Modeling and Simulation of Planes With Decoupling Capacitors

Based on the resonant cavity model, this paper presents a modeling approach for power/ground planes with decoupling capacitors. A bare plane pair is first modeled by the resonant cavity model. Then, decoupling capacitors are divided into segments according to port coefficients, capacitance, the number of decoupling capacitors, and the frequency response of each mode of the resonant cavity model. To get the model of the plane pair with decoupling capacitors, divided segments are incorporated into the resonant cavity model. By this way, not only the influence of decoupling capacitors on each single mode, but also the frequency responses of capacitors in each mode can be reflected. By being incorporated with the segmentation method and the physics-based modeling method, this modeling method can be extended to handle the irregular-shaped and multilayered power/ground plane with capacitors, respectively. Based on the impedance distribution throughout the whole power/ground plane pair, the effective decoupling radius of a capacitor and its variation trends with frequency, capacitance, and parasitic parameters are extracted and analyzed.