Analysis of Interconnects Routed Under PMC Based Heat Sinks

Perfect Magnetic Conductor (PMC) surfaces typically used for inhibiting resonances in metal enclosure are demonstrated to be effective also for limiting the unintentional EM radiation guided by the IC heat sink and the PCB ground plane. This PMC surface is realized by appropriately placing array of conductive pins under the heat sink and around the IC. Microstrip interconnects routed from/toward the IC are numerically analyzed to verify the impact of the close conductive pins on single-ended and differential traces; the crosstalk is analyzed as well to provide comprehensive guidelines for microstrip routing when a pinned heat sink is employed. If the layout is appropriately designed, the signal transmission and the crosstalk of microstrip interconnects are the same as the reference case of a heat sink without pins