ABSTRACT
The simplest emitters of electromagnetic waves are accelerated electric charges and oscillating electric dipoles in the form of a line segment or conductor through which an alternating current exists. The electric charges in the conductor follow an oscillatory motion, so the alternating current carrying conductor acts as an antenna. An antenna transforms the oscillations of charges into free waves that are radiated in certain directions that depend on the geometry of the antenna. This chapter discusses different types of antennas and shows a simplified scheme of generation of electromagnetic waves by a Hertz dipole. Antennas also differ in their operating ranges. Operating wavelength range is the range within which the antenna retains its essential characteristics (directed action, the polarization structure of the field) with a given accuracy. The chapter also includes exercise problems related to emission of electromagnetic waves.
