On characterizing the impedance of power/ground planes - including the effect of anti-pads

In this contribution, the impedance of a power/GND plane pair with the inclusion of the effect of anti-pads (voids) is computed by applying a hybrid finite difference time domain (FDTD)-field theory procedure. The power/GND plane is analyzed by dividing the entire structure into a grid of square segments. Then each segment is replaced by an equivalent circuit module. The topology and elements of these modules are extracted by an analytical procedure, using the solution of Helmholtz equation while applying the FDTD method for regular regions. Then, an equivalent circuit topology is constructed by superimposition of all pre-made segments. This method is extended to include the anti-pads. The analytical/simulation results are presented, and those results are compared to the data obtained from preliminary measurements.