In this paper we mainly focus on the effect of a ferromagnetic material on the critical current of Bi-2223 tape. The magnetic field distributions of tapes with several different layouts of a ferromagnetic material are investigated by calculation and the corresponding critical current is tested experimentally. The analysis indicates that the critical current of the tape can be improved effectively by laying the ferromagnetic material perpendicularly next to the tape edge. Furthermore, various other ferromagnetic parameters are also important for reducing the magnetic field induced by the current flowing through the tape.

When contact failure occurs in a connector in a coaxial HF signal transmission line, an electromagnetic field is radiated around the line. We have measured the electromagnetic field and examined the characteristics of such radiation. The results show that the radiation is related to the contact resistance and the symmetry of the distribution of contact points at the connector. When contact resistance is low, radiation is observed at resonant frequencies related to the length of the transmission line. If a connector has axially asymmetric contact points, its radiation is higher than that when the contact points are symmetric. We show that if contact points in a connector are axially symmetrical with resistance lower than 0.25 Ω, the electromagnetic interference caused by the connector contact failure is as low as the background noise.

VI time responses of a conventional electromagnetic relay during breaking contact operations were measured. In a conventional switching circuit, unstable contact resistance, irregular bouncing, and poor reproducibility were confirmed. Using a transient current switch circuit and two sharpened contact electrodes, bouncing during a breaking operation was suppressed, and unstable contact resistance changes and reproducibility of breaking operation were also improved.

An electrical arc is generated by opening the contacts of a relay when the current is above the minimum arc current in a circuit. A magneto-hydrodynamic (MHD) model was employed to simulate this dynamic arcing process. The distributions of arc parameters such as temperature, electrical field and magnetic flux density generated by opening the contacts in a circuit with a 5 A DC low current were obtained. The behaviors of the arc parameters with increasing gap length between the contacts were also simulated. The MHD model was then combined with structured dynamic layering, which is a dynamic meshing technique of computational fluid dynamics (CFD) to calculate the dynamic arcing process, and the arc parameters generated by opening the contacts in the circuit with a 5 A DC low current with a constant velocity were also obtained. It turned out that the computed time-varying contact voltage and arc duration agreed well with the test results. Thus, the validity of the simulation was demonstrated.

The precision of magnetic field calculation is crucial to predict the arc behavior using magnetohydrodynamic (MHD) model. A integrated calculation method is proposed to couple the calculation of magnetic field and fluid dynamics based on the commercial software ANSYS and FLUENT, which especially benefits to take into account the existence of the ferromagnetic parts. An example concerning air arc is presented using the method.

At high signal frequencies (i.e. in the GHz range), a connector must be considered as part of an electromagnetic transmission line. At these frequencies, the impedance characteristics of the connector stemming from the distributed inductance and capacitance of pins and the associated wiring, must be carefully controlled; insertion losses must be minimized and undesirable coupling between non-neighboring pins giving rise to crosstalk must be avoided to achieve optimal signal transmission. This paper reviews fundamental issues associated with the performance optimization of multi-conductor connector structures for high speed signal transmission. The paper complements an earlier publication that reviewed the major factors affecting electrical contact resistance at high frequencies [1].

Research on the electromagnetic compatibility of functional module composed of two independent electromagnetic relays in a hermetically sealed shell is the technical foundation for integration and miniaturization of electronic equipment in the future. In this paper, 3D finite element method (FEM) was used to analyze the dynamic characteristics of twin-type relay interfered by uniform constant magnetic field and identify the sensitive direction in which the relay was easily interfered. The models of twin-type relay in three working states were founded. Through simulation and analysis, it was found out how the operation time and electromagnetic torque of twin-type relay changed with the outer interfered magnetic field. When the relay was on the point of operation failure, the critical value of magnetic field was calculated through simulation. The simulation results of the dynamic characteristics of twin-type relay agree well with the experimental data. The conclusion in this paper is of great value for research on the electromagnetic compatibility of relay functional module.

