Electromagnetic noise radiated from microwave ovens may cause serious interference problems in wireless systems using the 2.4-GHz band. Since oven noise waveforms show strong dependence on the frequency selectivity of the receiver filters, the effect of band limitation on the interfering oven noise is an important issue for evaluating or comparing the performance degradation of wireless systems subject to interference. To understand these effects, theoretical and experimental investigations of the waveform, peak amplitude, and pulse width of band-limited oven noise are carried out. It is found that the peak amplitude of the received noise changes with the bandwidth in a way very similar to the case of a simple RF tone-burst input. The pulse width of the received noise also changes with the receiver bandwidth but takes a minimum value at a certain receiver bandwidth, which is an essential feature of band-limited microwave oven noise. In addition, an appropriate resolution bandwidth is determined for using a spectrum analyzer to obtain accurate oven noise parameters.

Unloaded Q of a dielectric image resonator is discussed based on the electromagnetic field distribution. It is shown that a partial air gap and a dielectric sheet with low permittivity between the dielectric resonator and the shield case reduce both the dielectric loss and the conductor loss. Especially, reduction of the conductor loss is significant, since the magnetic field distribution moves from the conductor to the upper part of resonator. A half-cut image resonator with an air gap and dielectric spacer is simulated and measured. The unloaded Q of the dielectric resonator with low dielectric loss is improved by about two times from that of original image resonator.

The use of metal-coated plastics is increasing as shielding materials of electronic and information products due to their lightweight. In this paper, a finite-difference time-domain (FDTD) algorithm, based on the derivation of a time-domain representation of the surface impedance of an equivalent resistive film, was developed to analyze the electromagnetic penetration of pulsed electromagnetic fields through metal-coated plastics. The validity of the proposed algorithm, in both the far-field and near-field cases, was verified by comparing the calculated penetrated electromagnetic fields or shielding effectiveness with theoretical and measured ones. Good agreement between them demonstrated the usefulness of the FDTD algorithm.

Newly designed cyclometalated iridium phosphors bearing 2,3-diphenylquinoxalines were characterized to provide highly efficient and vivid-red emitting materials for electrophosphorescent organic light-emitting devices. Excellent quantum efficiencies for photoluminescence (PL) within a range 50-79% were observed in dichloromethane solutions at room temperature. A greatly improved PL decay lifetime of 1.1 µsec was also observed in CBP coevaporated film. Luminescence peak wavelengths of the phosphors lay within a preferable range 653-675 nm in evaporated films. The most vivid-red electroluminescence with 1931 CIE chromaticity coordinates of (x=0.70, y=0.28) was successfully attained.

This paper presents a performance comparison between carrier interferometry coded OFDM (CI/COFDM) and typical coded OFDM (COFDM) using multiple receive antennas. The feature of CI/COFDM with diversity reception is to combine the time diversity benefit introduced by channel coding with the frequency and space diversity benefits created by frequency-domain equalization (FDE). Simulation results for QPSK showed that, at the perfect channel estimation, CI/COFDM outperforms COFDM under frequency and time selective fading channels because of the powerful time diversity benefit introduced by channel coding with time interleaving. However, at the imperfect channel estimation, this advantage of CI/COFDM over COFDM becomes very limited.

This paper presents a new type of optical probe designed to detect magnetic near-fields with high accuracy in the gigahertz range. Its probe head consists of a loop antenna element doubly loaded with LiNbO3 electro-optic crystals. Through an optical technique, it can work as a conventional double-loaded loop probe without metallic cables or an electrical hybrid junction. We examined probe characteristics for magnetic field detection up to 20 GHz. We confirmed that the probe can measure magnetic fields near a microstrip line in the gigahertz range and can suppress influence of electric fields.

Direct digital frequency synthesizers (DDFS) provide fast frequency switching with high spectral purity and are widely used in modern spread spectrum wireless communication systems. ROM-based DDFS uses a ROM lookup table to store the amplitude of a sine wave. A large ROM table is required for high spectral purity. However, a larger ROM uses more area and consumes more power. Several ROM compression methods, including Sunderland technique based on simple trigonometric identities and quantization & error compensation techniques, have been reported. In this paper, we suggest several new techniques to reduce the ROM size. One new technique uses more number of hierarchical levels in ROM structures. Another technique uses simple interpolation techniques combined with hierarchical ROM structures. Experimental results show that the new proposed techniques can reduce the required ROM size up to 24%, when compared to that of a resent approach.

The relation between resonant frequency of micromirror with vertical combdrives and applied voltage between the upper and lower comb teeth was analyzed. Resonant frequency of the micromirror was controlled by stiffness of the torsion hinge. Resonant frequency of the mirror was proportional to the applied voltage between the upper and lower comb teeth at the same tilt angle.

