DERIVATION OF EQUIVALENT-CIRCUITS FOR MULTILAYER PRINTED-CIRCUIT BOARD DISCONTINUITIES USING FULL-WAVE MODELS

Recent advances in increasing transmission rates for digital communica tion systems necessitates special attention during printed circuit boa rd (PCB) design. This contribution provides a methodology for developi ng appropriate simple equivalent circuits to describe the discontinuit ies in multilayer boards. The effects of inhomogeneous substrate mater ial, via holes, crossovers and coupled lines are examined. The incorpo ration of substrate loss in the difference equation system is addition ally treated. The equivalent circuits are intended for system simulati on, where minimal computational overhead is desired. The Finite Differ ence Frequency Domain (FDFD) and Finite Difference Time Domain (FDTD) methods provide in conjunction the basis for calculating the scatterin g parameters [S] and fields of the discontinuities, from which equival ent circuits are derived. Excellent S parameter agreement between fiel d computation and equivalent circuit is achieved upto 20 GHz for all s tructures considered. Measurements are indicated where appropriate.