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→Directivity
=== Directivity ===
[[File:Isotropic3.gif|right|frame|Isotropic. Image reproduced from [https://commons.wikimedia.org/wiki/File:Isotropic_radiator_animation_240x240x8frame_0.4sec.gif here]]]
[[File:OmniOmni2.jpg|thumb|frame|200px|OmnidirectionalRadiation pattern of a 3λ/2 monopole antenna. Although the radiation of an omnidirectional antenna is symmetrical in azimuthal directions, it may vary in a complicated way with elevation angle, having lobes and nulls at different angles. Image reproduced from [https://en.wikipedia.org/wiki/Omnidirectional_antenna#/media/File:Vpol_dual_band_blade_antenna_blade_L1_3D.jpg here]]]
[[File:Directional.png|thumb|frame|200px|Directional]]
As the name suggests, directivity is the measure of how directed the antenna radiation pattern is. That is how much an antenna transmits in a particular direction as opposed to transmitting uniformly in all directions. The radiation pattern can be depicted as a function of azimuth angle and elevation angle. The ratio of max power in radiation pattern function to the average power of radiation gives us the directivity of any antenna. Mathematically, if F(Θ,Φ) denotes the radiation function, directivity can be described by: