ABSTRACT
This chapter discusses transmission lines, which are used to carry signals, and the propagation of electromagnetic waves which encompasses antennae. Matching is vitally important to minimize reflections on transmission lines and in free space. An important parameter when dealing with transmitting stations is the voltage standing wave ratio (VSWR). The VSWR is the ratio of the magnitude of the maximum to the minimum standing wave voltage along the line. Short-circuited and open-circuited stubs are very useful elements for use in transmission lines. The Smith chart uses load impedance normalized to the transmission line impedance, i.e. resistance is R/Zo and reactance is X/Zo. Antennae are an essential part of a communications link, be it point to point or broadcast, transmitter or receiver. On the transmitter side, power travels up the feeder and into the antenna. There is usually a matching network which matches the antenna to the feeder.
