Faculty Profiles - TOYOTA Yoshitaka

MISC - TOYOTA Yoshitaka

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Investigation of Parasitic Capacitance to Improve EMC Macro Model LECCS around 1GHz

TAKAHASHI A., IOKIBE K., PAOLETTI U., WADA O., TOYOTA Y., KOGA R.

IEICE technical report 107 ( 167 ) 5 - 10 2007.7

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

High frequency currents flowing in power supply networks of an IC/LSI has been estimated by an EMC macro model. The high frequency currents due to the simultaneous switching noise of IC/LSI involving large amount of CMOS transistor is modeled with a linear equivalent circuit and current sources. The linear equivalent circuit decreased its accuracy in impedance due to parasitic capacitances causing anti-resonances in the power supply networks. This paper shows with results of experimental and numerical analysis that the parasitic capacitances on the package and printed circuit board cause the anti-resonance. The power supply network impedance were obtained experimentally by use of three evaluation boards with different parasitic capacitances. The parasitic capacitances of the boards were calculated numerically by high-frequency electromagnetic analysis software Sonnet. Impedance simulations by considering the parasitic capacitance shows that an appropriate connection of parasitic capacitances to the LECCS model can expand an available frequency range of the model beyond 1 GHz.

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Estimation of Radiated Emissions with Common-mode Antenna Model of Printed Circuit Board : Superposition of Common-mode Excitation Sources

FUKUMASU Keisuke, WATANABE Tetsushi, TOYOTA Yoshitaka, IOKIBE Kengo, KOGA Ryuji, WADA Osami

IEICE technical report 107 ( 107 ) 39 - 44 2007.6

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

A common-mode antenna model proposed by the authors is able to predict common-mode radiation from printed circuit boards (PCBs). The model consists of a common-mode excitation source and segmented antenna elements. This repeat discusses the superposition of common-mode sources, the superposition helps to calculate the radiated emissions due to the common-mode excitation in a PCB containing several MSLs. For the evalution, several PCBs with a MSL bent at a right angle were designed and fabricated. Through the experiments and numerical simulation with FDTD method, it was found that the superposition of excitation sources is available to build the common-mode antenna model.

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Estimation of Electromagnetic-emission from PCBs with a Connector through the Common-mode Antenna Model

SADATOSHI Akifumi, SAKAI Youhei, WATANABE Tetsushi, TOYOTA Yoshitaka, IOKIBE Kengo, KOGA Ryuji, WADA Osami

IEICE technical report 107 ( 25 ) 49 - 54 2007.4

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

The amount of radiated emission from the connector between the motherboard and the daughterboard depends on the number of ground pins. This paper discusses the prediction of the amount of radiated emission from printed circuit boards with a connector using the common-mode antenna model proposed by the authors. the effect of reflection of an unmatched interface such as the connector-board was taken into account by using the measurement result of normal mode voltage in simulation. Common-mode emission is reduced by decreasing imbalance between the conn ector and the board.

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B-4-42 Miniaturization and Stopband Expansion of EBG Structure Formed in Power/Ground Plane Pair of PCBs Using High Permeability Materials

Toyota Yoshitaka, Iokibe Kengo, Koga Ryuji

Proceedings of the IEICE General Conference 2007 ( 1 ) 366 - 366 2007.3

Common-mode current related to cable ground in shape

MORIMITSU Kazuya, WATANABE Tetsushi, TOYOTA Yoshitaka, KOGA Ryuji, WADA Osami

IEICE technical report 106 ( 579 ) 71 - 75 2007.3

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

Common-mode current was measured for a four-conductor system that is electrically floating above the reference ground. A parallel cable is used to connect a imtative common-mode transmitter and a receiver. Common-mode current was measured for different height of the devices above the ground as well as the length of the cable. The transmitter was driven with an optical fiber in order to isolate the devices from the ambient electromagnetic field. Experimental results showed that the current was almost constant for the height over 10cm, and for the lower it was increased with decreasing the height from the reference ground due to the effect of the ground. The effect of the number of ground cables was examined and it was confirmed that the common-mode current along the cable decreases with the number of ground cables in the parallel cable. The trend is explained by the relationship of common-mode current with the difference of the current divison factor between devices and the cables.

