Indoor Wireless Communications

4Radio Propagation

Radio wave propagation is a key topic for an in-building wireless system designer. The underlying theory that gives rise to the production of radio waves is reviewed here, which (alongside light) are examples of electromagnetic waves. The simplest form of wave is a plane wave, which illustrates many of the ways in which more complex waves interact with their surroundings (e.g. a building). The properties of materials (e.g. walls, windows, roofs and trees) are also explained, which are relevant to their impact on waves.

There is theoretically an infinite number of ways in which waves interact with materials, which can be broken down into a small number of mechanisms. By understanding each of these mechanisms in turn an appreciation of the nature of the effects that are observed in practical in-building design is developed. These mechanisms, combined with the complicated structure of real buildings, make the practical prediction of in-building propagation very challenging, as stated for the various environments in the previous chapter.

Propagation effects are so important to indoor radio design that an entire chapter is dedicated to a deeper study and understanding of such mechanisms. In fact, radio waves interact in many ways with building walls, furniture, people, etc., and depend on aspects such as construction materials so these should be carefully considered for more accurate work.

4.1 Maxwell's Equations

Radio wave propagation has its foundations in electromagnetic ...