RADAR(RAdio Detection And Ranging) is an all weather day-and-night surveillance sensor to acquire the target information using radio waves.

Radar is divided into ground-based, ship- and air-borne radars. Radar antennas are mainly classified into reflectors and active or passive phased array antennas. With the rapid development of solid-state device technology, several radar systems which apply to the active phased array are being developed. In addition, the radar in accordance with its operational purposes can be classified into surveillance radar, tracking radar, and multi-functional radar. A variety of radar have been developing in the country.