Anomalous environmental electromagnetic (EM) radiation waves have been reported as the portents of earthquakes. Our study's goal is predicting earthquakes using EM radiation waves by detecting some anomalies. We have been measuring the Extremely Low Frequency (ELF) range EM radiation waves all over Japan. However, the recorded data contain signals unrelated to earthquakes. These signals, as noise, confound earthquake prediction efforts. In this paper, we propose an efficient method of global signal elimination and enhancement local signals using Independent Component Analysis (ICA). We evaluated the effectiveness of this method.

Impacts of electromagnetic (EM) interference (immunity) on operation of LSI circuits in a QFP-packaged and PCB-mounted environment are studied. EM power injection to a power-supply system leads to malfunction, where the power is translated into voltage bounces through combined on- and off- chip impedances, affecting power supply and ground, as well as signal nodes in a die, seen from on-chip waveform measurements. A lumped power-supply impedance model and the minimum amplitude of voltage bounce induced by EM power for malfunction, both of which can be derived from external measurements to a given packaged LSI, formulate an EM interference model that is helpful in the PCB design toward high immunity. The technique can be generally applied to systems-on-chip applications.

Many studies of on-line comprehension of semantic violations have shown that the human sentence processor rapidly constructs a higher-order semantic interpretation of the sentence. What remains unclear, however, is the amount of time required to detect semantic anomalies while concatenating two words to form a phrase with very rapid stimuli presentation. We aimed to examine the time course of semantic integration in concatenating two words in phrase structure building, using magnetoencephalography (MEG). In the MEG experiment, subjects decided whether two words (a classifier and its corresponding noun), presented each for 66 ms, form a semantically correct noun phrase. Half of the stimuli were matched pairs of classifiers and nouns. The other half were mismatched pairs of classifiers and nouns. In the analysis of MEG data, there were three primary peaks found at approximately 25 ms (M1), 170 ms (M2) and 250 ms (M3) after the presentation of the target words. As a result, only the M3 latencies were significantly affected by the stimulus conditions. Thus, the present results indicate that the semantic integration in concatenating two words starts from approximately 250 ms.

A variable phase shifter using a movable waffle iron metal plate comprised of iron rods a quarter-wavelength in length is proposed. A study of the waffle iron structure was carried out and the design method for creating a structure that would achieve large phase changes, small loss, and good isolation between adjacent phase shifters is discussed. Experiments on 1-port and 2-port phase shifters operating in the 5 GHz band show that they not only have low loss characteristics but also wide phase changes. Furthermore, the application to phased array antennas using the proposed phase shifter and its principle are demonstrated.

To estimate the impact of electromagnetic disturbances on multi-carrier wireless systems, a method for converting an amplitude probability distribution (APD) of disturbance measured at a frequency to be valid for another frequency is presented. The conversion uses two parameters, the receiver noise power of the APD measuring equipment and a scale factor that can be estimated from a measured disturbance spectrum. The method is based on the assumption that the difference in measurement frequency affects only the relative scale of the probability distribution of band-limited disturbance amplitude, and is applicable to disturbances of practically importance such as 1) continuous or pulse-modulated wideband Gaussian noise, 2) disturbance with a much narrower bandwidth than receiver bandwidth B, and 3) repetitive short pulses with similar waveforms with an interval much longer than 1/B. The validity of the proposed method is examined by measurements of actual disturbances.

An exact computable expression is obtained for the electromagnetic field of a three-dimensional partially finite periodic array of lossless or lossy magnetodielectric spheres illuminated by a plane wave propagating parallel to the array axis. The array is finite in the direction of the array axis and is of infinite extent in the directions transverse to the array axis. Illustrative numerical examples are presented.

It is well known that there is relationship between electromagnetic emanation and processing information in IT devices such as personal computers and smart cards. By analyzing such electromagnetic emanation, eavesdropper will be able to get some information, so it becomes a real threat of information security. In this paper, we show how to estimate amount of information that is leaked as electromagnetic emanation. We assume the space between the IT device and the receiver is a communication channel, and we define the amount of information leakage via electromagnetic emanations by its channel capacity. By some experimental results of Tempest, we show example estimations of amount of information leakage. Using the value of channel capacity, we can calculate the amount of information per pixel in the reconstructed image. And we evaluate the effectiveness of Tempest fonts generated by Gaussian method and its threshold of security.

