GB1304256A - - Google Patents

Abstract

1304256 Radar; aerials SIEMENS AG 23 June 1970 [24 June 1969] 30361/70 Headings H4A and H4D A radar system comprises a directional aerial array, the individual elements of which are fed via adjustable phase shift devices, whose maximum phase difference in the operating frequency band does not exceed 360 degrees, and means to transmit simultaneously from said array a plurality of separate radar signals having different carrier frequencies. As described, an array arrangement 10 comprises two planar directional arrays, in each of which 25 dipoles are arranged on a respective side of a box 18 having radiation opaque partition walls. The near-side array is illuminated by a cluster of four horn radiators 11 to 14 each of which is supplied with a radar signal of different frequency. Said radar signals are produced by separate transmitters S1 to S4, which are connected through T/R switches SE1 to SE4 to the horns. Echo signals received by the horns are coupled through the T/R switches to receivers E1 to E4. Each dipole 15 of the nearside array is connected through an adjustable phase shift device 16, which may be electrically controlled, to an associated dipole 17 of the far-side array. The values of phase shift provided by the devices 16 are arranged so that a curved wave front received from a horn by the nearside array is transmitted by the far-side array as a flat wave front, directed as required in azimuth and in elevation. The axes of the horns are relatively tilted and because of these, and of their different frequencies of operation, four beams are radiated in different directions from the far side array. The individual radar signals are preferably pulsed, and they may be of different powers. The signals may be noisemodulated, and analysis of the echo signals may utilize correlation detection techniques.