Signal Integrity and Radiated Emission of High-Speed Digital Systems

Appendix E

The Nodal Method to Calculate the Partial Inductance of Finite Ground Planes

In this appendix the nodal method for analysis in the frequency domain is introduced and applied to compute the effective partial inductance L_gnd associated with the return path of two typical trace structures in PCBs: a microstrip and a stripline with finite ground planes. This inductance is very important for Ground Loop Coupling (GLC) calculation (see Section 10.1) and radiated emission prediction (see Chapter 9). The method is validated by comparing the results with those obtained by SPICE and by the method of moments.

E.1 Nodal Method Equations

Consider a network with (N + 1) nodes (0 reference node and h = 1, 2,…,N remaining nodes) and B branches, each represented as in Figure E.1. Currents and voltages at each branch can be computed by the following equations in matrix form [1]:

where:

• and are the vectors containing respectively the independent voltage and current sources of the B branches. ...