Effects of Fe/Si ratio and growth temperature were investigated in order to realize high quality Fe3Si/Ge structures. It was found that very small χmin values (2-3%) were achieved in a wide temperature range of 60-200 under the stoichiometric condition. From TEM observation, it was rvealed that the Fe3Si/Ge structures with atomically flat interfaces were realized. In addition, thermal stability of the Fe3Si/Ge structures was guaranteed up to 400. These results suggested that growth at a low temperature (<200) under the stoichiometric condition was essential to obtain high quality Fe3Si/Ge structures with sharp interfaces.

This report describes an application of relaxation technique to the alternating direction implicit finite-difference time-domain (ADI-FDTD) method. The ADI-FDTD method is quite stable even when the CFL condition is not satisfied. However, the ADI-FDTD method is computationally more complicate than the conventional FDTD method and this method requires to solving the tri-diagonal matrix equation. Thus, this method may require more computational cost than the standard FDTD method due to the large scale tri-diagonal matrix solution corresponding to a large number of meshes. In this report, relaxation-based solution technique is discussed for the matrix solution and a simple numerical example is shown. As a result, it is confirmed that ADI-FDTD method with the relaxation technique is useful for the acceleration of the electromagnetic field simulation.

A wireless transceiver utilizing inductive coupling has been proposed for communication between chips in system in a package. This transceiver can achieve high-speed communication by using two-dimensional channel arrays. To increase the total bandwidth in the channel arrays, the density of the transceiver should be improved, which means that the inductor size should be scaled down. This paper discusses the scaling theory based on a constant magnetic field rule. By decreasing the chip thickness with the process scaling of 1/α, the inductor size can be scaled to 1/α and the data rate can be increased by α. As a result, the number of aggregated channels can be increased by α2 and the aggregated data bandwidth can be increased by α3. The scaling theory is verified by simulations and experiments in 350, 250, 180, and 90 nm CMOS.

Advances in smart card technology encourages smart card use in more sensitive applications, such as storing important information and securing application. Smart cards are however vulnerable to side channel attacks. Power consumption and electromagnetic radiation of the smart card can leak information about the secret data protected by the smart card. Our paper describes two possible hardware countermeasures that protect against side channel information leakage. We show that power analysis can be prevented by adopting photo-coupling techniques. This method involves the use of LED with photovoltaic cells and photo-couplers on the power, reset, I/O and clock lines of the smart card. This method reduces the risk of internal data bus leakage on the external data lines. Moreover, we also discuss the effectiveness of reducing electromagnetic radiation by using embedded metal plates.

A periodically loaded ultra wideband (UWB) bandpass filter based on the electromagnetic band-gap (EBG) concept is presented. Compact wideband filters with steep transition bands can be designed easily using this novel methodology. Unit cells in the EBG circuit model are realized by capacitive and inductive parallel loading of a transmission line. These unit cells are cascaded to realize bandpass filters whose bandwidth depends on the reactive loading of unit cells. The number of unit cells determines the steepness of the band edges of the filter. The main advantage lies in the fact that the size of unit cells can be small because electrical length of transmission line segments in unit cells can be chosen arbitrarily, hence the final filter structure becomes small in size. A microstrip filter with 60% bandwidth is designed and the physical size is compared with a conventional wideband bandpass filter designed with quarter wavelength admittance inverters.

To evaluate whether electromagnetic disturbances that leak from PC displays contain information or not, we need to reconstruct the information from the measured disturbance. This requires a special receiver, and not all test houses have a special receiver. In this paper, we propose performing the evaluation with the spectrum analyzers commonly used for EMI measurement. First, we select a spectrum that containing the frequency component of the vertical sync signal using a spectrum analyzer (SA1). Then, we measure the video output of SA1 using another spectrum analyzer (SA2) and evaluate the disturbance from the frequency component of the horizontal sync signal.