The Fundamentals of Radio Wave Propagation

How do radio waves get from one location to another? Why does a signal at generated at Point A, which is several thousand miles away, reach Point B without a complicated myriad of connecting wires? The answer, in three words, is radio wave propagation. Radio wave propagation theory is of particular importance to wireless communications, for, without a preliminary understanding of the physical nature of wave propagation it is impossible to ensure that communications can be established at all.

Transmission and Reception

In a wireless environment radio frequencies are transmitted outward from a source, which is usually an antenna. Antennas provide the link between the grounded and free-space parts of a communications system. The transmitting antenna is charged with the task of transforming the electrical signal into electromagnetic radiant energy, the purpose of the receiving antennae is to accept the received radiated energy and efficiently convert it into an electrical signal for processing by the receiver. The portion of the electromagnetic spectrum that constitutes radio waves ranges from about 30 kHz to 300 GHz. (Fig. 1)

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