RF Engineering for Wireless Networks

Chapter 4 Radio Transmitters and Receivers

1. Overview of Radios

1.1. The Radio Problem

It’s easy to build a radio. When I was a kid, one could purchase “crystal radio” kits, consisting of a wirewound inductor antenna, a diode, and an earpiece; by tuning a plug in the inductor, one could pick nearby AM radio stations quite audibly (at least with young pre-rock-amplifier ears). To build a good radio is harder, and to build a good cheap radio that works at microwave frequencies is harder still. That such radios are now built in the tens of millions for wireless local area networks (WLANs) (and the hundreds of millions for cellular telephony) is a testament to the skills and persistence of radio engineers and their manufacturing colleagues, the ...