In fiber optics, half the vertex angle of the cone of light emitted at the exit face of an optical fiber.
Note: The cone boundary is usually defined (a) by the angle at which the far-field irradiance has decreased to a specified fraction of its maximum value or (b) as the cone within which there is a specified fraction of… (Read More →)

At a given frequency, the ratio of the power radiated to the total power supplied to the radiator.

Synonym far-field region.

For an optical fiber, an unbound mode.
Note: In an optical fiber, a radiation mode is one having fields that are transversely oscillatory everywhere external to the waveguide, and which exists even at the limit of zero wavelength. Specifically, a radiation mode is one for which where is the imaginary part (phase term) of the axial propagation constant, integer is… (Read More →)

1. The variation of the field intensity of an antenna as an angular function with respect to the axis.
Note: A radiation pattern is usually represented graphically for the far-field conditions in either horizontal or vertical plane.
2. In fiber optics, the relative power distribution at the output of a fiber or active device as a function of position or… (Read More →)

The resistance that, if inserted in place of an antenna, would consume the same amount of power that is radiated by the antenna.

The diversion of radiation (thermal, electromagnetic, or nuclear) from its original path as a result of interaction or collisions with atoms, molecules, or larger particles in the atmosphere or other media between the source of radiation (e.g., a nuclear explosion) and a point some distance away. As a result of scattering, radiation (especially gamma rays and neutrons) will be received… (Read More →)

Measures to defend against TEMPEST attacks [CESG].

An optical fiber made with core and cladding materials that recover, within a specified period of time, a specified percentage of their intrinsic transparency after darkening from exposure to a radiation pulse.

Acronym for radar intelligence.