TABLE OF CONTENTS Components, those bits and pieces which make up a radio frequency (RF) circuit, seem at times to be taken for granted. A capacitor is, after all, a capacitor isn t it? A 1-megohm resistor presents an impedance of at least 1 megohm doesn t it? The reactance of an inductor always increases with frequency, right? Well, as we shall see later in this discussion, things aren t always as they seem. Capacitors at certain frequencies may not be capacitors at all, but may look inductive, while inductors may look like capacitors, and resistors may tend to be a little of both.
In this chapter, we will discuss the properties of resistors, capacitors, and inductors at radio frequencies as they relate to circuit design. But, first, let s take a look at the most simple component of any system and examine its problems at radio frequencies.
Wire in an RF circuit can take many forms. Wirewound resistors, inductors, and axial- and radial-leaded capacitors all use a wire of some size and length either in their leads, or in the actual body of the component, or both. Wire is also used in many interconnect applications in the lower RF spectrum. The behavior of a wire in the RF spectrum depends to a large extent on the wire s diameter and length. Table 1-1 lists, in the American Wire Gauge (AWG) system, each gauge of wire, its corresponding diameter, and other characteristics of interest to the RF circuit designer. In the AWG system, the diameter of a wire will...
