Wireless power transfer (WPT) can be classified into magnetic induction, magnetic resonance, and RF radiation types, of which the magnetic resonance WPT system is especially attracting attention due to its high potential for development. The magnetic resonance system using a specific resonance frequency is applicable to small mobile devices and in-body wireless charging modules because it enables the implementation of single-input multiple-output (SIMO), where the transmitter transmits power to multiple receivers, and the miniaturization of receiving coil. The most important consideration of the magnetic resonance WPT is the optimization of the power transfer distance and efficiency, which requires a precise design and the analysis of the transmission coil. Ferrite-embedded LTCC inductors are more advantageous for WPT applications than coil inductors because of their low cost, batch manufacturing and durability. A coil with the substate size of 10.0×12.0×0.7mm3 was manufactured using the ferrite-embedded LTCC technology to miniaturize the receiver coil. The sum of power transferred from transmitter sized of 80×60mm2 to two receivers is approximately 32%, which indicates a high potential for use in small terminals or in-body modules.

This paper analyzes and compares two methods to estimate electromagnetically coupled noises introduced to an antenna due to the nearby circuits at a circuit design stage. One of them is to estimate the power spectrum, and the other one is to estimate the active S11 parameter at the victim antenna, respectively, and both of them use simulated standard S-parameters for the electromagnetic coupling in the circuit. They also need the assumed or measured excitation of noise sources. To confirm the validness of the two methods, an evaluation board consisting of an antenna and noise sources were designed and fabricated in which voltage controlled oscillator (VCO) chips are placed as noise sources. The generated electromagnetic noises are transferred to an antenna via loop-shaped transmission lines, degrading the performance of the antenna. In this paper, detailed analysis procedures are described using the evaluation board, and it is shown that the two methods are equivalent to each other in terms of the induced voltages in the antenna. Finally, a procedure to estimate antenna performance degradation at the design stage is summarized.

When the track density of two-dimensional magnetic recording (TDMR) systems is increased, intertrack interference (ITI) inevitably grows, resulting in the extreme degradation of an overall system performance. In this work, we present coding, writing, and reading techniques which allow TDMR systems with multi-readers to overcome severe ITI. A rate-5/6 two-dimensional (2D) modulation code is adopted to protect middle-track data from ITI based on cross-track data dependence. Since the rate-5/6 2D modulation code greatly improves the reliability of the middle-track, there is a bit-error rate gap between middle-track and sidetracks. Therefore, we propose the different track width writing technique to optimize the reliability of all three data tracks. In addition, we also evaluate the TDMR system performance using an user areal density capability (UADC) as a main key parameter. Here, an areal density capability (ADC) can be measured by finding the bit-error rate of the system with sweeping track and linear densities. The UADC is then obtained by removing redundancy from the ADC. Simulation results show that a system with our proposed techniques gains the UADC of about 4.66% over the conventional TDMR systems.

When AgSnO2 contacts were operated to break an inductive DC load current of 14V-12A, 20V-7A or 20V-17A at a contact opening speed of 10mm/sec or slower, application of an external magnetic field resulted in reductions in break arc durations even without magnetic blowing. Simple estimation of Lorentz force to be applied onto arc column revealed that a certain minimum magnitude of Lorentz force seems to be required for initiating arc blowing. Certain relationships between the Lorentz force magnitude and the timing of metallic-to-gaseous phase transition were also found to exist.

