Hang Liu Fei Wu
Keiji GOTO Toru KAWANO Ryohei NAKAMURA
Takahiro SASAKI Yukihiro KAMIYA
Xiang XIONG Wen LI Xiaohua TAN Yusheng HU
Anton WIDARTA
Hiroshi OKADA Mao FUKINAKA Yoshiki AKIRA
Shun-ichiro Ohmi
Tohgo HOSODA Kazuyuki SAITO
Shohei Matsuhara Kazuyuki Saito Tomoyuki Tajima Aditya Rakhmadi Yoshiki Watanabe Nobuyoshi Takeshita
Koji Abe Mikiya Kuzutani Satoki Furuya Jose A. Piedra-Lorenzana Takeshi Hizawa Yasuhiko Ishikawa
Yihan ZHU Takashi OHSAWA
Shengbao YU Fanze MENG Yihan SHEN Yuzhu HAO Haigen ZHOU
Ryo KUMAGAI Ryosuke SUGA Tomoki UWANO
Jun SONODA Kazusa NAKAMICHI
Kaiji Owaki Yusuke Kanda Hideaki Kimura
Takuya FUJIMOTO
Yuji Wada
Fuyuki Kihara Chihiro Matsui Ken Takeuchi
Keito YUASA Michihiro IDE Sena KATO Kenichi OKADA Atsushi SHIRANE
Tomoo Ushio Yuuki Wada Syo Yoshida
Futoshi KUROKI
Jun FURUTA Shotaro SUGITANI Ryuichi NAKAJIMA Takafumi ITO Kazutoshi KOBAYASHI
Yuya Ichikawa Ayumu Yamada Naoko Misawa Chihiro Matsui Ken Takeuchi
Ayumu Yamada Zhiyuan Huang Naoko Misawa Chihiro Matsui Ken Takeuchi
Yoshinori ITOTAGAWA Koma ATSUMI Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Zhibo CAO Pengfei HAN Hongming LYU
Takuya SAKAMOTO Itsuki IWATA Toshiki MINAMI Takuya MATSUMOTO
Koji YAMANAKA Kazuhiro IYOMASA Takumi SUGITANI Eigo KUWATA Shintaro SHINJO
Minoru MIZUTANI Takashi OHIRA
Katsumi KAWAI Naoki SHINOHARA Tomohiko MITANI
Baku TAKAHARA Tomohiko MITANI Naoki SHINOHARA
Akihiko ISHIWATA Yasumasa NAKA Masaya TAMURA
Atsushi Fukuda Hiroto Yamamoto Junya Matsudaira Sumire Aoki Yasunori Suzuki
Ting DING Jiandong ZHU Jing YANG Xingmeng JIANG Chengcheng LIU
Fan Liu Zhewang Ma Masataka Ohira Dongchun Qiao Guosheng Pu Masaru Ichikawa
Ludovico MINATI
Minoru Fujishima
Hyunuk AHN Akito IGUCHI Keita MORIMOTO Yasuhide TSUJI
Kensei ITAYA Ryosuke OZAKI Tsuneki YAMASAKI
Akira KAWAHARA Jun SHIBAYAMA Kazuhiro FUJITA Junji YAMAUCHI Hisamatsu NAKANO
Seiya Kishimoto Ryoya Ogino Kenta Arase Shinichiro Ohnuki
Yasuo OHTERA
Tomohiro Kumaki Akihiko Hirata Tubasa Saijo Yuma Kawamoto Tadao Nagatsuma Osamu Kagaya
Haonan CHEN Akito IGUCHI Yasuhide TSUJI
Keiji GOTO Toru KAWANO Munetoshi IWAKIRI Tsubasa KAWAKAMI Kazuki NAKAZAWA
Norimasa NAKASHIMA Mitsuo TATEIBA
The boundary element method (BEM), a representative method of numerical calculation of electromagnetic wave scattering, has been used for solving boundary integral equations. Using BEM, however, we finally have to solve a linear system of L equations expressed by dense coefficient matrix. The floating-point operation is O(L2) due to a matrix-vector product in iterative process. Greengard-Rokhlin's fast multipole algorithm (GRFMA) can reduce the operation to O(L). In this paper, we describe GRFMA and its floating-point operation theoretically. Moreover, we apply the fast Fourier transform to the calculation processes of GRFMA. In numerical examples, we show the experimental results for the computation time, the amount of used memory and the relative error of matrix-vector product expedited by GRFMA. We also discuss the convergence and the relative error of solution obtained by the BEM with GRFMA.
