Inductive Network Model for the Radiation Analysis of Electrically Small Parallel-Plate Structures

Vertical interconnections between parallel-plate structures as often encountered in electronic designs are the source of various signal integrity and radiated-emission issues. The presented analysis is based on a coupled multiport equivalent-circuit model for frequencies below the first cavity resonance. A main subject is the determination of the self- and mutual port inductances, for which exact closed-form expressions are presented. For special port positions simple approximate formulas are derived. The results show that the considered structure is inherently resonant. The resonance frequency depends on the number and configuration of the ground interconnections and can be estimated from the equivalent circuit. The radiated emission of the whole structure is determined by the capacitive current in the network model, based on a simple Hertzian-dipole radiation characteristic. The model is validated by numerical 3-D field simulations and measurements.