Application notes: what's my impedance?

Although a lot of attention has been focused on the very capable and expensive 2.5-D and 3-D field solvers, there are many useful problems that can be done easily and quickly with an inexpensive 2-D cross-section solver. After a quick introduction to impedance calculation, we solved some basic microstrip and stripline problems. Any time you are learning to use a new tool, it is prudent to solve a few problems where the correct answer is known. Then you can move on to more interesting problems, like the CPW with overlay example and the shielded stripline example. This article was not intended to be a comprehensive review of these software packages, but rather a brief introduction to the concepts needed to calculate static transmission-line impedances.