As the use of electronic communication has increased over the years, the frequency spectrum normally used for radio signals has become extremely crowded. In addition, there has been an increasing need for more spectrum space to carry wider-bandwidth video and digital information. One of the primary solutions to this problem has been to move more radio communication higher in the spectrum, specifically the microwave range, the 1- to 300-GHz range.

In the past, because of the difficulty of generating, transmitting, and receiving microwave signals, only those who truly needed and could afford the special equipment used this part of the spectrum. Today, thanks to advances in semiconductor technology, microwaves are now being more widely used. This has opened the microwave spectrum to all sorts of new services which include wireless local-area networks, cellular and cordless phones, digital satellite radio, and wireless broadband, to name a few. In this chapter we take a look at some of the components and techniques used in modern microwave radios.