Editing Radiant intensity (section)

==Radio-frequency engineering==
Radiant intensity is used to characterize the emission of radiation by an [[Antenna (radio)|antenna]]:<ref name="Antennas_for_all_applications">{{cite book|title=Antennas for all applications|edition=3rd|first1=John|last1=de Kraus|first2=Ronald J.|last2=Marhefka|date=2002|publisher=McGraw-Hill |isbn=0-07-232103-2}}</ref>
:<math>I_{\mathrm{e},\Omega} = E_\mathrm{e}(r) \, r^2,</math>
where
*''E''<sub>e</sub> is the [[irradiance]] of the antenna;
*''r'' is the distance from the antenna.

Unlike power density, radiant intensity does not depend on distance: because radiant intensity is defined as the power through a solid angle, the decreasing power density over distance due to the [[inverse-square law]] is offset by the increase in area with distance.