With the advantages of higher blocking voltage, higher operation temperature, fast-switching characteristics, and lower switching losses, the silicon carbide (SiC) MOSFET has attracted more attentions and become an available replacement of traditional silicon (Si) power semiconductor in applications. Despite of all the merits above, electromagnetic interference (EMI) issues will be induced consequently by the ultra-fast switching transitions of the SiC MOSFET. To quickly and precisely assess the switching behaviors of the SiC MOSFET for EMI investigation, an analytical model is proposed. This model has comprehensively considered most of the key factors, including parasitic inductances, non-linearity of the junction capacitors, negative feedback effect of Ls and Cgd shared by the power and the gate stage loops, non-linearity of the trans-conductance, and skin effect during voltage and current ringing stages, which will considerably affect the switching performance of the SiC MOSFET. Additionally, a finite-state machine (FSM) is especially utilized so as to analytically and intuitively describe the switching behaviors of the SiC MOSFET via Stateflow. Based on double pulse test (DPT), the effectiveness and correctness of the proposed model are validated through the comparison between the calculated and the measured waveforms during switching transitions. Besides, the model can appropriately depict the spectrum of the drain-source voltage of the MOSFET and is suitable for EMI investigation in applying of SiC devices.

Electromagnetic relays were developed in the first half of 19th century. At the beginning, they have been mainly used for telecommunication systems, afterwards, their uses were expanded, they have been applied to various systems such as industry products, traffic control equipment, household appliances and so on. During this time, international standardization on them became active, Japan took part in the auxiliary relay committee in the International Electrotechnical Commission (IEC). Recently, Japan is playing an important role in the committee activities. In this paper, transition and the present circumstance on technical trends of the electromagnetic relays and their activities on international standardization are described, talking about some future prospects.

In this paper, we propose a novel framework for structural magnetic resonance image (sMRI) classification of Alzheimer's disease (AD) with data combination, outlier removal, and entropy-based data selection using AlexNet. In order to overcome problems of conventional classical machine learning methods, the AlexNet classifier, with a deep learning architecture, was employed for training and classification. A data permutation scheme including slice integration, outlier removal, and entropy-based sMRI slice selection is proposed to utilize the benefits of AlexNet. Experimental results show that the proposed framework can effectively utilize the AlexNet with the proposed data permutation scheme by significantly improving overall classification accuracies for AD classification. The proposed method achieves 95.35% and 98.74% classification accuracies on the OASIS and ADNI datasets, respectively, for the binary classification of AD and Normal Control (NC), and also achieves 98.06% accuracy for the ternary classification of AD, NC, and Mild Cognitive Impairment (MCI) on the ADNI dataset. The proposed method can attain significantly improved accuracy of up to 18.15%, compared to previously developed methods.

In this paper, we have investigated the etching selectivity of HfN encapsulating layer for high quality PtHf-alloy silicide (PtHfSi) formation with low contact resistivity on Si(100). The HfN(10 nm)/PtHf(20 nm)/p-Si(100) stacked layer was in-situ deposited by RF-magnetron sputtering at room temperature. Then, silicidation was carried out at 500°C/20 min in N2/4.9%H2 ambient. Next, the HfN encapsulating layer was etched for 1-10 min by buffered-HF (BHF) followed by the unreacted PtHf metal etching. We have found that the etching duration of the 10-nm-thick HfN encapsulating layer should be shorter than 6 min to maintain the PtHfSi crystallinity. This is probably because the PtHf-alloy silicide was gradually etched by BHF especially for the Hf atoms after the HfN was completely removed. The optimized etching process realized the ultra-low contact resistivity of PtHfSi to p+/n-Si(100) and n+/p-Si(100) such as 9.4×10-9Ωcm2 and 4.8×10-9Ωcm2, respectively, utilizing the dopant segregation process. The control of etching duration of HfN encapsulating layer is important to realize the high quality PtHfSi formation with low contact resistivity.

This paper presents a rigorous analysis of the electromagnetic scattering and transmission of misaligned dual metallic grating screens. The Fourier transform and the mode-matching technique are employed to obtain an analytical solution. Numerical results show that misaligned dual metal grating screens exhibit asymmetric scattering and transmission properties with respect to the scattering and transmission angles. Parametric studies are conducted in terms of the lateral displacement and vertical distance between the dual metallic grating screens. For validation, the proposed method is compared with a numerical simulation and good agreement has been achieved.

