3. Measuring the radiation pattern

Determining the radiation pattern of an antenna involves studying the distribution of the electromagnetic field in a sphere centered on the antenna.

To characterize this diagram, we usually use site and bearing coordinates (defined on figure 1 ) and measure either the electric field in amplitude and phase, or more generally amplitude alone or power expressed in decibels (figure 1 ).

Measurements are generally taken in the main planes, such as Oy, Oz (site plane) and Oy, Ox (bearing plane). In some cases, measurements are taken over the entire sphere, with a sampling step that is small compared to the variations...