coil. Experimental value of the uniform magnetic field strength in various directions are presented. Specifically, this research presents new experimental analysis of designing a Helmholtz coil of an axial 4-coil system based on Helmholtz coils.

Francis N. S

Papers

Design and Development of Helmholtz Coils for Magnetic Field