There are two perspectives from which this chapter can be reviewed. First, it can be viewed as a sequence of specific examples that are useful for dealing with radio frequency, microwave, and optical systems. Secs. 13.1-13.3 are concerned with the propagation of energy along parallel plates, first acting as a transmission line and then as a waveguide. Practical systems to which the derived properties of the TEM and higher-order modes are directly applicable are strip lines used at frequencies that extend from dc to the microwave range. The rectangular waveguide of Sec. 13.4 might well be a section of "plumbing" from a microwave communication system, and the dielectric waveguide of Sec. 13.5 has many of the properties of an optical fiber. Second, the mathematical analysis of waves exemplified in this chapter is generally applicable to other more complex systems that are uniform in one direction.
When the structures described in this chapter are used to transport energy from one location to another, they are generally not terminated in "shorts" and "opens" and hence, generally, do not simply support standing waves. The object is usually to carry energy from an antenna to a receiver or from a generator to a load whether that be an antenna or a light bulb. Such energy transport is accomplished by the traveling waves featured in the next chapter.