Dao Ngoc CHIEN Kazuo TANAKA Masahiro TANAKA
We show examples of accurate computer-aided design of power coupling between two dielectric slab waveguides of finite length by using the boundary-element method (BEM) based on guided-mode extracted integral equations (GMEIE's). The integral equations derived in this paper can be solved by the conventional BEM. Various properties in numerical calculations of GMEIE's are examined. The reflection and coupling coefficients of the guided wave as well as the scattering power are calculated numerically for the case of incidence TM guided-mode. The presented results are checked by the energy conservation law and reciprocity theorem. The results show that it is possible to design an optimum coupling between two dielectric slab waveguides by using the BEM based on GMEIE's.
Michinari SHIMODA Ryuichi IWAKI Masazumi MIYOSHI Oleg A. TRETYAKOV
The transient phenomenon of electromagnetic waves caused by a time dependent resistive screen in a waveguide is treated. A boundary-value problem is formulated to describe the phenomena, in which the resistivity of the screen varies from one steady state to another in dependence on time. Application of Fourier analysis derives an integral equation, which is approximately solved by the method of least-squares. From the solution of the equation, the transient field is obtained by the inverse Fourier transform. By the use of the incomplete Lipschitz-Hankel integral for the computation of the field, numerical examples showing typical transient phenomenon are attached.
Takeshi SHIRAISHI Toshio NISHIKAWA Kikuo WAKINO Toshihide KITAZAWA
A novel hybrid numerical method, which is based on the extended spectral domain approach combined with the mode-matching method, is applied to evaluate the scattering parameter of waveguide discontinuities. The formulation procedure utilizes the biorthogonal relation in the transformation, and the Green's functions in the spectral domain are obtained easily even in the inhomogeneous lossy regions. The present method does not include the approximate perturbational scheme, and it can evaluate accurately and stably the scattering parameters of either for the thin or thick obstacles made of the wide variety of materials, the lossless dielectrics to highly conductive media, in short computation time. The physical phenomena of transmission through the lossy obstacles are investigated by numerical computations. The results are compared with FEM where FEM computations are feasible, although the FEM computations cannot cover the whole performances of the present method. The good agreement is observed in the corresponding range. The matrix size in this method is smaller than that of other methods. Therefore, the present method is numerically efficient and it would be able to apply for the integrated evaluation of a successive discontinuity. The resonant characteristics of rectangular waveguide cavity are analyzed accurately taking the conductor losses into consideration.
Koichi HIRAYAMA Naoto KUNIEDA Yoshio HAYASHI Masanori KOSHIBA
Making up an electromagnetic wave simulator based on the FEM is tried, which may run on some widely used platforms by use of Java and a single commercial tool. Since the codes and configuration files to be created for this simulator are common, one can construct the simulator running on the platforms at the same time. Using this simulator, the transmission properties of two- and three-dimensional waveguide discontinuities in optical and microwave waveguides are analyzed, the inverse problem in material constant measurement is solved, and the computed results are presented including plots of the electric field distribution.
Shun-suke MATSUOKA Katsunori OHMI Hideki KAWAGUCHI
For High Performance Computing (HPC) of electromagnetic microwave simulations, the authors present concept for a microwave simulation dedicated computer, FDTD/FIT data flow machine. By constructing a dedicated computer customized to the data flow of the FDTD or FIT scheme, we can obtain maximum performance from the FDTD/FIT simulations and achieve T FLOPS performance computing by using much smaller size computer system than conventional supercomputers. In addition to the basic idea, this paper identifies with solution to some other factors which are needed to execute practical simulations (e.g., boundary condition setting, power input, simulation result data upload to PC, etc.). Moreover, the VHDL design and logical simulation of the 2D data flow machine are also shown as the first step of development of the FDTD/FIT data flow machine.
Shogo HAYASHIDA Hisashi MORISHITA Kaoru HIRASAWA Tomoki TANAKA
As the capacity of a personal computer and workstation increases rapidly, many electromagnetic simulators solving antenna problems are widely used. In this paper, the IE3D, FIDELITY and HFSS electromagnetic simulators, which are commercial software products, are applied to the analysis of built-in antennas for handsets in the vicinity of the human body. The IE3D, FIDELITY and HFSS electromagnetic simulators are based on the methods of moment, FDTD (Finite Difference Time Domain) and FEM (Finite Element Method), respectively. Firstly, basic characteristics including the human body's effect of a popular built-in antenna for handset such as PIFA (Planar Inverted-F Antenna) are obtained by the IE3D, FIDELITY and HFSS electromagnetic simulators, and calculated results are compared with measured results. Secondly, on the basis of newly considered design concepts for a handset antenna, a folded loop antenna for handset, which we have proposed in order to reduce the influence of the human body, is taken as an example of a balance-fed antenna and is analyzed theoretically and experimentally including the influence of the human body. In a result, calculated results by these three kinds of electromagnetic simulators are in good agreement with measured results and it is confirmed that these simulators are very effective in analyzing the handset antenna in the vicinity of the human body.
