A measure of the concentration of power in a radar beam. The beamwidth in a given plane is the angle subtended at the antenna and containing the main lobe within which the intensity in the far field o [..]

1. In the radio regime, of an antenna pattern, the angle between the half-power (3-dB) points of the main lobe, when referenced to the peak effective radiated power of the main lobe. Note: Beamwidth is usually expressed in degrees. It is usually expressed for the horizontal plane, but may also be expressed for the vertical plane. 2. For the optical [..]

An aerial acceptance angle measured between half- power points.

A measure of the ability of an antenna to focus signal energy towards a particular direction in space. The beamwidth is measured in a plane containing the direction of maximum signal strength. It is usually expressed as the angular separation between the two directions in which the signal strength is reduced to one-half of the maximum value (the -3 [..]

The measure of the 'width' of an antenna pattern, measured in degrees of arc. Generally an antenna with low gain has a wide pattern, receiving signals well from a number of different directi [..]