A new type of permanent magnet actuator driven by electromagnetic repulsive force in breaking course and electromagnetic attraction force during closing course is presented in this paper, and the static and dynamic characteristics for contactor with this new type actuator are mainly focused on by simulation and experiment simultaneously. Firstly, the static electromagnetic attraction force in closing course and electromagnetic repulsive force in breaking course are studied by FEM simulation and experiment. Secondly, by coupling of the electrical and mechanical differential equations, the dynamic electromagnetic attraction force in closing course and dynamic electromagnetic repulsive force in breaking course are obtained respectively. Thirdly, by constructing the mechanical model of contact system and permanent magnet actuator, the displacements of moving contact and moving core while both contactors' closing and breaking are obtained by simulation and experimental study. It is indicated that simulation results coincide well with that of experiment.

A microstrip phase shifter design that uses a reconfigurable metal pattern on the EBG ground plate is introduced. The EBG ground plate metal pattern contains a linear array of thin slots with switching devices loaded at the center. This design can vary the phase constant with minimum mismatch loss over a large frequency bandwidth. Several test ground plates without actual switching devices were used to verify the design concept.

This paper presents a modal-expansion analysis of the electromagnetically coupled coaxial dipole antenna. The analysis of the antenna problem is initially simplified using the even-odd mode excitation and then the resultant half structure is divided into two parts; one is the characterization of a coaxial feeding network and the other is the modeling of a sleeve monopole antenna driven by a coaxial line. The formally exact modal-expansion method is employed to analyze both parts. The analysis of the sleeve monopole antenna is facilitated by introducing a perfectly conducting boundary at a distance from the monopole's top end. The current distribution and input impedance of the electromagnetically coupled coaxial dipole antenna are obtained by finding expansion coefficients through enforcing the continuity of tangential field components across regional interfaces and cascading the two parts together. Numerical results for the coaxial dipole antenna's radiation characteristics are presented and discussed.

This paper describes a two-dimensional clustering scheme-based analysis of audible noises induced at telephone terminals. To analyze EMI sources that cause telephone-audible noise, we use a self-organizing map, which provides a way to map high-dimensional data onto a two-dimensional domain. Also, in order to discriminate EMI sources without using particular resonance frequencies that have peaks in the frequency domain, we use the energy spectra of telephone-audible noises as input for training the self-organizing map. In applying this method in actual environments, we measured ten kinds of telephone-audible noises (due to Radio waves and cross-talk noises, etc.) and then derived their energy spectra for eight frequency bands: 1-250 Hz, 250-500 Hz, 500-1 kHz, 1 k-1.5 kHz, 1.5 k-2 kHz, 2 k-3 kHz, 3 k-4 kHz, and over 4 kHz. We visually confirmed that the measured telephone-audible noise data could be projected onto the map in accordance with their properties, resulting in a combined depiction of the composition of derived energy spectra in the frequency bands. The proposed method can deal with multi-dimensional parameters, projecting its results onto a two-dimensional space in which the projected data positions give us an effective depiction of EMI sources that cause disturbances at telephone terminals.

In this paper, the magnetic field properties and the dosimetry at intermediate frequency (21 kHz) for an induction heater are investigated with the coil model, which is prescribed as substitute source model in the European standard EN50366 (CENELEC). The accuracy of the magnetic field vectors and the values of the induced current density, which are achieved with the coil model, are compared with the results of a realistic model of the induction heater obtained from the equivalent source model. It is shown that the coil model coincides well for the magnitude of the magnetic field strength around the induction heater. On the other hand, the dominant field vector of the coil model differs significantly from the real induction heater, which leads to induced current densities in the body model which are three time larger. Owing to these results, the applicability of the coil model prescribed in the EN50366 is confirmed for the induction heater.

This paper proposes a parallel coupled microstrip bandpass filter (BPF) with ring Electromagnetic Bandgap (EBG) cells on the middle layer for spurious suppression. The ring EBG cells of the middle layer add a good stopband-rejection mode to the second harmonics of the parallel coupled microstrip BPF with suppression of over -50 dB, without affecting the center frequency and insertion loss of the original designed BPF. The design of ring EBG cells is presented and verified by the experimented results.

A new approach used to formulate to mixed-path propagation of surface wave is presented based on two main ingredients: the decomposition of electromagnetic fields and the introduction of equivalent electric (magnetic) currents adopted for convenience. The present method can be extended to obtain the corresponding results for the arbitrary incident wave excitation.

