Decoupling Capacitor Placement on Resonant Parallel-Plates Via Driving Point Impedance

A semi-analytical method is proposed to evaluate the effectiveness of a decoupling capacitor on resonant power and ground planes. New expressions are developed relating the pin impedance to relative placement of a capacitor with associated angular and distance parameters. To speed up the solution of resulting transcendental equations, a 2-D iterative technique is proposed, which yields the effective distance as well as the angle between a decoupling capacitor and a power pin. The partial derivatives of the corresponding Jacobian matrix are analytically derived. Numerical examples are presented to demonstrate the validity of the proposed method, which also investigates the effect of plane edges on pin impedance.