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A new method to determine the reflection of substrate modes in finite substrate planar circuits is proposed. The perfectly matched layer (PML) concept is used to transform the open problem into a closed one. The discrete set of substrate, evanescent, and Berenger modes of the resulting anisotropic waveguides are then used in a mode-matching scheme to deduce the scattering coefficients of the substrate modes for oblique incidence on the edge of the substrate. We show results for single- and double-layered substrates and compare with finite-difference time-domain (FDTD) results. The combined perfectly matched layer (PML) mode-matching technique turns out to be very efficient.

We describe Delta-I noise caused by power plane resonances in multilayer boards. First, we study the effect of power plane resonances on the ground bounce of the system by performing finite-difference time-domain (FDTD) simulations. We simulate the voltage fluctuations at one point of the printed circuit board (PCB) due to a current surge between the power planes in a different point. Next, two methods to prevent this ground bounce effect are investigated. The first method consists of adding lumped capacitances to the design. The effect of one large capacitor is compared to the effect of adding a "wall" of smaller capacitors. A second approach is to isolate the chips by etching a slot around the sensitive integrated circuits (ICs) and connecting both sides by a small inductor. Both methods provide excellent protection against power plane resonances.

This study is concerned with efficient use of a high-level machine-independent language in the AMT DAP (distributed array processor) series of computers. The AMT DAP is a single instruction multiple data stream computer. The recent enhancement of Fortran-Plus is described. This enhancement removed the restrictions on array shapes and sizes, giving a language which is independent of the available hardware parallelism. The enhanced Fortran-Plus has been implemented on the AMT DAP using the concept of the virtual systems architecture (VSA). The power of enhanced Fortran-Plus in expressing parallel algorithms is demonstrated in certain application areas. To show that the higher level of language has been implemented on the general VSA system without compromising performance, the performance of these codes is discussed for a range of problem sizes. >

In recent papers the surface impedance condition is proposed to incorporate the effect of high conductivity of a material. This condition only takes the reflection at materials into account; the transmission through very thin layers is not considered. In this work, we introduce a similar approach to model both reflection and transmission when confronted with a thin layer of good, but not perfectly, conducting material.