Acta Medica Okayama4712005Convergence acceleration and accuracy improvement in power bus impedance calculation with a fast algorithm using cavity modes29ENZhi LiangWangOsamiWadaYoshitakaToyotaRyujiKogaBased on the cavity-mode model, we have developed a fast algorithm for calculating power bus impedance in multilayer printed circuit boards. The fast algorithm is based on a closed-form expression for the impedance Z matrix of a rectangular power bus structure; this expression was obtained by reducing the original double infinite series into a single infinite series under an approximation. The convergence of the single series is further accelerated analytically. The accelerated single summation enables much faster computation, since use of only a few terms is enough to obtain good accuracy. In addition, we propose two ways to compensate for the error due to the approximation involved in the process of reducing the double series to the single series, and have demonstrated that these two techniques are almost equivalent.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama12003Modeling of gapped power bus structures for isolation using cavity modes1015ENZhi LiangWangOsamiWadaRyujiKoga<p>Power bus resonance characteristics of a gapped power-plane with a slit and a split power-plane with a gap were studied, using a fast algorithm based on a full cavity-mode resonator model and the segmentation method. Inductance and capacitance models were used to account for a field coupling along the slit and across the gap, respectively. Good agreements between the calculated and measured results were found to demonstrate the effectiveness and accuracy of our fast algorithm and the segmentation method, as well as the inductance model for the slit and the capacitance model for the gap. </p>No potential conflict of interest relevant to this article was reported.Acta Medica Okayama2003Analysis of resonance characteristics of a power bus with rectangle and triangle elements in multilayer PCBs7376ENZhi LiangWangOsamiWadaYoshitakaToyotaRyujiKoga<p>One of the major sources of radiated EMI is attributed to power bus resonance in a printed circuit board (PCB). A fast algorithm, combined with the segmentation method, is applied for calculating resonance characteristics of a power bus whose pattern consists of several segments of rectangles and/or right-angled triangles. Good agreement between the calculated and measured results demonstrates the usefulness and accuracy of the fast algorithm and the segmentation method. </p>No potential conflict of interest relevant to this article was reported.Acta Medica Okayama2002Application of segmentation method to analysis of power/ground plane resonance in multilayer PCBs775778ENZhi LiangWangOsamiWadaYoshitakaToyotaRyujiKoga<p>The fast algorithm developed for calculating the resonant characteristics of the power/ground planes in multilayer PCBs, is extended to the case of that the pattern of the power/ground planes consists of several "segments" of rectangles, using the so-called segmentation method. Good agreements between the calculated and measured results have demonstrated the usefulness and accuracy of our fast algorithm and the segmentation method.</p>No potential conflict of interest relevant to this article was reported.Acta Medica Okayama12003High-speed simulation of PCB emission and immunity with frequency-domain IC/LSI source models49ENOsamiWadaZhi LiangWangTetsushiWatanabeYukihiroFukumotoOsamuShibataEijiTakahashiHidekiOsakaShigekiMatsunagaRyujiKoga<p>Some recent results from research conducted in the EMC group at Okayama University are reviewed. A scheme for power-bus modeling with an analytical method is introduced. A linear macro-model for ICs/LSIs, called the LECCS model, has been developed for EMI and EMS simulation. This model has a very simple structure and is sufficiently accurate. Combining the LECCS model with analytical simulation techniques for power-bus resonance simulation provides a method for high-speed EMI simulation and decoupling evaluation related to PCB and LSI design. A useful explanation of the common-mode excitation mechanism, which utilizes the imbalance factor of a transmission line, is also presented. Some of the results were investigated by implementing prototypes of a high-speed EMI simulator, HISES. </p>No potential conflict of interest relevant to this article was reported.