#

The illustration displays the zenith angle theta, in degrees from 88 to 92. The azimuth angle phi, in degrees, ranges from negative 2 to 2. The normalized radiation intensity, in d B, ranges from negative 30 to 0.

The illustration displays that each specific combination of the zenith angle q and the azimuth angle f denotes a specific direction in the spherical coordinate system. The normalized radiation intensity F (q, f) characterizes the directional pattern of the energy radiated by an antenna, and a plot of F (q, f) as a function of both q and f constitutes a three-dimensional pattern.