Feed horn

Feed horn with concentric rings (left) and LNB (right) on a Hughes DirecWay home satellite dish.
An LNBF (LNB with integrated feed horn) that has been cut into two. Visible is the scalar horn antenna (the funnel with concentric rings), which couples the microwave beam into a short waveguide (the tube connecting the feed horn to the LNB electronics part of the LNBF).
Feed horn (right) on a military radar antenna. The feed horn must be shaped to produce a radiation pattern tailored to adequately illuminate the reflector.

A feed horn (or feedhorn) is a small horn antenna used to couple a waveguide to e.g. a parabolic dish antenna or offset dish antenna for reception or transmission of microwaves. A typical application is the use for satellite television reception with a satellite dish. In that case the feed horn can either be a separate part used together with e.g. a "low-noise block downconverter" (LNB), or more typically today is integrated into a "low-noise block feedhorn" (LNBF).