Electromagnetic shielding clothes for reducing human exposure to radio waves have been commercialized. However, their effect has so far been confirmed only in the form of the raw material. In this paper, we develop a new compact scheme for measuring electromagnetic radiations using a short dipole antenna and Gaussian pulses in order to evaluate the effect of the shielding clothes over a wide frequency range with the aid of time-domain measurements and FDTD computation. The proposed method is based on a time-domain analysis technique and pulse compression technique, which enables the user to separate the direct transmission wave from the reflection from the floor as well as from the refracted wave around the neck of the clothes. The direct advantage is that measurements can be made in an ordinary laboratory without the function of an electromagnetic anechoic chamber. Also, we can separate direct transmission wave and diffraction wave from the measurement result by using pulse compression technique, then each frequency characteristic of the shielding shirt can be evaluated. The performance of the separation is confirmed by comparing the measurements with those of a shirt with no opening. We further demonstrate the possibility of predicting the effective conductivity of the material as a function of frequency by comparing the measured results with realistic FDTD computations, which will enable us to design a shielding shirt via numerical means.
Hidenori SEKIGUCHI Hiroshi SHIRAI
A simple non-destructive depth estimation method for a crack on a metal surface has been proposed. This method is based on our finding that the electromagnetic back scattering from a narrow trough (crack model) on the ground plane causes periodical nulls (dips) as the frequency changes, and the first dip occurs when the depth of the crack becomes nearly one half of the incident wavelength. Dependencies of the crack's aperture and the incident angle have also been studied from rigorous and numerical analyses, and considered as our depth estimation parameters. A simple estimation formula for a crack depth has been derived from these studies. Test measurement has been made to check the accuracy of our estimation formula. Time domain gating process is utilized for isolating the crack scattering spectra buried in the measured frequency RCS data. Tested crack types are a narrow rectangular, a tapered, and a stair approximated crack shapes. It is found that the depth of these cracks can be measured within 3 percent error by our estimation method.
Chun Jen LIN Chien-Ching CHIU Yi-Da WU
In this paper, an efficient optimization algorithm for solving the inverse problem of a two-dimensional lossless homogeneous dielectric object is investigated. A lossless homogeneous dielectric cylinder of unknown permittivity scatters the incident wave in free space and the scattered fields are recorded. Based on the boundary condition and the incident field, a set of nonlinear surface integral equation is derived. The imaging problem is reformulated into optimization problem and the steady-state genetic algorithm is employed to reconstruct the shape and the dielectric constant of the object. Numerical results show that the permittivity of the cylinders can be successfully reconstructed even when the permittivity is fairly large. The effect of random noise on imaging reconstruction is also investigated.
Genetic algorithm (GA) is a widely used numerical technique to simplify some analytical solutions in electromagnetic theory. Genetic algorithms can be combined with the geometric optics method to tackle electromagnetic scattering problems. This paper presents an extrapolation procedure, which derived, as a first step, a functional representation of the radar cross section (RCS) of three different dielectric objects that was computed via the Mie solution or the method of moments (MOM). An algorithm was employed to fit the scattering characteristics of dielectric objects at high frequencies.
We developed a process to fabricate optical functions such as, lens, prism, or diffuser directly on to a glass substrate. Processes include precision mastering by diamond cutting, and multi-layer photopolymer (2P) molding process to realize flat surface and integration of multiple functions with a good alignment within few micrometers.
Changhun LEE Haksun CHANG Seonhong AHN Kunjong LEE
We have obtained high performance and low voltage driving OCB panel by reducing the critical voltage and retardation matching between liquid crystal layer and compensation films. Flattening color filter layer and optimizing rubbing process have minimized the critical voltage in the panel. In addition, an appropriate retardation of the film and LC layer has scanned to achieve low driving voltage and high transmission. Especially, by adopting new driving scheme, we considerably reduced the initial bend transition time, which is known as one of drawbacks in OCB mode. As a result, we developed the proto-type 17" WXGA OCB panel with less than 5 V drive, over 90% of TN light efficiency and over 80 degree for all viewing direction except for rubbing direction including color shift as well as high-speed response time.
