研究者詳細 - 豊田　啓孝

論文 - 豊田　啓孝

分割表示 114 件中 21 - 40 件目／全件表示 >>

Co-simulation Analysis of Mode Conversion Due to Imbalance difference by Structural Discontinuity 査読

Sho Kanao, Hiroaki Iwasaki, Kengo Iokibe, Yoshitaka Toyota

2022 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC 2022) 2022年9月

FPGA Switching Current Modeling Based on Register Transfer Level Logic Simulation for Power Side-channel Attack Prediction

Masaki Himuro, Kengo Iokibe, Yoshitaka Toyota

IEEE International Symposium on Electromagnetic Compatibility 2022-September 172 - 177 2022年9月

担当区分：最終著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

We investigated the prediction of side-channel leak-age on the power delivery network (PDN) outside a cryptographic IC. To predict the leakage, it is necessary to estimate the switching current caused by the switching activity. So far, high temporal resolution estimation based on gate-level logic simulation has been proposed, but due to the decoupling property of the PDN, the switching current leaking out of the IC chip attenuates signif-icantly. Therefore, this paper calculates the mean of the switching currents over the clock period based on register transfer level (RTL) logic simulation, and then approximates it into a triangle waveform. This approach enables us to simulate the switching current faster than with gate-level simulation. In addition, the simulation time is further shortened by calculating the switching current only to the targeted round of a cryptographic algorithm (AES). Switching currents of the previous rounds were given as statistical models with the same sample mean and variance as the targeted round. As a result of simulating the switching current of an FPGA with the proposed method, we were able to obtain the low-order harmonic components of the current in almost the same magnitude as the gate-level simulation. We also simulated correlation power analysis (CPA) results for the printed circuit board on which the FPGA with the AES circuit was mounted, and found that the proposed method could predict the dynamic power supply voltage observed on the board and CPA results with sufficient accuracy.

DOI： 10.1109/EMCEurope51680.2022.9900948

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Suppression of Power-Bus Resonance and Unintentional Radiation by Lossy Resonator Filter

Sho Kanao, Shuhei Kodama, Kengo Iokibe, Yoshitaka Toyota

IEEE International Symposium on Electromagnetic Compatibility 2022-September 361 - 365 2022年9月

担当区分：最終著者,　責任著者掲載種別：研究論文（国際会議プロシーディングス）

We previously proposed a lossy resonator filter to suppress the parallel-plate resonance of printed circuit boards (PCBs). The filter consists of an open stub (a quarter-wavelength resonator) covered with a ferrite thin film (inducing a small loss). This paper evaluates the effect of the small loss by investigating the suppression of parallel-plate resonance and the unintentional radiation from a PCB with or without the ferrite thin film. An open stub can work as a narrow-band filter but may also work as an antenna and radiate unintentionally, which causes a secondary noise problem at frequencies other than the target frequency of 2.4 GHz. The electric field distribution between the parallel plates and the total radiated power were thus investigated to validate the effect of the small loss of the lossy resonator filter. The results showed that the total radiated power from parallel plates resonating at 2.4 GHz was suppressed by about 12 dB by using open stubs with a resonant frequency of 2.4 GHz, regardless of the presence or absence of the ferrite thin film. At 2.54 GHz, however, the open stubs without ferrite increased the radiated power by about 10 dB, whereas those with ferrite did not increase it at all. It was thus found that the lossy resonator filter could suppress not only the parallel-plate resonance but also unintentional radiation around the target frequency without causing any other problems.

DOI： 10.1109/EMCEurope51680.2022.9901324

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Multi-Objective Design of Filter Installed in Brush Motor by Preference Set-based Design Accounging for Cable Length 査読

Shohei Kan, Ryuta Nakanishi, Zhenhong Xu, Kengo Iokibe, Yoshitaka Toyota

2022 IEEE International Symposium on Electromagnetic Compatibility and Signal/Power Integrity, EMCSI 2022 595 - 595 2022年8月

A Study for Improving Signal-to-Noise Ratio Measurement Method in Side-Channel Information Leakage of Cryptographic Hardware 査読

Kengo Iokibe, Masaki Himuro, Yoshitaka Toyota

2022 IEEE International Symposium on Electromagnetic Compatibility and Signal/Power Integrity, EMCSI 2022 294 - 298 2022年8月

担当区分：最終著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Once the signal-tu-noise ratio (SNR) of the side- channel (SC) leakage trace is known, the intensity of the SC information leakage source inside the integrated circuit (IC) can be identified from measurements carried out outside the IC, SNR observation of SC leakage can also make it possible to set quantitative design targets to achieve the demanded leakage intensity. We discuss an improved method for identifying the SNR of SC leakage traces composed of multiple transient responses of IC switching current. The IC switching current repeatedly occurs as the IC runs the cryptographic operation since the cryptographic algorithm repeats a set of sub-operations. The method was applied to simulated and measured leakage traces to eliminate the effect of transient IC switching current caused before the target sub-operation was processed. As a result, a transient component more extensive than the signal component of side-channel analysis was identified in the decoupling capacitor configuration, where the convergence of the transient response is slow. In addition, the correlation coefficients obtained by the correlation power analysis, a major side-channel analysis method, were plotted as a function of SNR, and the plot of the simulated traces agreed with the theoretical curve. On the other hand, some errors remained in the plot of the measured traces.

