Radar Definitions and Jargon
"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
"A" to "Ang", "Anh" to Ant", "Ap" to Az"
Antenna: Any structure or device used to collect or
radiate electromagnetic waves. Antenna Dictionary
Antenna Array: 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.
Antenna Beam Width Pattern
Antenna Beamwidth: The angle, in degrees, between the half-power points (-3 dB) of an antenna beam. This angle is also nearly that between the center of the main-lobe and the first null. The angle is given for both horizontal and vertical planes unless the beam is circular. When so indicated, the term may refer to the angular width of the mainlobe between first nulls [beamwidth between first nulls (BWFN)]. See also Antenna Pattern.
Antenna Cross Talk: A measure of undesired power transfer through space from one antenna to another. Ratio of power received by one antenna to power transmitted by the other, usually expressed in decibels.
Antenna Isolation: The ratio of the power input to one antenna to the power received by the other. It can also be viewed as the insertion loss from transmit antenna input to receive antenna output to circuitry.
Antenna Lobing: Two lobes are created that overlap and intercept at -1 to -3dB. The difference between the two lobes
produces much greater spatial selectivity than provided by either lobe alone. (See also Lobe, Antenna).
Antenna Nutating: An antenna, as used in automatic-tracking radar systems, consisting of a parabolic reflector combined with a radiating element which is caused to move in a small circular orbit about the focus of the antenna with or without change of polarization. The radiation pattern is in the
form of a beam that traces out a cone centered on the reflector axis.
Antenna Pattern: A cross section of the radiating pattern (representing antenna gain or loss) in any plane that includes
the origin (source reference point) of the pattern. Both horizontal and
vertical polar plots are normally used to describe the pattern. Also, termed "polar diagram" and "radiation pattern."
Antenna, Pencil-Beam: A highly directional antenna designed that cross sections of the major lobe are approximately circular, with a narrow beamwidth.
Antenna System: Routes rf energy from the transmitter, radiates the energy into space, receives
echoes, and routes the echoes to the receiver.
Anti-Clutter Circuits: Circuits which attenuate undesired reflections to permit detection of targets otherwise obscured by such reflections.
Anti-Jamming Circuit: Electronic circuit used to minimize the effects of enemy
countermeasures, thereby permitting radar echoes to be visible on the indicator.
Anti-Transmit Receive Tube: (atr) A tube that isolates the transmitter from the antenna and
receiver. Used in conjunction with tr tube.
