Abstract: The radar radiates, alternately or according to a given code, left-hand and right-hand circularly or elliptically polarized signals. At the receiving end, the two orthogonal polarized components of the received signal are processed separately, and the phase shift between the two components is measured. It is determined whether this phase shift is similar to that existing at the instant of transmission between the two orthogonally polarized components which are mixed to produce the circularly or elliptically polarized signal. The similarity check is made by correlation.A desired target is indicated if there is a given similarity. Coherent signal processing is not necessary (but possible).