Toshiaki ONIMARU Shin'ya FUKUTA Tomonari MISAWA Koichi SAKITA Keiichi BETSUI
We investigated the intercalation of water into BaMgAl10O17:Eu2+ (BAM), a blue phosphor that is used in plasma display panels. The adsorption and desorption characteristics of water with BAM have hysteresis; showing that water is intercalated into BAM. Using thermal analysis techniques, we suggested that water hydrated to barium ions caused oxidation. We found that the water intercalated into BAM played an important role in the oxidation of Eu2+ between 450
Tetsuya SHIROISHI Shuhei NAKATA Nobuhide HINOMOTO Katsumi OONO Fumiaki MURAKAMI Soichiro OKUDA
We've been developing new electron guns for a high brightness CRT. The electron guns were modified to increase the emission current without the increase of the driving voltage. We achieved the high brightness CRT with "low cut-off electron gun" and the gun was successfully introduced into our multimedia CRT. Now we are developing next generation gun or "double drive electron gun" for larger screen CRT. The gun can emit about double current in comparison with the "low cut-off electron gun."
A.A. Seyno SLUYTERMAN Tjerk G. SPANJER
The size of the microscopic electron spot is an important parameter for the white-uniformity of a CRT. It changes as a function of the focus voltage and beam repulsion. This paper explains the mechanism behind this phenomenon. The model is supported by means of measurements.
Makoto SHIBUSAWA Michiya KOBAYASHI Jun HANARI Kazuyuki SUNOHARA Nobuki IBARAKI
We have developed a 17-inch WXGA full-color polymer OLED display by using newly developed ink-jet printing method. On the ink-jet technology, both droplet volume and landing position were precisely controlled pixel by pixel in order to get luminance uniformity. A pixel circuit having Vth variation-cancellation was adopted and the circuit was modified to realize high uniformity and high gray scale reproduction under the short horizontal period operation. Correction on gamma profile difference among RGB OLEDs was achieved by optimizing on configuration between integrated source driver circuit and outer reference voltage circuit in spite of using a common source driver IC having only one gamma profile. Peak control system, that is important for the large size and high luminance display, was utilized and improved image quality on human feeling and actual power consumption. With these efforts a uniform picture with 260,000 colors and wide viewing angle was achieved. It was proved that the ink-jet method was the optimal manufacturing technology for large-size and high-resolution OLED displays. And we found there is no singular problem on the large size OLED display utilized the ink-jet technology.
Masayuki JYUMONJI Yoshinobu KIMURA Masato HIRAMATSU Yukio TANIGUCHI Masakiyo MATSUMURA
A two-dimensional laser beam profiler has been developed that can measure the intensity distribution on a sample surface of a single-shot of an excimer-laser light beam from not only the macroscopic viewpoint, but also the microscopic viewpoint, which is important to excimer-laser triggered lateral large-grain growth of Si. A resolution as fine as 0.4 µm was obtained with a field of view of as large as 30 µm
Koichi IIYAMA Junya ASHIDA Akira TAKEMOTO Saburo TAKAMIYA
One-dimentional equivalent circuit model of a heterostructure InAlAs/InGaAs/InP metal-semiconductor-metal photodetector is discussed. In this photodetector, InGaAs is used as an optical absorption layer and the InAlAs is used for Schottky barrier enhanement. The measured S11 parameter deviates from equi-resistance lines on the Smith chart, indicating the equivalent circuit is different from the conventional equivalent circuit using a series resistance, a depletion region capacitance and a depletion region resistance. The difference is due to band discontinuity at the heterojunctions, and we propose a equivalent circuit taking account of the band discontinuity. The band discontinuity is expressed by parallel combination of a resistance and a capacitance. The measured S11 parameter can be fitted well with the calculated S11 parameter from the proposed equivalent circuit, and we can successfully extract the device parameters from the fitted curve.
