To evaluate heat and fire phenomena caused by accumulated microslide motion on an imperfectly connected electrical terminal, an acceleration test method using vibrator was developed. The process from the generation of CuO to that of Cu2O has been reproduced. The influence of current is investigated, and it is found that as current increases, CuO generation time T1 and Cu2O generation time T2 decrease for pure copper, however when current exceeds 3 A, we could not produce CuO or Cu2O. The contact resistances of a Cu terminal and wire, compared with the terminal material were investigated in terms of the effects of current and ambient temperature.

NEXT (Near End Crosstalk loss) and FEXT (Far End Crosstalk loss) of a high speed LAN connector are analyzed using a simple coupled line model and examined experimentally. "Crosstalk Chart" is also proposed, by which, the NEXT and FEXT can be easily read off from the mutual inductance and unbalanced capacitance between pair of lines. This approach is effective for Cat.5e [1] connectors. However, for Cat.6 [2], of which transmission bandwidth is widen to 250 MHz, some additional adjustments of path pattern on the jack and terminals PCB are required. In order to assist such the adjustments, a new simple measurement technique to grasp the complex crosstalk characteristics is proposed. Two examples are introduced. One is a conventional telephone rosette, which is enhanced to be co-usable for a Cat.5e LAN connector, where only its original circuit board is reengineered. Another is a Cat.6 connector of which PCB is modified from a conventional Cat.5e connector.

The paper presents a method for testing transport of composite contacts materials under electrical arc conditions at high currents and for polarized electrodes. Tests and the discussion of results were carried out for silver-metal, silver-metal oxide and silver-tungsten carbide contact materials. Additionally, tungsten electrode was used as the second contact which was either cathode or anode. Spectrometric analysis of arc erosion components transported onto the second electrode and into the surroundings was carried out.

The paper presents a computer program for the calculation of contact mass loss in the case of evaporation, ablation and melting. It makes use of theoretical mathematical equations previously published by a lot of researchers. For the purposes of the program, an expert system algorithm was designed. The paper presents results obtained by means of the proposed program for silver, tungsten and copper.

A movable electrode in conventional electromechanical contacts often shows a bounce against the opposite electrode during a make and break operation. Frequent bounces are troublesome. We studied this phenomenon with conventional reed switches using a slowly increasing and decreasing driving current. Judging from the measured data, Coulomb's electrostatic force cannot be neglected in efforts to suppress bounce.

The sputter erosion of arcing contacts is a very complex phenomenon, which is determined by the interaction between electromagnetic force, heat conduction and surface tension of liquid metal. A new model for evaluating the sputter erosion of electrodes is described in this paper, which is based on the electromagnetic forces against the molten pool, flowing velocity, kinetic energy and the surface tension of the molten pool. Erosion tests on AgSnO2, AgNi10 and AgNi0.15 contacts under the loads of resistance, lamp and inductance respectively at 14 VDC have been carried out. Experimental results indicate good agreement with the model's simulation. The model shows how the current and density, specific heat and other parameters of material affect the erosion rate.

The crosstalks between a single-ended line and a differential pair in parallel are analyzed using telegrapher's equations for multi-conductor lines. The crosstalk from the single-ended trace to the differential pair is estimated at shunt-arm resistors in T or Π termination networks. The analysis is conducted by incorporating the termination conditions with the solution of the telegrapher's equations. The time-domain characteristics of the crosstalk are obtained by using the fast inverse Laplace transform. The measurements are conducted easily by using a single-ended digital oscilloscope since the crosstalk is evaluated on the shunt-arm resistors. Both the calculated and measured results are presented, and the characteristics of the crosstalk are also investigated qualitatively.

The performance of M-ary code shift keying (CSK) in multipath fading channels is analyzed in this letter. In conventional spread spectrum (SS) systems, which employ a single spreading code, the interference due to the delay signal depends on the auto-correlation property of the spreading code. In CSK, since one code is selected from a code set that contains multiple codes, the effect of the delay signal differs from that for conventional SS systems. Analytical results reveal that, in the multipath fading channel, the error rate of CSK depends on the cross-correlation property with the other codes in addition to the auto-correlation of transmitted code.