Techniques of near-field magnetic measurement and their applications to EMC of digital equipment are described. Magnetic-field measurement near PCB or LSI is the mostly used technique to specify the source. This paper treats an example of board analysis by near-field magnetic measurement, the sensing mechanism and the structure of a loop probe, and a recent progress of this method and application. To establish appropriate design direction in high-speed and high-density packaging of electronic equipment, electromagnetic behavior in chip and package should be clarified. Expectation of development for measuring minute area is more and more increasing.

The effect of a grounded conductive sheet placed over a PCB with a microstrip line on the electromagnetic noise shielding is discussed experimentally and with FDTD modeling. The grounding position of the sheet, which is connected with the ground plane of PCB, is changed. In results, the resonance frequency is shifted by the grounding position, and reducing the resonance of the input impedance should make a more effective shielding for EM noise radiation below 1 GHz.

A free-space method is in wide spread use for the reflectivity measurement of electromagnetic wave absorbers (EMA) in VHF and UHF range. In the free-space method, the reflection levels from EMA and from the metal plate with same size as the EMA are measured, and the reflectivity is calculated from their ratio. The incident angle such as normal or oblique must be defined, and the polarization of electromagnetic (EM) wave must be specified to be TE, TM, or circularly-polarized mode. In this paper, a parallel EM wave beam method using dielectric lenses in front of horn antennas was studied experimentally. Electromagnetic wave absorption was measured with the vertical and the oblique incidence by using this parallel EM wave beam. This measurement system has following features:• It is compact because equiphase parallel EM wave beam was obtained in a short distance from the dielectric lens.• It requires no anechoic chamber because of little multi-reflection due to high directivity of parallel EM wave beam.• It allows a large oblique incident measurement by using high directive parallel EM wave beam.

This letter proposes the thinnest hybrid EM wave absorber using a composite magnetic material, which can be applied to the 3 m semi anechoic chambers. We experimentally designed a new hybrid EM wave absorber of the wedge shape, which was made from the ferrite powder, the inorganic fiber and binder. As a result, the length of this absorber could be realized only 6 cm, which was ascertained having the nonflammable. The 3 m semi anechoic chamber is constructed in the size of L9 mW6 mH5.7 m using this absorber, and then the site attenuation is measured according to ANSI C63.4 in the frequency range of 30 MHz-1 GHz. As a result, the measured normalized site attenuation is obtained within 3 dB to the theoretical normalized site attenuation.

Finding intracranial aneurysms plays a key role in preventing serious cerebral diseases such as subarachnoid hemorrhage. For detection of aneurysms, magnetic resonance angiography (MRA) can provide detailed images of arteries non-invasively. However, because over 100 MRA images per subject are required to cover the entire cerebrum, image diagnosis using MRA is very time-consuming and labor-intensive. This article presents a computer-aided diagnosis (CAD) system for finding aneurysms with MRA images. The principal components are identification of aneurysm candidates (= ROIs; regions of interest) from MRA images and estimation of a fuzzy degree for each aneurysm candidate based on a case-based reasoning (CBR). The fuzzy degree indicates whether a candidate is true aneurysm. Our system presents users with a limited number of ROIs that have been sorted in order of fuzzy degree. Thus, this system can decrease the time and the labor required for detecting aneurysms. Experimental results using phantoms indicate that the system can detect all aneurysms at branches of arteries and all saccular aneurysms produced by dilation of a straight artery in 1 direction perpendicular to the principal axis. In a clinical evaluation, performance in finding aneurysms and estimating the fuzzy degree was examined by applying the system to 16 subjects with a total of 19 aneurysms. The experimental results indicate that this CAD system detected all aneurysms except a fusiform aneurysm, and gave high fuzzy degrees and high priorities for the detected aneurysms.

A new shielding evaluation setup for conductive O-rings is proposed. This setup consists of the holder with a groove to fix the O-ring position. There are two ways to apply O-rings in narrow gaps, cylinder-fixing and plane-fixing. With this holder shielding effects of the O-rings can be evaluated from 10 kHz to 1 GHz for both fixing types.

An inverse scattering problem of estimating the surface impedance for an inhomogeneous half-space is investigated. By virtue of the fact that the far field representation contains the spectral function of the scattered field, complex values of the function are estimated from a set of absolute values of the far field. An approximate function for the spectral function is reconstructed from the estimated complex values by the least-squares sense. The surface impedance is estimated through calculating the field on the surface of the half-space expressed by the inverse Fourier transform. Numerical examples are given and the accuracy of the estimation is discussed.