Akira ENOKIHARA Hideki NANBA Toshiaki NAKAMURA Kojiro OKUYAMA Toshio ISHIZAKI Tomoki UWANO
26 GHz bandpass filter and duplexer using TM11δ rectangular-mode dielectric cavity resonators are proposed. These have a configuration compact and suitable for mounting on circuit boards. The resonators consisting of the Ba(Mg,Ta)O3 ceramic material showed a high quality factor value of 2600, which is roughly comparable to that of conventional E-plane waveguide filters. The dielectric losses of the ceramic material were experimentally evaluated from the viewpoint of the high frequency operation and the dielectric loss tangent of 7.4
Field-theoretical equivalent circuit models of a variety of coplanar waveguide (CPW) lumped-element discontinuities for two dominant modes are characterized by executing the short-open calibration (SOC) procedure in the fullwave method of moments (MoM). In our developed MoM platform, the impressed current sources with even or odd symmetry are introduced at the selected ports in order to separately excite the even and odd dominant modes, i.e., CPW- and CSL-mode. After the port network parameters are numerically derived using the Galerkin's technique, the two SOC standards are defined and evaluated in the self-consistent MoM to effectively de-embed and extract the core model parameters of a CPW circuit or discontinuity. After the validation is confirmed via comparison with the published data, extensive investigation is carried out to for the first time demonstrate the distinctive model properties of one-port CPW short- and open-end elements as well as two-port inductive and capacitive coupling elements with resorting to its two different dominant modes.
In this paper, a novel technique using proportional current feedback is proposed to improve dynamic response of digital PWM DC-DC converters. Generally, digital controllers are implemented using microprocessors or DSPs. Additional A/D converters are required to sense feedback signals. Proposed simple structure makes it feasible to integrate both A/D converter and digital controller on a single chip. System complexity and hardware cost are therefore greatly reduced. A behavioral time domain circuit model is proposed and analyzed using MATLAB. Both simulation and experimental results showed satisfactory performance to meet power requirements of microprocessors.
Franco FIORI Paolo S. CROVETTI
In this paper a second order Volterra series model of an operational amplifier (opamp) circuit is presented. Such a model is suitable to the investigation of the rectification and demodulation effects of radio frequency (RF) interference superimposed on the nominal input signals and on the power supply voltage of an opamp. On the basis of the new model, some design criteria to improve the immunity of opamps to RF interference are proposed. Model predictions are verified by comparison with experimental test results.
Yusuke OIKE Makoto IKEDA Kunihiro ASADA
A high-speed 3-D camera has a future possibility of wide variety of application fields such as quick inspection of industrial components, observation of motion/destruction of a target object, and fast collision prevention. In this paper, a row-parallel position detector for a high-speed 3-D camera based on a light-section method is presented. In our row-parallel search method, the positions of activated pixels are quickly detected by a row-parallel search circuit in pixel and a row-parallel address acquisition of O(log N) cycles in N-pixel horizontal resolution. The architecture keeps high-speed position detection in high pixel resolution. We have designed and fabricated the prototype position sensor with a 128
Rabindranath NANDI Arijit GOSWAMI Rajendra K. NAGARIA Salil K. SANYAL
Some new differential input ideal differentiator and integrator function circuits using the current feedback amplifier (CFA) device are presented. The time constant (τo) is tunable by the control voltage (Vc) of a multiplier element connected appropriately around the feedback loop. The CFA device port errors (
Atsushi NOYA Mayumi B. TAKEYAMA
A high temperature performance of a W2N compound barrier in the model electrode configuration of W/W2N/poly-Si was examined. The stacked electrode was fairly stable upon annealing at 850
This paper proposes a 10 µm thick oxide layer structure, which can be used as a substrate for RF circuits. The structure has been fabricated by anodic reaction and complex oxidation, which is a combined process of low temperature thermal oxidation (500
This paper describes the robust design of the 30 V high voltage NMOS (HVNMOS) structure implemented in a 0.6 µm 5 V standard CMOS processes without any additional masks or process steps. The structure makes use of the field oxide (FOX) and light doping N-well to increase the drain to gate and drain to bulk breakdown voltages, respectively. By varying the six spacing parameters: the channel length, gate overlap FOX, N-well overlap channel length, poly to the active area of the drain (OD2), metal extend beyond the OD2 and N-well extend beyond the OD2 in HVNMOS structure, the breakdown voltage can be improved. The experimental results show that the breakdown voltage of the normal NMOS is 11 V, and the breakdown voltage of the HVNMOS is increased to over 30 V. With the optimized layout parameters of the HVNMOS, it can be increased to 38 V.
Sangyun HWANG Gunhee HAN Sungho KANG Jaeseok KIM
This paper presents a low-power implementation scheme of interpolation FIR filters using distributed arithmetic (DA). The key idea of the proposed scheme involves look-up tables generating only nonnegative values. Thus, the proposed scheme can minimize the dynamic power consumption of interpolation FIR filters using DA without additional hardware. When used for implementing a pulse shaping filter for CDMA2000 mobile stations, the proposed filter not only has almost the same hardware complexity as the conventional one; it also has approximately 43% reduced power consumption.