directional antenna - an antenna that transmits or receives signals only in a narrow angle

microwave radar, radar, radio detection and ranging, radiolocation - measuring instrument in which the echo of a pulse of microwave radiation is used to detect and locate distant objects

radio reflector, radio telescope - astronomical telescope that picks up electromagnetic radiations in the radio-frequency range from extra-terrestrial sources

scanner - a radar dish that rotates or oscillates in order to scan a broad area