Radar Antennas

of military necessity. This development will continue, for radar has increasing applications in a peacetime world. In this paper we will discuss an indispensable part of radar--the antenna. In a radar system the antenna function is two-fold. It both projects into space each transmitted radar pulse, and collects from space each received reflected signal. Usually but not always a single antenna performs both functions. The effectiveness of a radar is influenced decisively by the nature and quality of its antenna. The greatest range at which the radar can detect a target, the accuracy with which the direction to the target can be determined and the degree with which the target can be discriminated from its background or other targets all depend to a large extent on electrical properties of the antenna. The angular sector which the ai#enna can mechanically or electrically scan is the sector from which the radar can provide information. The scanning rate determines the frequency with which a tactical or navigational situation can be examined.