TABLE OF CONTENTS An understanding of the mechanism by which energy is radiated from a circuit and the derivation of equations for expressing this radiation involve conceptions which are unfamiliar to the ordinary engineer.
Frederick Emmons Terman, 1932
Much has changed since Frederick Emmons Terman's day, when the process of electromagnetic radiation was an esoteric subject not of interest to the "ordinary engineer" [1], Even today, however, one need not delve into the technical details of how antennas work in order to make good use of them. In many applications, an antenna may be thought of as a transducer that couples between signals on a transmission line and radio waves in space. From this point of view, antennas are black boxes whose properties are defined by such parameters as bandwidth, pattern, gain, and matching, among others. The transducer viewpoint is valuable for anyone who wants to know how to use an antenna and what an antenna does but is not interested in the details of how an antenna works or how to design one.
Traditionally, engineers study antennas from the "frequency domain" point of view. The frequency domain point of view breaks down physical processes into sine waves of infinite duration with no particular beginning or end. The frequency domain further assumes "steady-state," or time average, behavior. Thus, initiates in frequency domain analysis generally speak of antennas as radiating "power." The frequency domain is best suited for studying single-frequency or relatively narrowband systems operating in a steady-state mode.
An alternate way of...
