Toru Yamada

Georgia Institute of Technology, Atlanta, GA, United States

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Publications (7)0.13 Total impact

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    ABSTRACT: A high-accuracy modeling methodology for electrical characteristics of transmission electrodes on SAW substrates is established. In order to design SAW filter accurately, it is necessary to extract precise SAW material parameters from the measurement value of the reference SAW resonator. When measuring the SAW resonator, transmission lines are needed for feeding to contact probes. De-embedding procedure, which removes the influence of transmission lines, is very important for accurate characterization of the SAW resonator. In this paper, we apply the improved de-embedding procedure using Short, Open, and Thru calibration patterns. The de-embedded transmission line is separated in four parts and extracted the RLGC equivalent circuit model for each part. Furthermore, we derive the frequency characteristic of resistance element of the transmission line. Finally, de-embedding the transmission line accurately, we can get intrinsic characteristic of the SAW resonator. This method must be very useful to extract SAW material parameters and we can design SAW filters more effectively. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(2): 49–55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10230
    No preview · Article · Feb 2009 · Electronics and Communications in Japan
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    ABSTRACT: Differential lines are extensively used in high-speed digital circuits due to their ability to improve signal integrity by rejecting common-mode noise. However noise is injected into differential signals when there are irregularities in the signaling setup. These anomalies may be via transitions of differential lines through power planes in power distribution systems, via stubs, asymmetric lengths of differential lines, different transition points for each of the differential vias etc. This paper quantifies noise due to irregular differential structures in frequency domain. Presence of noise in differential signaling is verified through a set of test vehicles. The effect of signal to power coupling from differential lines on signal jitter is also investigated.
    Preview · Conference Paper · Jun 2008
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    ABSTRACT: The coupling of simultaneous switching noise (SSN) in mixed signal system on package modules is a critical signal and power integrity (SI/PI) problem. In the presence of split planes and apertures, SSN coupling occurs both horizontally as well as vertically across layers. Thus, to catch SI and PI problems at an early stage of design requires fast signal and power co-simulation methodologies. In this paper, we outline the multi-layer finite difference method and how the accuracy of the technique can be enhanced with models for fringe and gap effects. We then briefly describe a method for integrating the signal distribution network with the power distribution network to enable co-simulation. The method is then applied to a mixed signal board containing split planes, and numerical results are compared to full-wave simulations.
    Preview · Conference Paper · Aug 2007
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    ABSTRACT: Power integrity simulation for system-on-package (SoP) based modules is a crucial bottleneck in the SoP design flow. In this paper, the multi-layer finite difference method (M-FDM) augmented with models for split planes has been proposed as a fast and accurate frequency domain engine. Results demonstrating the accuracy and scalability of the method have been presented. In particular, the algorithm was employed to the analysis of a realistic 6 layer package with ~ 200k nodes.
    Preview · Conference Paper · Jul 2007
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    ABSTRACT: Packages for modern mixed signal systems in package (SiP) require split planes and power islands to isolate multiple power supplies. To reduce design iterations due to signal integrity issues, the frequency response of the package needs to be obtained accurately at an early stage of the design. Full-wave EM solvers are generally the most accurate tools available. However, the high time and memory required by such tools relegates their use to final verification, at which stage design iterations are expensive. The finite difference method has been shown to be efficient in simulating single plane-pair structures with slots as long as one plane is completely solid. Also, the multilayer finite difference method (M-FDM) can accurately model multilayer structures with apertures, so long as there are no power islands. In this paper, a formulation for efficient simulation of multilayer structures with split planes has been investigated. Further, a method by which transmission lines can be integrated with a power distribution network containing apertures and split planes has been discussed. The formulation has been validated by comparing results with full-wave EM simulations.
    Preview · Conference Paper · Jul 2007
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    ABSTRACT: Full-wave EM simulations are computationally expensive given the complexity of packaging structures in modern mixed signal systems. Fast methods such as the transmission matrix method are inaccurate as they do not model discontinuities such as metal edges and gaps. In this paper, simple models for the edge effect and gap coupling are developed for the finite difference frequency domain method. Results are presented comparing the accuracy of the proposed method with full-wave simulations and measurements
    Preview · Conference Paper · Nov 2006
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    ABSTRACT: In this paper, we propose a method of analyzing the excitation and detection of leaky modes in a surface acoustic wave (SAW) waveguide structure. These properties could not be directly evaluated by the conventional scalar potential theory and mode expansion. In the present theory, the SAW excitation and detection are taken into account in the scalar potential theory, and then the SAW signal transfer between input and output ports is estimated in a form of the Fourier transform in the wavenumber domain. Finally, the contribution of each mode is estimated by the residue theorem. This method is effective in estimating the contribution of complete spectra, including leaky modes as well as non-leaky guided modes.
    No preview · Conference Paper · Nov 2002