TABLE OF CONTENTS It is an empirical fact that under investigation electric charge appears to exist in two forms, usually but not exclusively referred to as positive and negative. This chapter will attempt to explain the action of antennas in terms of an explanation of the nature of the interaction of these different types of charge when they are in motion within the structure of an antenna. This explanation of this interaction will be developed via the concept of the electromagnetic (EM) field.
The text in the main attempts to confine itself to the classical representations of field concepts, although as antenna theory concerns the propagation of EM energy between physically remote antennas at the speed of light it is not possible to completely ignore the relativistic aspects of antenna theory. This does not invalidate the approach that will be adopted as the principle equations used, based on the seminal work of James Clerk Maxwell, are, as will be seen in the text, themselves relativistically invariant in form.
However, as the concept of relative motion is fundamental to any understanding of the concept of magnetism, it can be helpful to bear in mind during any descriptions the following a priori principles of special relativity, these being:
The principle of the constancy of the speed of light, which states that the speed of light in vacuum will be measured to be c ? 3 10 8 m/s in all inertial frames of reference, irrespective of the state...
