telecommunication Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

s and

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

engineering, the antenna boresight is the axis of maximum gain (maximum radiated power) of a directional antenna. For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial-fed

dish antenna A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or p ...

s, the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna

radiation pattern In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the ''directional'' (angular) dependence of the strength of the radio waves from the antenna or other source.Constantine A. Balanis: " ...

(the main lobe) is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antennas can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions (multiple boresights). The term ''boresight'' came from

high-gain antenna A directional antenna or beam antenna is an antenna that radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction ...

s such as parabolic dishes, which produce narrow, pencil-shaped beams which are difficult to aim accurately at a distant receiving antenna. These often are equipped with optical boresights to assist in aiming.

References

Antennas (radio) {{telecomm-stub