In this paper, a novel method of partially placing electromagnetic band-gap (EBG) unit cells on both the power and ground planes in multi-layer PCBs and packages is proposed; it can not only sufficiently eliminate simultaneous switching noise (SSN), but also prevent severe degradation of signal quality in high-speed systems with imperfect reference planes resulting from the perforated structures of uni-planar EBG unit cells. On the assumption that the noise sources and noise-sensitive devices exist only in specific areas, the proposed method partially arranges the EBG unit cells on both the power and ground planes, but only around the critical areas. The SSN suppression performance of the proposed structure is verified by a simulation and measurements.

The Dst index is the most popular measure of a scale of magnetic storms, and it is widely used as a monitor of the conditions of the Earth's magnetosphere. Since the Dst index contains contributions from multiple magnetospheric phenomena, it is important to distinguish each of the contributions in order to obtain meaningful information about the conditions of the magnetosphere. There have been several efforts which modeled temporal evolution of the Dst index empirically, and these empirical models considers some contributions separately. However, they take only short-term varations into accout, and contributions from phenomena which show long-term variations are neglected. In the present study, we have developed a technique for estimating the component of long-term variations of the Dst index using solar wind data and a nonlinear empirical model. The newly-developed technique adopts an algorithm which is similar to the particle filter. This algorithm allows an on-line processing of a long sequence of Dst data, which would enable a real-time estimation of system variables in a nonlinear system model. The estimates of the long-term variations can be used for accurate estimation of other contributions to the Dst index, which would provide credible information about the conditions of the magnetosphere. The framework proposed in the present study could be applied for the purpose of continuous real-time monitoring of the environment of the magnetosphere.

Printed circuit boards (PCBs) driven by a connected feed cable are considered to be one of the main sources of the electromagnetic interference (EMI) from electronic devices. In this paper, a method for predicting the electromagnetic (EM) radiation from a PCB driven by a connected feed cable at up to gigahertz frequencies is proposed and demonstrated. The predictive model is based on the transmission line theory and current- and voltage-driven CM generation mechanisms with consideration of antenna impedance. Frequency responses of differential-mode (DM) and common-mode (CM) currents and far-electric field were investigated experimentally and with finite-difference time-domain (FDTD) modeling. First, the dominant component in total EM radiation from the PCB was identified by using the Source-Path-Antenna model. Although CM can dominate the total radiation at lower frequencies, DM is the dominant component above 3 GHz. Second, the method for predicting CM component at lower frequencies is proposed. And its validity was discussed by comparing FDTD calculated and measured results. Specifically, the relationship between the CM current and the terminating resistor was focused as important consequence for the prediction. Good agreement between the measured and predicted results shows the validity of the predicted results. The proposed model can predict CM current with sufficient accuracy, and also identify the primary coupling-mechanism of CM generation. Then far-electric field was predicted by using the proposed method, and it was demonstrated that outline of the frequency response of the undesired EM radiation from the PCB driven by the connected feed cable can be predicted with engineering accuracy (within 6 dB) up to 18 GHz. Finally, as example of application of equivalent circuit model to EMC design, effect of the width of the ground plane was predicted and discussed. The equivalent circuit model provides enough flexibility for different geometrical parameters and increases our ability to provide insights and design guidelines.

A transmission line created by cables adjoined by connectors is influenced by noise from connectors with contact failure, and such noise degrades communication quality. The authors used a model of a connector with increased contact resistance in a coaxial cable and measured the electromagnetic near-field around a cable while changing positions of the model. In this paper, the result shows that the radiated electromagnetic field has no relationship with the position along the cable of a connector with increased contact resistance, when the contact condition of connector, contact resistance value, measurement position, and length of a transmission line are constant.