We describe elements of a fast integral equation solver for large periodic and partly periodic finite array systems. A key element of the algorithm is utilization (in a rigorous way) of a block-Toeplitz structure of the impedance matrix in conjunction with either conventional Method of Moments (MoM), Fast Multipole Method (FMM), or Fast Fourier Transform (FFT)-based Adaptive Integral Method (AIM) compression techniques. We refer to the resulting algorithms as the (block-)Toeplitz-MoM, (block-)Toeplitz-AIM, or (block-)Toeplitz-FMM algorithms. While the computational complexity of the Toeplitz-AIM and Toeplitz-FMM algorithms is comparable to that of their non-Toeplitz counterparts, they offer a very significant (about two orders of magnitude for problems of the order of five million unknowns) storage reduction. In particular, our comparisons demonstrate, that the Toeplitz-AIM algorithm offers significant advantages in problems of practical interest involving arrays with complex antenna elements. This result follows from the more favorable scaling of the Toeplitz-AIM algorithm for arrays characterized by large number of unknowns in a single array element and applicability of the AIM algorithm to problems requiring strongly sub-wavelength resolution.

Hierarchical Mobile IPv6 (HMIPv6) has been proposed to manage the mobility of Mobile Terminals (MTs) hierarchically to reduce packet losses during local handover. HMIPv6 uses a mobility manageable router in a domain visited by the MTs to manage the micromobility of the MTs. The router is called Mobility Anchor Point (MAP). As a hierarchical mobility management scheme based on HMIPv6, we have already proposed a multilevel hierarchical distributed IP mobility management scheme to manage the mobility of MTs in a decentralized manner using multiple MAPs. Our scheme manages the mobility of an MT using a MAP having a suitable management domain. This usage of MAPs aims to efficiently decentralize the load of mobility management. Our scheme estimates the movement speed of the MT and then estimates the mobility of the MT based on the estimated movement speed of the MT to achieve the objective. However, recent simulation results obtained with more realistic mobility model indicate that our scheme has two problems in estimating the mobility of MTs: One is that our current scheme misestimates the movement speed of an MT in some cases, and the other is that our current scheme does not notice the changes in the mobility of an MT when the MT decelerates and stays in the same access area for a long time. Thus, an enhanced mobility estimation method is proposed in this paper. The enhanced method has an ability to estimate the movement speed of MTs more correctly and an ability to urge decelerated MTs to degrade their MAP quickly. Finally, the performance of the proposed mobility estimation method is evaluated using simulation experiments. The simulation results show that the enhanced method allows our scheme to estimate the mobility of MTs more correctly and so achieve more efficient load sharing.

Common-mode (CM) current on a feed cable attached to printed circuit board (PCB), which is one of main source of undesired electromagnetic radiation problem, is investigated by experimental and finite-difference time-domain (FDTD) modeling. In this paper, frequency responses of CM current on PCB and feed cable are modeled and analyzed as an electromagnetic interference (EMI) antenna, which depends on the configuration of PCB with a wire cable. Several different configurations are prepared to demonstrate the effect of PCB dimension on resonance frequencies of CM current. In the results, EMI antenna in the frequency band around the first resonance frequency was comprised of the ground plane and cable. In order to explain the frequency response of CM current, two EMI antenna models are proposed and demonstrated. EMI antenna is comprised of the ground plane and cable, and the other EMI antenna is comprised of the trace on the ground plane. It is suggested that the result is one of basic consideration for the ground plane with cable that have high EMI problem and resonance frequency of CM current.

A high-attenuation waveguide filter using electromagnetic bandgap (EBG) substrates is introduced. With a simple design modification on the EBG covers, the waveguide filter produced an almost full Ku-band rejection bandwidth showing better than 20 dB input-to-output isolation from 12.3 to 17.2 GHz.

Various effective and draft legislations and rules in Europe (WEEE--Waste Electrical and Electronic Equipment ROHS--Restrictions on the use of certain substances and ELV--End of life of vehicles) and Japan (Recycling Law for Home Electric Appliances) have either targeted restrictions or fully banned on the use of lead, to be enforced from 2001, 2003 and 2006 onwards. Up to now, mainly tin-lead alloys have been used in electronics. The process temperatures usually applied have been in the range of 230. All currently discussed lead-free alternatives for professional electronics need process temperatures which are at least 20 higher. In addition, the process duration is significantly longer. The combination of higher process temperatures and longer duration results in significant thermal stress on electromechanical devices. In particular the precision mechanics of electromechanical relays must withstand the solder process with maximum process temperatures of 255 without dimensional changes. During the transition from tin-lead to lead-free solder processes all combinations of component surfaces and solder must be possible. The selection of pure Sn100 or SnCu0.7 as terminal surface allows mixed assemblies with tin-lead as well as lead-free solders. All tested combinations of terminal surface, PCB surface and solder showed good results. From these results it can be concluded that mixed assemblies are possible during the transition time without any negative impact on the reliability of the electronic devices.

The lithography process on the deep trench pattern above the large cavity is proposed to fabricate the MEMS structure. Generally, bubbles generated on the trench patterns when it was baked after coating resist. The probability of the generation of bubbles was reduced by decreasing the backing rate. The fast scanning micromirror with 50.8 kHz resonant frequency was fabricated by controlling the backing rate.

