A novel two-dimensional (2D) beam scanning antenna array using composite right/left-handed (CRLH) leaky-wave antennas (LWAs) is proposed. The antenna array consists of a set of CRLH LWAs and a Butler matrix (BM) feeding network. The direction of the beam can be scanned two-dimensionally in one plane by changing frequency and in the other plane by switching the input ports of the BM. A four-element antenna array in the microstrip line configuration operating at 10.5 GHz is designed with the assistance of full-wave simulations based on the method of moment (MoM) and the finite-element method (FEM). The antenna array is fabricated and radiation characteristics are measured. The wide range 2D beam scanning operation with the angle from -30 deg to +25 deg in one plane by sweeping frequency from 10.25 GHz to 10.7 GHz and with four discrete angles of -46 deg, -15 deg, +10 deg, and +35 deg in the other plane by switching the input port is achieved.

A novel planar composite right/left handed (CRLH) transmission line (TL) with double-sided metal patterns, which is advantageous in high scalability and low-cost fabrication, is proposed. Fundamental characteristics of the unbalanced and balanced CRLH TLs are confirmed numerically and theoretically both by full-wave finite-element method (FEM) simulations and the equivalent circuit analysis in terms of dispersion characteristics and characteristic impedances for the periodic structure. It is also shown that the relations between the left-handed circuit parameters and the geometrical parameters of the unit cell are simple and intuitive, which is useful for designing the CRLH TL. Experiments on 10-cell unbalanced and balanced CRLH TLs are carried out and the left-handed and right-handed wave propagations are confirmed by scattering parameter and near field measurements.

A novel purely distributed two-dimensional (2D) planar structure with a negative refractive index (NRI) is proposed. The structure consists of a 2D periodic array of unit cells with metal patterns on the both sides of a substrate. The unit cell with the dimension of 55 mm2 is designed at an operation frequency of about 5 GHz by full-wave finite element method simulations. Numerical simulations on the dispersion characteristics are carried out and NRI property of the structure is confirmed. A equivalent circuit taking into account the mutual capacitance between the adjacent ports in the unit cell is introduced, and theoretical investigations based on the equivalent circuit reveals that the anisotropy can be controlled by the mutual capacitance. A 1020 unit-cell NRI material is fabricated and the NRI property has been confirmed experimentally in excellent agreement with Snell's law.

A brief review of metamaterials and their applications to antenna systems is given. Artificial magnetic conductors and electrically small radiating and scattering systems are emphasized. Single negative, double negative, and zero-index metamaterial systems are discussed as a means to manipulate their size, efficiency, bandwidth, and directivity characteristics.

A novel structure for a frequency-independent steerable composite right/left-handed (CRLH) leaky wave (LW) antenna in the millimeter-wave band is proposed. This has the advantages of wide beam scanning and low profile, and is a suitable structure for mass-production. The proposed antenna has features wherein a movable dielectric slab is placed above the CRLH LW antenna, and the radiation angle can be steered by changing the distance between the slab and the antenna using compact actuators. Moreover, slots are added to the antenna to control the aperture amplitude distribution of the array antenna in order to enhance aperture efficiency. A prototype CRLH LW antenna has been fabricated with these slots, and backward-to-forward beam scanning characteristics at 76 GHz have been demonstrated successfully by measurement. A wide scanning angle from 73 to 114 deg. has been achieved experimentally. The aperture efficiency is 25.3%.

A planar composite right/left-handed leaky wave antenna which operates at W-band is fabricated and its backward to forward beam scanning operation including broadside direction is confirmed experimentally. The scanning angle from 61 to 114 degrees with a frequency scanning range of 76 to 79 GHz is achieved.

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.

There have been significant advances in computational electromagnetics (CEM) in the last decade for a variety of antennas and propagation problems. Improvements in single frequency techniques including the finite element method (FEM), the fast mulitipole moment (FMM) method, and the method of moments (MoM) have led to significant simulation capabilities on basic computing platforms. Similar advances have occurred with time domain methods including finite difference time domain (FDTD) methods, time domain integral equation (TDIE) methods, and time domain finite element (TD-FEM) methods. Very complex radiating and scattering structures in the presence of complex materials have been modeled with many of these approaches. Many commercial products have been made available through the efforts of many individuals. The CEM simulators have enabled virtual EM test ranges that have led to dramatic improvements in our understanding of antennas and propagation in complex environments and to the realization of many of their important applications.

Artificial electromagnetic structures have significantly broadened the range of wave propagation phenomena available. In particular, it has been shown that metamaterials can be constructed for which the index-of-refraction is negative over a finite band of frequencies. In this paper, we present the design, fabrication and characterization of a metamaterial that exhibits negative refraction. The metamaterial design we explore is anisotropic in the plane of propagation. Based on our analysis and supporting simulations and measurements, we demonstrate that for the geometry considered, the anisotropic metamaterial has the identical negative refraction properties as would an isotropic negative index metamaterial.