This paper describes an analysis of the effects of electric field on nerve cells by using the Hodgkin-Huxley model. When evaluating our model, which combines an additional ionic current source and generated membrane potential, we derive the peak-to-peak value, the accumulated square of variation, and Kolmogorov-Sinai (KS) entropy of the cell-membrane potential excited by 10, 100, 1 k, and 10 kHz-sinusoidal electric fields. In addition, to obtain a comprehensive view of the time-variation patterns of our model, we used a self-organizing map, which provides a way to map high-dimensional data onto a low-dimensional domain. Simulation results confirmed that lower-frequency electric fields tended to increase fluctuations of the cell-membrane potential, and the additional ionic current source was a more dominant factor for fluctuations of the cell-membrane potential. On the basis of our model, we visually confirmed that the obtained data could be projected onto the map in accordance with responses of cell-membrane potential excited by electric fields, resulting in a combined depiction of the effects of KS entropy and other parameters.

To build a stable power distribution network for high-speed digital systems, simultaneous switching noise (SSN) should be sufficiently suppressed in multi-layer PCBs and packages. In this paper, a novel hybrid uni-planar compact electromagnetic bandgap (UC-EBG) with two triangular-type unit cells designed on power/ground planes is proposed for the ultra-broadband suppression of SSN. The SSN suppression performance of the proposed structure is validated both numerically and experimentally. A -35 dB suppression bandwidth for SSN is achieved, starting at 800 MHz and extending to 15 GHz and beyond, thereby covering almost the entire noise band.

In this letter, we propose a novel approach using wireless sensor networks (WSNs) to enhance the safety and efficiency of four-way stop-sign-controlled (FWSC) intersections. The proposed algorithm provides right of way (RoW) and crash avoidance information by means of an intelligent WSN system. The system is composed of magnetic sensors, embedded in the center of a lane, with relay nodes and a base station placed on the side of the road. The experimental results show that the vehicle detection accuracy is over 99% and the sensor node battery life expectancy is over 3 years for traffic of 5,800 vehicles per day. For the traffic application we consider, a strong effect is observed as the projected conflict rate was reduced by 72% compared to an FWSC intersection operated with only driver perception.

The observed phenomena in actual sound and electromagnetic environment are inevitably contaminated by the background noise of arbitrary distribution type. Therefore, in order to evaluate sound and electromagnetic environment, it is necessary to establish some signal processing methods to remove the undesirable effects of the background noise. In this paper, we propose noise cancellation methods for estimating a specific signal with the existence of background noise of non-Gaussian distribution from two viewpoins of static and dynamic signal processing. By applying the well-known least mean squared method for the moment statistics with several orders, practical methods for estimating the specific signal are derived. The effectiveness of the proposed theoretical methods is experimentally confirmed by applying them to estimation problems in actual sound and magnetic field environment.

Liquid-phase detection of biological targets utilizing magnetic marker and superconducting quantum interference device (SQUID) magnetometer is shown. In this method, magnetic markers are coupled to the biological targets, and the binding reaction between them is detected by measuring the magnetic signal from the bound markers. Detection can be done in the liquid phase, i.e., we can detect only the bound markers even in the presence of unbound (free) markers. Since the detection principle is based on the different magnetic properties between the free and bound markers, we clarified the Brownian relaxation of the free markers and the Neel relaxation of the bound markers. Usefulness of the present method is demonstrated from the detection of the biological targets, such as biotin-coated polymer beads, IgE and Candida albicans.

This paper presents the computational electromagnetic dosimetry inside an anatomically based pregnant woman models exposed to electromagnetic wave during magnetic resonance imaging. The two types of pregnant woman models corresponding to early gestation and 26 weeks gestation were used for this study. The specific absorption rate (SAR) in and around a fetus were calculated by radiated electromagnetic wave from highpass and lowpass birdcage coil. Numerical calculation results showed that high SAR region is observed at the body in the vicinity of gaps of the coil, and is related to concentrated electric field in the gaps of human body such as armpit and thigh. Moreover, it has confirmed that the SAR in the fetus is less than International Electrotechnical Commission limit of 10 W/kg, when whole-body average SARs are 2 W/kg and 4 W/kg, which are the normal operating mode and first level controlled operating mode, respectively.

