Radio Wave Propagation
Refraction

A surface is considered smooth if the size of irregularities is small relative to the wavelength. Otherwise, it is considered to be rough. Electromagnetic waves are diffracted around intervening objects. If the object is small relative to the wavelength, it has very little effect. The wave will pass around the object undisturbed. However, if the object is large a shadow will appear behind the object and a significant amount of energy is reflected back toward the source. If the object is about the same size as the wavelength, things become quite complicated, and interesting diffraction patterns appear.

Use the interactive activity to calculate and graphically display the angle of refraction for different angles of incidence and different materials.

Radio waves also bend when entering different materials. This can be very important when analyzing propagation in the atmosphere. It is not very significant in WLANs, but it is included here, as part of a general background for the behavior of electromagnetic waves.


Interactive Media Activity

Interactive Activity: Optical Refraction

This activity shows how refraction works in different materials (starting from a vacuum).