Physical Principles of Wireless Communications, 2nd Edition

CHAPTER 3

Antennas

Antennas are the structures used to interface between the transmitter and the wave propagation medium. The transmitter power excites currents on the antenna that, in turn, launch electromagnetic waves. Antenna gain, which is a measure of its effectiveness in focusing the electromagnetic wave power toward an intended receiver, is a key parameter in designing a wireless communication system. The connection between currents on the antenna structures and the pattern of the electromagnetic radiation they produce is described by Maxwell’s equations. Thus, for the sake of intellectual integrity, we begin our description of antennas with a review of Maxwell’s equations and a derivation of the inhomogeneous Helmholtz equation relating ...