We investigated the electrical properties of hole transport materials such as TPD, α-NPD and m-MTDATA using in-situ field effect measurement. TPD, α-NPD and m-MTDATA films showed p-type semiconducting properties, and their electrical parameters such as conductivity, carrier mobility and carrier concentration were obtained. We also examined the effect of the substrate temperature during vacuum deposition and the thermal treatment after deposition, on the electrical parameters of the films. Experimental results showed that conductivity and carrier mobility decreased as the substrate temperature increased over the glass transition temperature. These decreases in conductivity and carrier mobility as a result of thermal treatment appear to be strongly related to the degradation mechanism of organic electroluminescent devices.

A first-order investigation of the transport and energy-loss processes in silicon dioxide is worked out in the frame of the Spherical-Harmonics solution of the Boltzmann Transport Equation. The SiO2 conduction band is treated as a single-valley spherical and parabolic band. The relevant scattering mechanisms are modeled consistently: both the polar and nonpolar electron-phonon scattering mechanisms are considered. The scattering rates for each contribution are analyzed in comparison with Monte Carlo data. A number of macroscopic transport properties of electrons in SiO2 are worked out in the steady-state regime for a homogeneous bulk structure. The investigation shows a good agreement in comparison with experiments in the low-field regime and for different temperatures.

Pb(ZrxTi1-x)O3 (PZT) thin films were prepared on various electrodes. When Ir system materials were used as electrodes, fatigue properties of PZT thin films were improved. Moreover, in the case of the PZT thin film on an Ir/IrO2 electrode, not only fatigue but imprint properties were clearly improved. We could find these improvements were caused by good barrier effect of IrO2 from secondary ion mass spectroscopy (SIMS) analysis. By applying these Ir system electrodes, we fabricated stacked capacitors on polycrystalline silicon (poly-Si) plugs. In spite of high temperature thermal processing, we found poly-Si plugs were ohmically connected with the bottom electrodes of the capacitors from hysteresis measurements and I-V characteristics, and could greatly expect them for practical use.

ElectroStatic Discharge (ESD) testing of integrated circuits subjects circuit elements to very high currents for short periods of time. A modified Transmission Line Pulse (TLP) measurement system for characterizing transistors and other circuit elements under high currents for ESD performance prediction and understanding is presented which can both stress devices and measure leakage. For the TLP system to yield useful information test structures are needed which vary the important design parameters for the circuit elements. Guidelines for transistor test structure design for use with the system are presented and demonstrated for PMOS transistors.

The emphasis on nonisotropic media in the electromagnetics research community has recently brought forward a large amount of new literature on the material effects. The material phenomena affecting the electromagnetic characterization are contained in the constitutive relations between an electric and a magnetic excitation and an electric and a magnetic response. Starting from the constitutive equations, this article is an attempt to cast light on the labels, terms, notation, and classification of linear electromagnetic materials. Using dyadic analysis and physical concepts like reciprocity and magnetoelectric coupling, the different classes within bi-anisotropic media are presented in systematic form. Simple isotropic media can be characterized by two material parameters: the electric polarizability is measured by permittivity ε, and the magnetic polarizability by the permeability µ. For bi-isotropic media, there exists magnetoelectric coupling, but due to isotropy (independence of the direction of the field vectors) the two additional material parameters are scalars. The physical interpretation to these two parameters are chirality and nonreciprocity. The two subclasses of bi-isotropic materials are Pasteur and Tellegen media. If there is direction dependence in the medium, we call the material anisotropic, and a scalar quantity has to be described by a dyadic with nine components. Finally, the most general material is called bi-anisotropic, which means that in addition to a dyadic permittivity and permeability, the two magnetoelectric material parameters are dyadics. The essential feature in the classification of the present paper is the separation of all the four material parameter dyadics into symmetric and antisymmetric parts. For permittivity and permeability, the symmetric parts correspond to reciprocal media and the antisymmetric parts are nonzero for nonreciprocal media. In the cross-coupling dyadics the decomposition into symmetric and antisymmetric parts disriminates chiral media, omega media, classical magnetoelectric media, and moving media. Finally, possible alternative characterrizations of bi-anisotropic materials are discussed.

The complex refractive indices n-jχ of typical magnetic fluids were evaluated for the sake of utilizing them as optical materials. Transmission and reflection spectra were measured in the wavelength range of 0.6-1.6 µm by using monochromators. Magnetic fluids were put into glass cells of 2.5-14-µm thickness for transmission measurement. Due to the absorption by magnetic fluids, the transmittance decreased notably with the increase of the sample thickness. The extinction coefficient χ was evaluated from the dependence of the transmittance on the sample thickness. χ was found to vary between 0.003 and 0.03 depending upon wavelength. The refractive index n was evaluated by fitting theoretical curves to the reflectances that were measured for various incident angles. n was found to vary between 1.6 and 1.7 depending slightly on wavelength. Since a magnetic fluid is a composite of ferrite particles and a solvent, the refractive index can be calculated by using the effective medium theory. The calculated value agreed well with the experimental value. Preliminary experiment of optical switching was also demonstrated by utilizing the mobility of a magnetic fluid.