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Common-mode current related to cable ground in shape

ITE technical report 31 ( 17 ) 71 - 75 2007.3

Prediction of electromagnetic emissions from PCBs with interconnections through common-mode antenna model

Yoshitaka Toyota, Akifumi Sadatoshi, Tetsushi Watanabe, Kengo Iokibe, Ryuji Koga, Osami Wada

EMC ZURICH-MUNICH 2007, SYMPOSIUM DIGEST 107 - + 2007

Language：English Publisher：ETH FOUNDATION ZURICH

A motherboard-daughterboard structure with a connector is known to have another source of common-mode radiated emissions, and the emissions depend on the connector's signal/ground pin configuration. In order to estimate the amount of radiated emissions from the structure, a common-mode antenna model is described. The model consists of an excitation source and an antenna element, and it calculates radiated emissions from PCBs not only quickly but accurately for practical use. In modeling the board interconnection via a connector, we added two common-mode excitation sources at each end of the connector. The electromagnetic emissions estimated by the model agreed with the measurements within an error of 6 dB around peak emission levels between 300 and 600 MHz.

DOI： 10.1109/EMCZUR.2007.4388207

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Prediction of common-mode radiation from printed circuit boards with interconnections

Yoshitaka Toyota, Akifumi Sadatoshi, Tetsushi Watanabe, Kengo Iokibe, Ryuji Koga, Osami Wada

2007 4TH INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY PROCEEDING: EMC 2007 142 - + 2007

Language：English Publisher：IEEE

In order to estimate. the amount of common-mode radiation from a printed circuit board with low calculation cost, a common-mode antenna model has been developed. This paper demonstrates the application of the model to a board interconnection via a connector that is known to be a possible source of common-mode radiation. The radiated emissions estimated by the model agreed with the measurements for practical use.

DOI： 10.1109/ELMAGC.2007.4413451

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Miniaturization of electromagnetic bandgap (EBG) structures with high-permeability magnetic metal sheet

Yoshitaka Toyota, Kengo Iokibe, Ryuji Koga, Arif Ege Engin, Tae Hong Kim, Madhavan Swaminathan

2007 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY: WORKSHOP AND TUTORIAL NOTES, VOLS 1-3 55 - + 2007

Language：English Publisher：IEEE

Electromagnetic bandgap (EBG) structures in a pair of parallel planes are quite effective for suppressing simultaneous switching noise, but they are too large to be applied to compact electronic devices. To miniaturize the EBG structures, we investigated an approach to interpose a high-permeability magnetic metal sheet between the parallel planes. The experimental results show that high permeability of the sheet shifts the stopband towards lower frequencies. This suggests that such sheets contribute to the miniaturization of the EBG structures. In addition, it is demonstrated that the imaginary part of the permeability can expand the stopband.

DOI： 10.1109/ISEMC.2007.19

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Fast and accurate estimation of radiated emission from printed circuit board using common-mode antenna model based on common-mode potential distribution

Yoshitaka Toyota, Youhei Sakai, Makoto Torigoe, Ryuji Koga, Tetsushi Watanabe, Osami Wada

2007 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY: WORKSHOP AND TUTORIAL NOTES, VOLS 1-3 702 - + 2007

Language：English Publisher：IEEE

The authors investigated common-mode potential distribution on printed circuit boards and propose a common-mode antenna model that consists of a common-mode excitation source and a common-mode antenna element. The antenna model is able to predict common-mode radiation from PCBs quickly and accurately because it focuses only on common-mode radiated emissions. This paper applies the model to a rectangular printed circuit board with a signal trace bent at a right angle and discusses the superposition of common-mode excitation sources that result from common-mode potential distribution. In the model, the trace is divided into two straight elements at the corner to obtain the common-mode excitation source separately for each straight element. Superposing each source at each position enables a set of common-mode sources of the entire common-mode antenna model to be obtained. Simulations and measurements showed that the superposition of common-mode sources accurately predicts radiated emissions.

