Antenna terms, and definitions

Anechoic Chamber: A room or enclosure designed to absorb sound and stop reflections.

Angle of Incidence: The acute angle at which a wave of energy strikes an object or penetrates a layer of the atmosphere or ionosphere. The angle between the incident wave and the normal. The angle between an incident ray and the normal to a reflecting or refracting surface.

Anisotropic: .The property of a radiator that allows it to emit strong radiation in one direction.

Antenna: A device used to radiate or receive waves [electromagnetic energy] through space, generally RF energy. A conductor or set of conductors used to radiate RF energy into space or to collect RF energy from space or to do both. Antenna Manufacturers.

TV Antenna

Antenna Array: A grouping of antennas. See graphic to the right. An assembly of antenna elements with dimensions, spacing, and illumination sequence such that the fields for the individual elements combine to produce a maximum intensity in a particular direction and minimum field intensities in other directions. Also refer to Phased Array Antenna.

Antenna bandwidth: The frequency range over which a given antenna will accept signals. A range of frequencies over which the impedance of an antenna does not change sufficiently to effect the signal.

Antenna Cores. A ferrite core used as a radio antenna.

Antenna Coupler: A device used for impedance matching between an antenna and a transmitter or receiver.

Antenna Dissipative Loss: A power loss resulting from changes in the measurable impedance of a practical antenna from a value theoretically calculated for a perfect antenna.

Antenna Effective Area: The functionally equivalent area from which an antenna directed toward the source of the received signal gathers or absorbs the energy of an incident electromagnetic wave.

Antenna Efficiency: The ratio of the total radiated power to the total input power.

Antenna Electrical Beam Tilt: The shaping of the radiation pattern in the vertical plane of a transmitting antenna by electrical means so that maximum radiation occurs at an angle below the horizontal plane.

Antenna feed: Means by which power is transferred to and from the antenna and the connecting transmission line.

Antenna gain: The effectiveness of a directional antenna as compared to a standard non-direction antenna. It is usually expressed as the ratio in decibels of standard antenna input power to directional antenna input power that will produce the same field strength in the desired direction. For a receiving antenna, the ratio of signal power values produced at the receiver input terminals is used. The more directional an antenna is, the higher is its gain. The ratio of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength at the same distance.

Antenna Lobe: A three-dimensional section of the radiation pattern of a directional antenna, bounded by one or more cones of nulls or by regions of diminished irradiance.

Antenna Matching: The process of adjusting impedance so that the input impedance of an antenna equals or approximates the characteristic impedance of its transmission line over a specified range of frequencies.

Antenna Pattern: See Radiation Pattern.

Antenna Pedestal. A structure supporting an antenna. Refer to Companies producing Antenna Pedestals.

Antenna Power. Text in review.

Antenna Reflector. See reflector.

Antenna Tower: Any type of antenna placed atop a tower, which is used to rise the antenna above the ground. Also refer to manufacturers of Antenna Towers [includes a graphic of a UHF antenna tower].

Antenna Under Test. [AUT]. Related; System Test Abbreviations.

Antenna Wire: A wire used to form an antenna: examples; 12 AWG bare, copper-clad steel, 7 stranded wire, 7 strands of 20 AWG silicon bronze wire concentric stranded. Related link Table of Wire Gauges [does not cover steel wire].