Suppression of vertical electromagnetic coupling in multilayer packages

This paper proposes an effective approach to suppress vertical electromagnetic (EM) coupling in multilayer packages operating at GHz frequencies. In the case of packages with embedded actives where there are large apertures (die sized) in the metal planes and cavities in dielectric layers to accommodate the chips, the effect of EM field coupling is significant. The method involves EM band-gap structures for suppressing vertical coupling and the isolation band can be tuned over different frequency ranges. In addition, this paper puts forth a methodology for predicting the frequency range of the isolation band achieved by the coupling suppression technique. The proposed methodology is demonstrated through simulations and measurements.