Antenna feed for scan-with-compensation tracking

摘要

An antenna feed for decreasing the scan modulation of the radiated signal of a radar which tracks by the method known as scan-with-compensation. The antenna feed is comprised of a coaxial line fed dipole located on the axis of a circular waveguide for radiating a single on-axis unmodulated pencil-beam during transmission. The antenna feed further comprises two parallel radiators located equally distant and on opposite sides of the transmitting circular waveguide radiator and functions during reception only. Rectangular waveguides connect the two parallel radiators with the central radiator so as to give rise to orthogonal signals in the central radiator upon reception of echo signals. An ATR tube connects the dipole to the central axial waveguide during transmission and isolates it during reception. The radiating dipole is mounted so as to remain fixed while the central circular waveguide and the two parallel reception waveguides rotate during scanning.