Coupling behavior between transmission lines with meshed ground planes in LTCC-MCMs

Multilayer ceramic modules for high speed digital applications use meshed planes between the signal layers for shielding and power supply. Both wave impedances of the signal lines and coupling behavior between different signal layers are influenced by the properties of these meshed planes. Former investigations have shown that for a constant metallization rate (aperture ratio) and a given line width, the wave impedance is nearly constant over a wide range of grid pitches. The coupling behavior (near- and far-signal crosstalk) is explained by practical investigations of different test modules and three-dimensional (3-D) time-domain field simulations. It has been observed that coupling between layers depends on the metallization rate and the position of lines over the grid. One aim is to determine the optimal configuration for minimum couplings.