Chapter 4. Other Components

There are many other components used in RF systems beyond the five basic ones covered in the previous chapter. Some of these components are very simple to understand while others are more complex. Most of these other components exist to accomplish one of two objectives. They either send the RF signal in a different direction—or in multiple directions—or they change the size or shape of the signal. All of these "other" components are used in RF systems to effectively implement wireless communications, keeping in mind that the objective at any moment in time is to have a perfect sine wave, of the exact size required, at only one frequency.

This chapter covers nine more components, and their derivatives, used in RF systems. Switches, dividers, combiners, couplers, circulators, and isolators all reroute the RF signal in one or more directions within the system. A major design objective for these components is to minimize insertion loss while rerouting the signal. Attenuators, transformers, and detectors, on the other hand, change the size and/or nature of the RF signal while keeping its shape unchanged. And, like the components covered in the previous chapter, each of these other components can be manufactured to optimize one or two key parameters. At least one example is given where each of these is used in a wireless system.

Unlike the five components covered in Chapter 3, these listed here tend to be manufactured by fewer companies, since they are used less frequently. This offers smaller manufacturers an opportunity to carve out small, but profitable, niches producing these devices.

There are other, more esoteric, components used in RF that are outside the scope of this book. (If you really want to learn about them, get an engineering degree.) The goal of this chapter is to give you an appreciation for how the complexity of an RF circuit can grow beyond that of the five basic components used in a transmitter and receiver.