Chapter 3
Radio-Frequency Engineering
Radio-frequency (RF) engineering is about systems that operate at radio frequencies such as microwave frequencies. Our approach to RF will be from a “signals and systems” perspective. The RF portion of radio transmitters and receivers will be viewed as a subsystem of wireless systems. Thus, the relationships of the RF portion to other parts of the overall wireless system design will be pertinent. For example, radio receiver sensitivity depends on the RF design, among other factors, and it has a direct influence on link budgets. Also, when we design wireless access technologies, we need to be aware of the RF subsystem capabilities; for example, a high peak-to-average power ratio (PAPR, Section 6.5.2) in signals causes distortion and/or inefficiencies in the RF subsystem because of the nature of RF amplifiers.
RF generally includes other aspects, such as the device technologies and RF circuits (including active circuits and passive circuits). These aspects are, however, outside our scope in this book, although the interested reader may consult some of the reference listed at the end of the chapter for details on those aspects. What is of interest in our “signals and systems” approach are aspects such as consideration of the noise contributions of the subsystems and indicators of dynamic range, sensitivity, selectivity, and so on. We are interested in these aspects because of their relationship to other aspects of overall wireless system design, ...