Since Smart Antenna technology has powerful spatial processing ability; it is regarded as a promising approach to enhancing the data rates and capacity of wireless LAN systems. In this paper, a small size, practical switched-beam antenna system, well suited for domestic in-home networking in the 2.4 GHz band, is designed and tested. The system has the configuration of regular nine-prism, and nine 1/4 wavelength rectangular patches are symmetrically distributed on the nine sides of the prism. The switching process is based on control of the microstrip used to feed the patch radiators, by placing PIN diodes at the microstrip feeding lines. The antenna array can generate nine beams with a gain of 11 dB. All the beams generated by the system are cophasal excited and have a 40°beamwidth. Compared to the uniform array, the system can guarantee the consistency of every beam and is preferable in shape.

We propose a method of crosstalk analysis for two bent transmission lines with vias at both ends on a PCB using a circuit-concept approach in the quasi-static condition. In this condition, the electromagnetic fields can be approximately estimated by the quasi-static terms of the accurate Green's function in an inhomogeneous medium. Thus we obtain a circuit model in an ABCD matrix by taking account of the fields generated by a longitudinal line and a vertical via on a PCB. To verify the proposed approach, we conducted some experiments and compared our approach's results with measured results and a commercial electromagnetic solver's results.

We experimentally investigated terahertz photomixing operation at room temperature in an InGaP/InGaAs/ GaAs two-dimensional plasmon-resonant photomixer incorporating grating-bicoupled dual-gate structure. Photoelectrons drifting into a high-density plasmon cavity grating from an adjacent low-density one extensively excite the plasmon resonance, resulting in emission of terahertz radiation. A vertical cavity formed between the two-dimensional plasmon grating plane and an indium-tin-oxide mirror at the back surface gains the radiation. Self-oscillation initially at around 4.5 THz excited by a dc-photo carrier component was reinforced by the photomixed differential-frequency excitation at 4.0 and 5.0 THz. This indicates a possibility of injection-locked oscillation of the photomixer in the terahertz frequency band.

We propose and experimentally demonstrate a simple method for monitoring optical signal-to-noise ratio. The novel method can be used in the optical transport networks using optical cross-connects or reconfigurable optical add-drop multiplexers. OSNR is measured by monitoring the transmitted optical power and the reflected optical power from fiber Bragg grating. We have obtained OSNR with an error less than 0.8 dB.

Utilizing the small bending radius of high index contrast optical waveguides, ultra-compact optical devices such as waveguide branch, Mach-Zehnder interferometer, arrayed waveguide grating filter, microring resonator filter, and so on can be realized. We have proposed and demonstrated a vertically coupled microring resonator as an Add/Drop filter, and recently realized a hitless wavelength channel selective switch (hitless tunable Add/Drop filter) using Thermo-Optic (TO) effect of double series coupled dielectric microring resonator. Using a high-index dielectric material as the core, the response time was reduced to 105 µs (rise time) and 15 µs (fall time), which are fifteen-fold and hundred-fold faster than that of polymer material, and the reproducibility by the heat cycle test was also improved to less than 0.01 nm. The tuning range of wavelength selective switch was expanded to 13.3 nm using the Vernier effect, and a large extinction ratio of more than 20 dB was realized. In this review, the principle and recent progress of microring resonator based wavelength selective switch will be introduced and some basic switching circuits required to optical cross connect will be discussed.

This paper deals with the scattering of transverse magnetic (TM) plane wave by a perfectly conductive surface made up of a periodic array of finite number of rectangular grooves. By the modal expansion method, the total scattering cross section pc is numerically calculated for several different numbers of grooves. It is then found that, when the groove depth is less than wavelenght, the total scattering cross section pc increases linearly proportional to the corrugation width W. But an exception takes place at a low grazing angle of incidence, where pc is proportional to Wα and the exponent α is less than 1. From these facts, it is concluded that the total scattering cross section pc must diverge but pc/W the total scattering cross section per unit surface must vanish at a low grazing limit when the number of grooves goes to infinity.

