Signal propagation over perforated reference planes in stripline interconnect structures

An experimental and theoretical investigation of signal propagation in high-speed interconnect structures containing perforations in the reference planes is presented. Discontinuities of this type occur in many practical package designs and must be modeled correctly (in the time-domain) in order to account for the additional noise which is introduced on the signal line. To establish valid modeling techniques for this class of interconnects, measurements are made on two custom-designed test structures and compared with results obtained from simulation. The effect of the reference plane discontinuity is studied as a function of signal conductor height for a standard stripline configuration. Two- and three-dimensional parasitic extraction tools, along with full-wave electromagnetic solvers, are used to calculate the discontinuity element values. For both test structures, good correlation is obtained between measurements and modeling results. The value of different modeling approaches is discussed, and design guidelines for practical interconnect structures are proposed