DOI： 10.1109/EMCSI39492.2022.9889660

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Detection of AC magnetic field distribution using optical magnetometer with digital micro-mirror device 招待査読

Shuji Taue, Takumi Tanaka, Hiroto Suzuki, Yoshitaka Toyota

Optical Technology and Measurement for Industrial Applications Conference 2022 2022年4月

An Approach to Identify Noise-source Parameters of DC-DC Converter and Predict Conducted Emissions with Different Loads 査読

Shuqi Zhang, Kengo Iokibe, Yoshitaka Toyota

IEEE Letters on Electromagnetic Compatibility Practice and Applications 1 - 1 2022年

Common-mode Current Reduction by Applying Mode-conversion Suppression Technique to Power Delivery Network as Side-channel Attack Countermeasure

Md. Ashraful Islam, Masaki Himuro, Kengo Iokibe, Yoshitaka Toyota

2021 International Conference on Computer, Communication, Chemical, Materials and Electronic Engineering (IC4ME2) 2021年12月

Mode Conversion Suppression at the Discontinuity point on Power Delivery Network for Side-channel Attack Countermeasure

Md. Ashraful Islam, Masaki Himuro, Kengo Iokibe, and Yoshitaka Toyota

2021年12月

A Study for Low Calculation Cost Side-Channel Resistance Prediction Based on Transfer Impedance of Leakage Path 査読

Kengo Iokibe, Masaki Himuro, Yoshitaka Toyota

2021 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC) 2021年9月

An Approach to Predicting Conducted Noise from DC-DC Converter Accounting for Switching Fluctuation 査読

Shuqi Zhang, Kengo Iokibe, Yoshitaka Toyota

2021 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC) 2021年9月

Noise-Source Parameter Identification Considering Switching Fluctuation of DC-DC Converter 査読

Shuqi Zhang, Taishi Uematsu, Kengo Iokibe, Yoshitaka Toyota

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium 186 2021年7月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes noise-source parameter identification of the noise-source equivalent-circuit model for predicting conducted noise while considering the switching fluctuation of a DC/DC converter. We decomposed measured conducted noise into ripple noise, turn-on spike noise, and turn- off spike noise to prevent the accuracy degradation in the parameter identification. The predicted conducted noise spectra show the error with the measurement was within 3 dB up to 200 MHz, which is more accurate than that in our previous study.

DOI： 10.1109/emc/si/pi/emceurope52599.2021.9559182

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Efficient Estimation of Noise Suppression Amount in Power Bus with Decoupling Capacitors Using Lossy Resonator Filters 査読

Sho Kanao, Kengo Iokibe, Yoshitaka Toyota

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium 323 2021年7月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

To estimate the amount of noise suppressed by lossy resonator filters (LRFs) in a power bus with a decoupling capacitor, we used an equivalent circuit model considering the effect of the capacitor to know the suppression mechanism using the LRF. The discrepancy between the model and a full-wave simulation was approximately 2 dB.

DOI： 10.1109/emc/si/pi/emceurope52599.2021.9559213

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Practical Design Methodology of Mode-Conversion-Free Tightly Coupled Asymmetrically Tapered Bend for High-Density Differential Wiring 査読

WANG Chenyu, IOKIBE Kengo, TOYOTA Yoshitaka

IEICE Transactions on Communications E104.B ( 3 ) 304 - 311 2021年3月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人電子情報通信学会

The plain bend in a pair of differential transmission lines causes a path difference, which leads to differential-to-common mode conversion due to the phase difference. This conversion can cause serious common-mode noise issues. We previously proposed a tightly coupled asymmetrically tapered bend to suppress forward differential-to-common mode conversion and derived the constraint conditions for high-density wiring. To provide sufficient suppression of mode conversion, however, the additional correction was required to make the effective path difference vanish. This paper proposes a practical and straightforward design methodology by using a very tightly coupled bend (decreasing the line width and the line separation of the tightly coupled bend). Full-wave simulations below 20GHz demonstrated that sufficient suppression of the forward differential-to-common mode conversion is successfully achieved as designed. Measurements showed that our design methodology is effective.