Break arcs are generated in a 48VDC resistive circuit. Circuit current I0 when electrical contacts are closed is changed from 50A to 300A. The break arcs are observed by a high-speed camera with appropriate settings of exposure from horizontal direction. Length of the break arcs L is measured from images of the break arcs. Time evolutions of the length L and gap voltage Vg are investigated. The following results are obtained. By appropriate settings of the high-speed camera, the time evolution of the length L is obtained from just after ignition to before arc extinction. Tendency of increase of the length L is similar to that of increase of the voltage Vg for each current I0.

A 1-Transistor 4-Magnetic Tunnel Junction (1T-4MTJ) memory cell has been proposed for field type of Magnetic Random Access Memory (MRAM). Proposed 1T-4MTJ memory cell array is achieved 44% higher density than that of conventional 1T-1MTJ thanks to the common access transistor structure in a 4-bit memory cell. A self-reference sensing scheme which can read out with write-back in four clock cycles has been also proposed. Furthermore, we add to estimate with considering sense amplifier variation and show 1T-4MTJ cell configuration is the best solution in IoT applications. A 1-Mbit MRAM test chip is designed and fabricated successfully using 130-nm CMOS process. By applying 1T-4MTJ high density cell and partially embedded wordline driver peripheral into the cell array, the 1-Mbit macro size is 4.04 mm2 which is 35.7% smaller than the conventional one. Measured data shows that the read access is 55 ns at 1.5 V typical supply voltage and 25C. Combining with conventional high-speed 1T-1MTJ caches and proposed high-density 1T-4MTJ user memories is an effective on-chip hierarchical non-volatile memory solution, being implemented for low-power MCUs and SoCs of IoT applications.

This paper presents a method combining array signal processing and adaptive noise cancellation to suppress unwanted ambient interferences in in situ measurement of radiated emissions of equipment. First, the signals received by the antenna array are processed to form a main data channel and an auxiliary data channel. The main channel contains the radiated emissions of the equipment under test and the attenuated ambient interferences. The auxiliary channel only contains the attenuated ambient interferences. Then, the adaptive noise cancellation technique is used to suppress the ambient interferences based on the correlation of the interferences in the main and auxiliary channels. The proposed method overcomes the problem that the ambient interferences in the two channels of the virtual chamber method are not correlated, and realizes the suppression of multi-source ambient noises in the use of fewer array elements. The results of simulation and experiment show that the proposed method can effectively extract radiated emissions of the equipment under test in complex electromagnetic environment. Finally, discussions on the effect of the beam width of the main channel and the generalization of the proposed method to three dimensionally distributed signals are addressed.

Coil-shaped structures are proposed to enhance sensitivity and spatial resolution for EMI near-field probe. This design yields a high sensitivity and a good spatial resolution to find the EMI source in near-field region. Both characteristics are crucial to diagnosis of emissions from electrical and electronic devices. The new design yields a superior sensitivity, which is in general 15 dB greater than conventional probes. This new probe helps practitioners to quickly and correctly locate noise emission source areas on printed circuit boards and devices. Two prototypes of different sizes were fabricated. The larger one provides a high sensitivity while the smaller one can pinpoint emission source locations. The new probe design also has an orientation invariance feature. Its noise response levels are similar for all probe directions. This characteristic can help reduced the probability at miss-detection since sensitivity is largely invariant to its orientation. Extensive measurements were performed to verify the operation mechanism and to assess probe characteristics. It suits well to the electromagnetic interference problem diagnosis.

This paper proposes fabrication process of a pyramidal electromagnetic (EM) absorber made by natural rubber. The advantage of this research is to generate value-added latex from Thai rubber and to reduce number of chemical absorber by using natural rubber based absorber. The proposed absorber in the research is mainly made from latex with carbon black filler. The proposed absorber is in the form of rubber foam which provides suitable characteristics to serve as an EM absorber. The results of this research are chemical formulas for fabrication of pyramidal rubber foam with carbon black filler. The fabrication cost is very low when compared to an available commercial absorber. The electrical properties of the proposed EM absorber are measured. Also the reflectivity is measured and compared well with a commercial EM absorber.

