Robert Lacoste's The Darker Side

Chapter 1 Impedance Matching Basics

Note: This chapter is partially based on the column “The darker side: Antenna basics,” Circuit Cellar, no. 211, February 2008.

Let’s start our exploration of the darker side with a quite simple but often misunderstood topic: impedance matching. As we will see, this concept is fundamental for all radio and small signal designs, basically because radio signal power is expensive and must be well used. Just try to replace your 50-m 75-ohm TV antenna cable with a 50-ohm cable to understand what I mean: You may be disappointed with the image quality. However, matching is now also fundamental in nearly all high-speed digital designs. Our standard PC motherboard, with its GHz clock, will simply not work at all if ...