# About the PEEC method

## Origin

A global method to attribute a contribution to the total impedance to each part of a structure was proposed by A. E. Ruehli at the beginning of the 70s.

This is the PEEC method (Partial Element Equivalent Circuit).

On the basis of Maxwell's equations, A. E. Ruehli introduces the partial element concept in order to be able to model connections of an electric structure by using an electric circuit with lumped components (L, R and M).

## Definition

PEEC is a method which makes it possible to calculate precisely the resistance, the partial inductance and the mutual partial inductances of rectilinear conductors of rectangular cross-section.

Taking into account conductors of any cross-section can be done either by using numerical integration techniques or by subdividing the cross-section in rectangular basic elements (mesh concept).

## Principle/Theory underlying the method

The computation of resistances and partial inductances is based on the Ohm's law and on the line integral of the vector potential along the conductors respectively; it requires that the conductors be placed in a region where there are no nonlinear magnetic materials and that the current density on the conductor cross-section be uniform.

This last condition, which is incompatible with a frequency approach, is overcome by subdividing (concept of mesh) the conductors to take into account the variations of the current with the frequency.

The principle of the method is detailed in the following paragraphs.

## Utilization

This method allows the construction of equivalent electric circuits with localized components (partial elements) for different types of conductors.

Its use is restricted to rigid solid conductors.