With the rising importance of information security, the necessity of implementing better security measures in the physical layer as well as the upper layers is becoming increasing apparent. Given the development of more accurate and less expensive measurement devices, high-performance computers, and larger storage devices, the threat of advanced attacks at the physical level has expanded from the military and governmental spheres to commercial products. In this paper, we review the issue of information security degradation through electromagnetic (EM)-based compromising of security measures in the physical layer (i.e., EM information security). Owing to the invisibility of EM radiation, such attacks can be serious threats. We first introduce the mechanism of information leakage through EM radiation and interference and then present possible countermeasures. Finally, we explain the latest research and standardization trends related to EM information security.

This paper presents various Iterative Progressive Numerical Methods (IPNMs) for the computation of electromagnetic (EM) wave scattering from many objects. We previously modified the original IPNM from the standpoint of the classical and the IDR-based linear iterative solvers. We demonstrate the performance of the IDR(s)-based IPNMs through some numerical examples of EM wave scattering from regularly placed 27 perfectly electric conducting spheres.

Forward converter is most suitable for low voltage and high current applications such as LEDs, battery chargers, EHV etc. The active clamp transformer reset technique offers many advantages over conventional single-ended reset techniques, including lower voltage stress on the main switch, the ability to switch at zero voltage and duty cycle operation above 50 percent. Several papers have compared the functional merits of the active clamp over the more extensively used RCD clamp, third winding and resonant reset techniques. This paper discusses about a center clamp technique with one common core reset circuit making it suitable for wide input voltage applications with extended duty cycle.

In this study, transverse magnetic electromagnetic plane wave scatterings by rectangular cylinders have been analyzed by a high frequency asymptotic method. Scattering field can be generated by the equivalent electric and magnetic currents which are obtained approximately from the geometrical optics (GO) fields. Our formulation is found to be exactly the same with the physical optics (PO) for the conducting cylinders, and it can also be applicable for dielectric cylinders. Numerical calculations are made to compare the results with those by other methods, such as the geometrical theory of diffraction (GTD) and HFSS simulation. A good agreement has been observed to confirm the validity of our method.

This paper describes the equivalent-circuit model of a metamaterial composed of conducting spheres and wires. This model involves electromagnetic coupling between the conductors, with retardation. The lumped-parameter equivalent circuit, which imports retardation to the electromagnetic coupling, is developed in this paper from Maxwell's equation. Using the equivalent-circuit model, we clarify the relationship between the retardation and radiation loss; we theoretically demonstrate that the electromagnetic retardation in the near-field represents the radiation loss of the meta-atom in the far-field. Furthermore, this paper focuses on the retarded electromagnetic coupling between two meta-atoms; we estimate the changes in the resonant frequencies and the losses due to the distance between the two coupled meta-atoms. It is established that the dependence characteristics are significantly affected by electromagnetic retardation.

Reverberation chambers (RCs) are used widely in the electromagnetic measurement area. An RC is designed to have a long reverberation time, generate numerous modes, and provide good field uniformity within the chamber. The purpose of this paper is to describe the design process and measurement of the KRISS Reverberation Chamber (KRC). KRC models with 4.5m × 3.4m × 2.8m dimensions are simulated by 3D numerical simulation software. The field uniformity and correlation coefficient are then analyzed at 200MHz to obtain the optimized model. The simulation results show good performance in terms of field uniformity and are confirmed by measurement from 200MHz to 1GHz. The lowest usable frequency (LUF) of KRC was confirmed by field uniformity to be 200MHz. However, the stirrer correlation coefficient results show good performance above 300MHz.