Calculation of PCB track impedance

Abstract

The value of the controlled impedance of various track configurations is usually obtained using algebraic equations. Most of these equations, particularly those for non‐zero track thickness, have been obtained by either theoretical approximations or curve‐fitting the results of numerical solutions of the basic electromagnetic equations. With the advent of modern PCs it is now possible to calculate the impedances directly and quickly, using numerical techniques. This has the advantage of improving the accuracy of the impedance value and increasing the range of validity. Furthermore, a wider range of configurations is now possible. The paper discusses the algebraic equations and numerical solutions in more detail.