DOI： 10.1109/ISEMC.2007.138

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コモンモード電位分布に基づくプリント回路基板の等価アンテナモデル

酒井陽平, 渡辺哲史, 豊田啓孝, 古賀隆治, 和田

電子情報通信学会論文誌 B J90-B ( 11 ) 1116 - 1123 2007

Determination of Effective Parasitic Capacitance around IC Package for EMC modeling

Kengo Iokibe, Atsuhiro Takahashi, Umberto Paoletti, Osami Wada, Yoshitaka Toyota, Ryuji Koga

Proceedings of 6th International Workshop on Electromagnetic Compatibility of Integrated Circuits (EMC Compo 2007) 31 - 34 2007

Fast calculation of radiated emissions from arbitrarily shaped PCB with IC/LSI

Masahiro Nishida, Yoshitaka Toyota, Kengo Iokibe, Ryuji Koga, Osami Wada

2007 4TH INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY PROCEEDING: EMC 2007 255 - + 2007

Language：English Publisher：IEEE

This paper describes fast calculation of radiated emissions from an arbitrarily shaped printed circuit board (PCB). The radiated emissions from the PCB edge are calculated by taking into account magnetic surface current based on the field equivalent principle. The electric field at the PCB edge is provided by a fast algorithm the authors have proposed for power-bus resonance in the PCB. The calculation of radiated emission was completed within a few minutes and in, good agreement with Finite Difference Time Domain (FDTD) calculation. In addition, an EMI simulation was demonstrated by using a linear macro model of IC/LSI. The calculation results were found to be in good agreement with the measurements.

DOI： 10.1109/ELMAGC.2007.4413479

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プリント回路基板の電源/グランドプレーンに形成する不要電磁波伝搬抑制のためのプレーナEBG構造の小型化

豊田啓孝, エンゲンアリフエゲ, スワミナッサンマダハバン, 五百旗頭, 健, 古賀隆治

電子情報通信学会論文誌 B J90-B ( 11 ) 1135 - 1142 2007

Stopband analysis using dispersion diagram for two-dimensional electromagnetic bandgap structures in printed circuit boards

Yoshitaka Toyota, Arif Ege Engin, Tae Hong Kim, Madhavan Swaminathan

IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS 16 ( 12 ) 645 - 647 2006.12

Language：English Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Electromagnetic bandgap (EBG) structures that provide an excellent isolation within the stopband are extremely effective in suppressing propagation of simultaneous switching noise on parallel power planes. However, a scattering parameter measurement and full-wave electromagnetic simulation for their entire structure are costly and time consuming. This letter presents a two-dimensional dispersion-diagram analysis based on a unit-cell network of EBG structures by extending a well-known dispersion-diagram analysis of one-dimensional infinite periodic structures. The approach is extremely effective in computing stopband frequencies and provides the stopbands with good agreement to the measured results.

DOI： 10.1109/LMWC.2006.885587

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Determination of impedances in LECCS-I/O model by 3-port VNA measurement for higher frequency range

OSAKI Akihiro, IOKIBE Kengo, TOYOTA Yoshitaka, KOGA Ryuji, WADA Osami

IEICE technical report 106 ( 182 ) 17 - 22 2006.7

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

This report discusses impedance determination of a linear equivalent circuit (LEC) in an EMC macro model, LECCS I/O. The 2-port LECCS I/O model the authors had proposed based on 2-port measurement by a vector network analyzer (VNA) was found to be affected by an external circuit connected to the input terminals of CMOS gates. To remove the defect, this report investigated a 3-port LECCS I/O model with 3-port VNA. The 3-port model includes the input circuit of CMOS gates and the three ports of the model mean the power-supply terminal, the output terminal, and the input terminal to the ground terminal. The proposed 3-port model with 3-port VNA was used for power-ground impedance simulation by changing the impedances of external input and output circuits. As a result, the impedance simulation was in good agreement with measurements in higher frequency range compared with the previous 2-port model with 2-port VNA.

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EMI antenna model based on common-mode potential distribution for fast prediction of radiated emission Reviewed

Y. Sakai, T. Watanabe, O. Wada, T. Matsushima, K. Iokibe, Y. Toyota, R. Koga

IEEE International Symposium on Electromagnetic Compatibility 2 280 - 284 2006

Virtual Port Parameters in Segmentation Method for Modeling Power Bus Structures in Multilayer PCBs

Zhi Liang Wang, Osami Wada, Yoshitaka Toyota, Ryuji Koga

International Journal of Microwave and Optical Technology 2006

マイクロコントローラの多電源ピンLECCS-coreモデルの構築

中村克己, 南澤裕一郎, 豊田啓孝, 古賀隆治, 和田修己, 斎藤義行, 中村篤

電子情報通信学会論文誌 C 2006

バイスタティックライダによる水雲粒子径測定原理の検証

小林隆, 五百旗頭健吾, 杉本伸夫, 豊田啓孝, 古賀隆治

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 57th 2006

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