subreflektor

Subreflektor is a term used to describe a secondary reflective element incorporated into a wave propagating system, positioned near or within the path of a primary reflector to influence the resulting wavefront. The concept spans optics, radio astronomy, radar, and related fields, and the exact definition can vary by discipline. In some contexts it is a generic name for any auxiliary mirror that modifies the focus or beam shape.

Designs of a subreflektor can range from a conventional curved mirror placed close to the focal region of a primary reflector to engineered metasurfaces that can tailor phase and amplitude across the aperture. In radio-frequency systems, a traditional subreflector is often part of a Cassegrain or related configuration; in optical and modern antenna contexts, active or adaptive variants may adjust their properties in real time to respond to changing conditions.

Operation typically involves intercepting a portion of the reflected wave and re-emitting it with a controlled phase front or amplitude distribution. This can sharpen focus, broaden or steer the beam, reduce sidelobes, or correct aberrations introduced by the main reflector. Subreflectors may be designed for wideband performance or tuned to a specific frequency range, and some implementations employ dynamic control to adapt to different observational goals.

Applications and context include large astronomical telescopes, satellite dish antennas, radar systems, and imaging platforms that rely on precise beam formation. The term is sometimes used as a regional spelling variant or in parallel to the more common “subreflector,” particularly in discussions of historical or theoretical designs.

See also: subreflector; Cassegrain telescope; Gregorian telescope; metasurface; phase conjugation.