DOI： 10.1587/transcom.2020ebp3056

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Evaluation of Side-Channel Leakage Simulation by Using EMC Macro-Model of Cryptographic Devices 査読

YANO Yusuke, IOKIBE Kengo, TESHIMA Toshiaki, TOYOTA Yoshitaka, KATASHITA Toshihiro, HORI Yohei

IEICE Transactions on Communications E104.B ( 2 ) 178 - 186 2021年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人電子情報通信学会

Side-channel (SC) leakage from a cryptographic device chip is simulated as the dynamic current flowing out of the chip. When evaluating the simulated current, an evaluation by comparison with an actual measurement is essential; however, it is difficult to compare them directly. This is because a measured waveform is typically the output voltage of probe placed at the observation position outside the chip, and the actual dynamic current is modified by several transfer impedances. Therefore, in this paper, the probe voltage is converted into the dynamic current by using an EMC macro-model of a cryptographic device being evaluated. This paper shows that both the amplitude and the SC analysis (correlation power analysis and measurements to disclosure) results of the simulated dynamic current were evaluated appropriately by using the EMC macro-model. An evaluation confirms that the shape of the simulated current matches the measured one; moreover, the SC analysis results agreed with the measured ones well. On the basis of the results, it is confirmed that a register-transfer level (RTL) simulation of the dynamic current gives a reasonable estimation of SC traces.

DOI： 10.1587/transcom.2020ebp3015

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Suppression of Mode Conversion at Ethernet Connector by using Modal-Equivalent Circuit Model based on Imbalance Matching 査読

Islam Md. Ashraful, Iokibe Kengo, Toyota Yoshitaka

電気学会論文誌．Ａ 140 ( 12 ) 586 - 592 2020年12月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人電気学会

When a shielded-twisted-pair (STP) cable is connected with a printed circuit board (PCB) via an Ethernet (RJ45) connector, mode conversion between primary- and secondary-common modes occurs at the connector section due to their structural difference that causes the difference in the imbalance factor of the transmission line. In this paper, we investigate the suppression of the mode conversion at the connector section by using a modal-equivalent circuit model based on imbalance matching. We focus on improving the PCB pattern below the shielded Ethernet connector by placing a copper layer on the PCB surface, and the inadequate shielding at the connector section by soldering and wrapping with copper tape. The application of this improvement based on imbalance matching at the connector section makes the imbalance factor of the connector section closer to that of the cable section and results in the suppression of the mode conversion. Based on the concept of imbalance matching, we confirmed the effect of the shield-improved connector with an improved PCB pattern on the suppression of the mode conversion at the connector section through circuit simulation and measurement, and it was validated that the circuit simulation results obtained from the modal-equivalent circuit model agree well with the measurement results.

DOI： 10.1541/ieejfms.140.586

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M系列変調TDRによる有線ネットワークのインピーダンス不連続点特定の基礎検討査読

亀山大樹, 五百旗頭健吾, 豊田啓孝

電子情報通信学会技術研究報告(Web) 120 ( 20(EMCJ2020 5-10) ) 2020年9月

Two-port Noise Source Equivalent Circuit Model for DC/DC Buck Converter with Consideration of Load Effect 査読

Shuqi Zhang, Taishi Uematsu, Kengo Iokibe, Yoshitaka Toyota

2020 International Symposium on Electromagnetic Compatibility - EMC EUROPE 2020年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

As the conducted disturbance of a power converter changes with its load value, the relationship between the electromagnetic interference of the power converter and its load needs to be investigated. This work examines a 2-port equivalent circuit model for a DC/DC buck converter with consideration of the load effect. Factors that influence the model accuracy are also discussed. We used a synchronous buck converter operating under a continuous conduction mode condition to determine the load effect and evaluate the model. Results showed that the input port of the fixed-load model and load-variable model had good accuracy up to 70 MHz. We also predicted the load effect on input port noise and found that the input port noise of an 8.2-? load could be predicted from the other two load values (6.6 ? and 11.6 ?).

DOI： 10.1109/emceurope48519.2020.9245680

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Suppression of Mode Conversion Due to Asymmetric Geometry of Dense Parallel Traces in Differential-Transmission Lines 査読

Tomoya Takeuchi, Kengo Iokibe, Yoshitaka Toyota

2020 International Symposium on Electromagnetic Compatibility - EMC EUROPE 2020年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Symmetry is important for differential-transmission lines, but the dense parallel traces easily break the symmetry due to coupling with the adjacent conductor, leading to mode conversion. We propose an asymmetric geometry of differential-transmission lines placed on the side of a nonadjacent conductor to suppress mode conversion and maintain signal integrity in the cases of loosely coupled and tightly coupled parallel traces. By designing the asymmetric geometry of dense differential-transmission lines by taking into account coupling with the adjacent conductor, mode conversion was successfully suppressed by decreasing the line width on the side of the non-adjacent conductor. It was also found that the asymmetric geometry can suppress mode conversion and maintain signal integrity in tightly coupled parallel traces. In loosely coupled parallel traces, on the other hand, the tightly coupled asymmetrically tapered bend we previously proposed suppresses mode conversion.

DOI： 10.1109/emceurope48519.2020.9245880

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Estimation of Power-bus Noise Suppression by Lossy Resonator Filter Using Lumped-constant Multi-ports Equivalent Circuit Model 査読

Sho Kanao, Kengo Iokibe, Yoshitaka Toyota

2020 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (2020 IEEE EMC+SIPI) 2020年8月

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