The effect of the structure with difference on cross-section for the enlarged models that simulates signal transmission line (STL) in the magnetic head of HDD is discussed. The experimental results suggested that strip and shield structure are effective for suppression of EMI.

Shared memory multiprocessors in which each processor has its own TLB must manage consistency among TLBs and a page table. As the large-scale CC-NUMA (cache-coherent non-uniform memory access) shared memory multiprocessors become popular, it is important for TLB consistency management algorithms to be highly scalable. In this paper, we propose a TLB update-hint algorithm as a scalable TLB consistency management solution for CC-NUMA multiprocessors. By using a lazy TLB invalidation approach, we reduced the number of unnecessary processor interruptions and idle-waiting time, and achieved a high level of scalability. Using a shared memory simulator, we evaluated the TLB update-hint algorithm. For performance comparison, we also simulated the TLB shootdown algorithm, one of the most popular TLB consistency algorithms. The simulations demonstrated that the TLB update-hint algorithm scales well in systems with a large number of processors. At 64 node systems, the TLB update-hint algorithm shows 4787% better performance than the TLB shootdown algorithm.

This paper presents the realization of the radio frequency (RF) power and data transmission for implantable microstimulators. This implantable device composes an internal RF front-end circuit, a control circuit, and a microstimulator. A 2 MHz AM-modulated signal including the power and data necessary for the implantable device is received, and a stable dc voltage and digital data will be extracted to further stimulate neuromuscular stimulation. In this implantable stimulator, the digital part is implemented by field programmable gate array (FPGA), and the analog part is implemented in a standard single-poly fifth-metal 0.25 µm CMOS process. The latter occupies a silicon area smaller than 0.00638 mm2 and produces an output current with 5-bit resolution for stimulations. The measuring stimulating current is 2.77 mA while the stimulation frequency is from 20 Hz to 2 kHz and the pulse width of stimulation current is from 100 µs to 450 µs. In addition, the simulation results of the RF front-end circuit and the verification of the control logic circuit are also presented in this paper.

In this paper, a simple and practical corresponding-color reproduction model based on the chromatic adaptation of the human visual system (HVS), named a modified von Kries chromatic-adaptation model, is proposed for TV and PC monitors under a variety of viewing conditions. We derived the proposed corresponding-color reproduction model based on Breneman's corresponding-color data. The proposed model has a 1-2% less error than Fairchild's and Breneman's model, 11.5% less error than von Kries' model and 60% less error than CIECAM97s' model in terms of color reproduction errors, (). Also, these tendency is similar in color reproduction errors, . We implemented a corresponding-color reproduction system using the proposed model under a variety of viewing conditions. For the determination of viewing conditions, illuminant correlated color temperatures (CCTs) are measured by yellow/cyan sensors. These measured surround illuminant CCTs can estimate an adaptated neutral point of the HVS in TV viewing conditions. Experiments were carried out to assess the proposed model performance in terms of color fidelity by comparing complex images on a LCD monitor under illuminants from 2500 K to 7500 K. We confirmed that the implemented system using the proposed model can predict corresponding-color data very well under a variety of viewing conditions. Therefore, by applying the proposed model and system to the LCD, the reproduction colors viewed in real surrounding viewing conditions on the LCD could appear the same as the original object colors under standard viewing conditions. Furthermore, they could be applied to any other color display device such as a CRT, a PDP, and a DLP in order to get better reproduction colors.

This paper presents an imaging technique using the MUSIC algorithm to localize cylindrical reflectors in cross-borehole radar arrangements. Tomographic measurement, in which a transmitting and a receiving antenna are individually moved in separate boreholes, can be considered as a combination of a transmitting and a receiving array. A decorrelation technique with the transmitting array, which has been proposed for imaging point reflectors, is applied for imaging cylindrical reflectors using the MUSIC algorithm. Simulated and experimental results are shown to verify the validity of this algorithm for cylindrical targets. We analyze the evaluation error caused by the increase in the radius of the cylinder.

We discuss photonic crystals (PhCs) with advanced micro/nano-structres which are semiconductor quantum dots (QDs) and micro electro-mechanical systems (MEMS) for the purpose of realizing novel classes of PhC devices in future photonic network system. After brief introduction on advantages to implement QDs and MEMS with PhCs, we discuss optical characterization of PhC microcavity containing self-assembled InAs QDs. Modification of emission spectrum of a QD ensemble due to the resonant cavity modes is demonstrated. We also point out the feasibility of low-threshold PhC lasers with QD active media in numerical analysis. A very low threshold current of 10 µA is numerically obtained for lasing action in the multi dimensional distributed feedback mode by using realistic material parameters. Then, the basic concept for MEMS-controlled PhC slab devices is described. We show numerical results that demonstrate some of interesting functions such as the intensity modulation and the tuning of resonant frequency of cavity mode. Finally, a preliminary experiment of MEMS-based switching operation in a PhC line-defect waveguide is demonstrated.