Unwanted electromagnetic emission occurs due to the common-mode current on the cables entering a PC's metal enclosure and can be treated as wire antennas passing through the apertures of the enclosure. To reduce the emission, a stack of metal rings is suggested to be placed around the cable and external to the aperture, adopting the concept of a Coaxial Band-Stop Filter, for the first time. The influence of this novel structure on the common-mode current is examined in the FDTD-method frame work.

A TMTR code is specified as (=2,=3,k) constraint. In this work, an approach for constructing (=2,=3,k) codes is presented. Based on this construction, a rate 8/9 code with k=7 is found. This code can achieve better timing recovery performance compared to the proposed previously TMTR code with k=11. An enumerating encoder and decoder exist for constructed (=2,=3,k) codes. A look-up table for the encoder/decoder is not required. Simulation results on an E2PRIV recording channel reveal that the TMTR code provides 2.2 dB gain over an uncoded case.

We demonstrate a novel fiber device exhibiting magnetic circular dichroism (MCD) and Faraday rotation in sharpened optical fibers coated with Fe. The degree of MCD was 0.68 in a magnetic field of 0.35 T and the Faraday rotation angle was as great as 110 degrees. Such great magneto-optical effect is due to optical near-field interactions in the sub-wavelength region, i.e., in the tip of the near-field fiber probe. These effects can be attributed to the large magnitude of the magneto optical coefficient of Fe.

The measured values of electromagnetic disturbances should strongly correlate with degradation in the communication quality of digital wireless communication systems. The Amplitude Probability Distribution (APD) of a disturbance represents statistical information as applicable measurement readings that meet the above requirement. In this paper, correlations between APD measurements of disturbances and the bit error rate (BER) as a quality degradation index for victim systems are quantitatively investigated. Disturbance regulation by APD measurements is discussed from the viewpoint of protecting systems from disturbances. This investigation specifically considers the situation in which a repetition pulse disturbance impacts PHS and W-CDMA systems assumed as victims. The results confirm high correlations between the APD and BER not only experimentally but also theoretically under some conditions. A disturbance regulation criterion based on APD measurements is thus proposed for compliance testing of electronic appliances with the potential to act as disturbance noise sources.

We have studied on the interference test method from IEEE802.11b to IEEE802.11g as an interference source with wide band spectrum by using the opened PW cell, and it is clear that the throughput of IEEE802.11g for only IEEE802.11b Ch.4 signal wave as the interference wave, whose frequency spectrum is almost not overlapping with IEEE802.11g, is almost not interfered by IEEE802.11b, but the throughputs for all other channels from Ch.5 to Ch.8 as the interference wave are interfered and decrease to below 2 Mbps. By comparing with conventional radiated RF electromagnetic field immunity test specified by IEC 61000-4-3, it is clear that the conventional immunity test cannot simulate the interference phenomena from IEEE802.11b to IEEE802.11g. Next, we tried to perform the interference test of the Bluetooth against the wireless LAN IEEE 802.11b as a disturbance source. As a result, it is revealed that the throughput of Bluetooth decreases according to increasing the interference wave level, and communication between EUT (slave) and the master of Bluetooth is interrupted for the interference wave corresponding to Ch.7 (244210 MHz). However, in the conventional immunity test specified by IEC 61000-4-3, the throughput of the Bluetooth does not affect for the all disturbance waves corresponding to the center frequency of bandwidth on the cannel of IEEE802.11b. Therefore, it is needed for the wireless LAN and the Bluetooth to develop new radiated immunity test method, which has the disturbance wave with wide bandwidth.

We study radiated RF (radio-frequency) electromagnetic field immunity test system for wireless LAN system by using opened PW (Parallel Wired) cell, in which metal cover is removed. Leakage electric field at distance of 160 cm from the opened PW cell decreases until 30 dB, and then does not affect to operation of the AP (Access Point) composed of the wireless LAN system that communicates EUT (Equipment Under Test) installed in the PW cell. NSA (Normalized Site Attenuation) between EUT and AP changes only several dB by inserting the PW cell, and then it can be concluded that the effect of PW cell for radio wave property of wireless communication system is negligible small. In addition, we try to measure dependencies of impressing level of disturbance wave on a throughput of wireless LAN systems IEEE802.11b and IEEE802.11g. As a result, it is confirmed that the radiated RF electromagnetic field immunity test system for wireless LAN system can be composed by using the opened PW cell without affecting from impressing disturbance wave.