MODELING AND REDUCTION OF CROSSTALK ON COUPLED MICROSTRIP LINE STRUCTURES AND MULTICHIP MODULES - AN FDTD APPROACH

The finite difference time domain modeling technique is used to model the near end and far end crosstalk on coupled microstrip structures us ed in multichip modules. The lines are terminated in lumped resistors which closely, but not exactly, match the lines. One line is excited b y a Gaussian voltage pulse produced by a Thevenin equivalent voltage s ource, It is shown that adding dielectric strips in the substrate belo w the conducting lines will reduce the peak crosstalk by as much as 80 %. Eight different configurations are modeled consisting of dielectric strips with different dielectric constant combinations, All configura tions are modeled with and without a metal case in order to make sure that the crosstalk reduction persists when the structure is enclosed i n a metallic enclosure (this would be the case for multichip modules), The results show that using dielectric strips with the smallest possi ble dielectric constant reduces crosstalk the most. (C) 1996 John Wile y & Sons, Inc.