A microwave resonator is fabricated by a lump of spherical metal particles for the first time. It is the evidence that those particles constitute artificial dielectrics. The effective permittivity is calculated numerically together with the permeability. Resonant mode frequencies in the experiment are compared with the theoretical result obtained by the effective material constants above. Their reasonable agreement indicates the validity of material constant extraction. The unique diamagnetism of spherical particles could be utilized for improvement of spurious property of a resonator.

An inverse scattering problem of estimating the reflection coefficient and the surface impedance from two sets of absolute values of the near field with periodic change is investigated. The problem is formulated in terms of a nonlinear simultaneous equations which is derived from the relation between the two sets of absolute values and the field defined by a finite summation of the modal functions by applying the Fourier analysis. The reflection coefficient is estimated by solving the equations by Newton's method through the successive algorithm with the increment of the number of truncation in the summation one after another. Numerical examples are given and the accuracy of the estimation is discussed.

In this paper, we design and manufacture a flanged double ridged waveguide with a tapered section as a sample holder for measuring the electromagnetic shielding effectiveness (SE) of planar material in broadband frequency ranges up to 10 GHz. The proposed technique overcomes the limitations of the conventional ASTM D4935 test method at high frequencies. The simulation results for the designed sample holders agree well with the fabricated ones in consideration of the design specification of S11 < -20 dB within the frequency range of 1-10 GHz. To verify the proposed measurement apparatus, the measured SE data of the commercial shielding materials from 1 to 10 GHz were indirectly compared with those obtained from the ASTM D4935 from 30 MHz to 1 GHz. We observed that the SE data obtained by using both experimental techniques agree with each other.

Ultra wideband (UWB) technologies are expected to be used in ultra-high-speed wireless personal area networks (WPAN) and wireless body area networks (WBAN). UWB human electromagnetic phantoms are useful for performance evaluation of antennas mounted in the vicinity of a human body and channel assessment when a human body blocks a propagation path. Publications on UWB phantoms, however, have been limited so far. This paper describes the development of liquid UWB phantom material (aqueous solution of sucrose) and UWB arm and torso phantoms. The UWB phantoms are not intended to evaluate a specific absorption rate (SAR) in a human body, because UWB devices are supposed to transmit at very low power and thus should pose no human hazard.

Experimental and theoretical studies of light coupling to various magnetic nanostructured media and nanocomposites are briefly reported. Enhancement of the magneto-optical response is shown to occur when the constitutive materials of photonic crystals are magnetic. Transmission and reflection types of 1D magnetophotonic crystals (MPCs) have been studied. New possibility to enhance the magneto-optical response has been found when utilizing localized surface plasmon resonances in bismuth-substituted yttrium iron garnet (Bi:YIG) films impregnated with Au nanoparticles. Examples of integrated optic devices are discussed in which functional elements are 1D and 2D magnetophotonic crystals.

Rugate thin film optical filters are useful for designing arbitrary-shaped spectra, such as multistep or triangular spectra. A technique for synthesizing the refractive index distribution of rugate filters was used to suppress unwanted ripples on the spectrum. The refractive index of an amorphous hydrogenated silicon oxide (a-SiOx:H) rugate thin film was minutely controlled with a resolution of 0.001 using radio-frequency (RF) magnetron sputtering. The fabricated rugate filters had multistep bands over a wavelength range of 1260-1670 nm or good linearity over 1290-1650 nm.

Ga-doped ZnO thin films were prepared by RF magnetron sputtering. The effects of adding H2 to pure Ar sputtering gas were investigated. In the case of pure Ar at 2 Pa, the resistivity is 7.4510-3 Ωcm, whereas for Ar+1%H2 at 0.3 Pa, it markedly decreases to 2.5210-4 Ωcm. In this case, the carrier density and Hall mobility are 1.121021 cm-3 and 23.4 cm2/Vs, respectively. This conductive film also exhibits a transmittance of 90% within the visible-wavelength range. The addition of H2 and the decrease in the pressure results in the fabrication of a significantly more transparent and conductive film.

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.

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.

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.