A full confocal Gaussian beam open resonator system that determines the dielectric properties of low-loss materials in the 60-GHz band is developed. To achieve high Q values a quasi-optical coupling method is used to feed the resonator. It is connected to a computer-controlled HP 8510C vector network analyzer for automatic measurement. The frequency variation method is used and the data are processed using the open resonator scalar theory. Results from 96% and 99.5% alumina samples with thicknesses ranging from 0.38 mm to 1 mm, are presented in the V band, with loss tangent values of the order of 100 µ radians. This system should be able to measure substrates as thin as less than 0.1 mm to 0.3 mm, which are the thicknesses of substrates in practical use.

A low contact resistivity of 4.410-7 Ωcm2 for AlGaAs/GaAs HBTs was realized using Pt/Ti/Pt/Au base metal and a 81019 cm-3 highly-doped base. A high fmax of 170 GHz was achieved by reducing a base resistance. The formation of oxide-free interface between an AlGaAs graded base and Pt-based metal was demonstrated with Auger electron spectroscopy. The optimization of the growth condition conquered the rapid current-induced degradation in the highly Be-doped HBTs. An extremely wide bandwidth of 40 GHz was attained by a Darlington feeback amplifier fabricated using these high-fmax HBTs. These properties indicate that the application of AlGaAs/GaAs HBTs can be expected to extend to future ultrahigh-speed optical transmission systems.

The authors have studied mechanism of transition from metallic phase to gaseous phase in contact break arc. For further elucidation of the mechanism, we have carried out spectroscopic measurement. The spectrum measurement system which had high time resolution was composed using two monochromators and a bifurcated image fiber, which had one input port and two output ports. The input port received the arc light, and the two monochromators received the arc light from the two output ports, respectively. The spectral sensitivity of the two monochromators was corrected with a standard lamp. We have measured simultaneously two spectra of break arc for Ag in laboratory air, under the condition where source voltage E=48 V, load inductance L=2.3 mH, and closed contact current I0=6 A. As a result, the time-varying tendency of spectrum intensity is similar for the same element, even if the wavelength is different. And from the comparison of time average spectrum intensity, it is clarified that average intensity for gas spectrum does not attain to 10% of that for metallic atomic spectrum (Ag I, 520.91 nm). In addition, the decrease point of Ag II (ion) spectrum has been found to correspond with the peak of Ag I (atom) spectrum.

In this paper, the relationship between contact materials and sticking characteristics, and stability of contact resistance to obtain excellent contacts for telecommunication relays, is studied. The contact switching current for telecommunication relay is low. Moreover, contact force and opening force in these relay are respectively several mN. Nine kinds of contact materials are selected as a experimental factor. They are Ag, Ag-Ni (Ni: 0.03 to 20%), Ag-Cu 10%, Ag-Pd 60% and Pd-Ru 10%, and are overlaid with gold except Pd-Ru 10%. In this study, contact life tests on a commercial ultra-miniature telecommunication relay by mounting above-mentioned contacts are conducted. The sticking and the contact resistance are monitored at each switching operation in the contact life test. After the life test, the contact surfaces are observed, and the depth of crater, the height of pip and projected concave area are measured, then the relationship between the sticking morphologies and the composition of each material are studied. As the result of this study, the contact sticking of telecommunication rely is assumed to be the result of mechanical locking, and the effects of the Ni content in the Ag-Ni contacts is clarified. Moreover, it is confirmed that the effects of opening force on the sticking characteristics are remarkable.

Reliability of an electric contact can be defined by two parameters, contact resistance and wear, and the parameters of contacts operated in arcing condition are governed by the arc discharge. Thus the measurement on the relationship between the parameters and arc phenomena is necessary to improve the contact performance. The parameters for arcing electric contacts and problems were reviewed, and new concept for electric contact testing systems was proposed. Measurement with such an advanced system should be concurrent parallel measurement, quantitative measurement of degradation, systematic measurement, and analysis of arc discharge phenomena. Some examples of advanced measurement systems and new data obtained with such systems were described. Systematic results on relationships between condition and performance parameters were obtained by systematic measurement with systematically settled conditions, such as opening speed or material condition. A measurement method for the metallic phase arc duration was developed by the authors, and role of the metallic phase arc on contact performance parameters was found from interpretation of obtained data. The real-time surface profile measurement of an operating contact and the optical transient spectrum analyser for arc light radiated from breaking contact were also described.