Capacitive and inductive crosstalk noises are expected to be more serious in advanced technologies. However, capacitive and inductive crosstalk noises in the future have not been concurrently and sufficiently discussed quantitatively, though capacitive crosstalk noise has been intensively studied solely as a primary factor of interconnect delay variation. This paper quantitatively predicts the impact of capacitive and inductive crosstalk in prospective processes, and reveals that interconnect scaling strategies strongly affect relative dominance between capacitive and inductive coupling. Our prediction also makes the point that the interconnect resistance significantly influences both inductive coupling noise and propagation delay. We then evaluate a tradeoff between wire cross-sectional area and worst-case propagation delay focusing on inductive coupling noise, and show that an appropriate selection of wire cross-section can reduce delay uncertainty at the small sacrifice of propagation delay.

Transitions between a post-wall waveguide and a microstrip line are proposed as the key components for cost-effective millimeter-wave modules. A transition with a coaxial structure is investigated for LTCC laminated layers and 11.3% bandwidth for the reflection smaller than -15 dB is realized in 60 GHz band. The overall connector loss with 1 cm post-wall would be about 0.8 dB. The degradation due to fabrication error is also assessed. The transition in LTCC substrate fulfills electrical and manufacturing demands in millimeter-wave bands.

The utilization of a high-Tc superconductor for implementing a superconducting qubit is to be expected. Recent researches on the quantum property of Josephson junctions in high-Tc superconductors indicate that the low energy quasiparticle excitation is weak enough to observe the macroscopic quantum tunneling. Therefore, a detailed study on the quantum property of high-Tc Josephson junctions becomes more important for applications. We show our experimental results of the macroscopic tunneling of current biased intrinsic Josephson junctions in Bi-2212 and its resonant activation in the presence of microwave radiation.

Time-of-Flight Mass Spectroscopy (TOF-MS) with superconducting detectors has two advantages over MS with conventional ion detectors. First, it is coverage for a very wide range of molecule weight over 1,000,000. Secondly, kinetic energies of accelerated molecules can be measured at impact events one by one. These unique features enable an ultimate detection efficiency of 100% for intact ions and a fragmentation analysis that is critical for top-down proteomics. Superconducting MS is expected to play a role in, for example, the detection of antigen-antibody complexes, which are important for medical diagnosis. In this paper, how superconductivity contributes to MS is described.

In this paper, the authors propose a circularly polarized printed antenna combining a slot array antenna and a patch antenna, with dual-band operation. The proposed antenna has good isolation performance, is compact, and has simple configuration. This antenna is composed of two parts, a patch antenna (for Rx) on the top, and a slot array antenna (for Tx) on the bottom, respectively. The element layout is such that the lower radiation element is not hidden by the upper one for wide observation angle. Hence, both radiation elements can naturally radiate the targeted polarization. Both slot array and patch antenna are fed by electromagnetically coupled microstrip line feed. With such a configuration, it is possible to efficiently obtain good isolation characteristics for both frequency bands. Furthermore, this antenna can be easily composed and it is not necessary to use any feeding pin or via hole. The target of this antenna is mobile communications applications such as mobile satellite communications, base-station of wireless LAN, etc. Here, the design techniques are discussed and the numerical and experimental analyses are presented.

ACK thinning refers to the technique to discard or reduce TCP acknowledgements (ACKs) for the purpose of diverting scarce bandwidth to TCP data traffic. It has been shown that under some circumstances the technique is effective to boost the TCP throughput on wireless links, in particular the IEEE 802.11 wireless LAN (WLAN). In this letter, however, we show that ACK thinning backfires under congestion due to its cross-layer impact on the 802.11 MAC dynamics. With the ACK filtering example, we demonstrate the phenomenon and analyze the cause. Based on the analysis, we show how the IEEE 802.11 contention window size control solves the problem.