Chapter 2
Introduction to Radio Frequency, Antennas, and Propagation
In this chapter we review selected topics in electromagnetics that provide foundational support for our coverage of radio frequency (Chapter 3), antennas (Chapter 4), and propagation (Chapter 5). We begin in Section 2.1 with a review of some mathematical tools for computing scalar and vector quantities that are typically used in basic electromagnetics. We then review electrostatics and magnetostatics in Section 2.2. Time-varying situations, wave propagation, and transmission lines are examined in Section 2.3. A brief comparison of different notions of impedance is presented in Section 2.4, followed by an introduction to test and measurement equipment in Section 2.5.
2.1 Mathematical Preliminaries
Here we review briefly some mathematical tools for working with scalar and vector functions in three dimensions.
2.1.1 Multidimensional/Multivariable Analysis
In Section 1.2.4 the signals concerned were measured at one place in a circuit (e.g., the voltage between two fixed points), where spatial dimensions were not important. Furthermore, the signals were all scalar functions. Now we extend our signal concepts, as well as concepts of sinusoids and phasors, into one or more spatial dimensions. Furthermore, the signals may be vector functions, not just scalar functions. For example, we might have a scalar 39 function, ρ, of coordinates x, y, and z (and time t) ρ(x, y, z, t), that we may also write as ρ(A, t), where
