RADAR IMAGING.

The report describes experiments with an electronically scanned X-band array employed as the receiving antenna of an imaging radar. Planar and solid targets were uniformly illuminated from a separate transmitting antenna and the resulting scatter was intercepted by 128 horn antennas unequally spaced over a 9 foot aperture. The 128 received signals were processed electronically to provide a complete scan of a 30 deg x 30 deg field every 10 milliseconds. Target images originally recorded on motion picture film are presented for varying conditions of illumination monochromatic and FM and target motion translation and rotation. The design, construction, and performance of the experimental radar are also discussed. A major limitation of this radar is the interference caused by sidelobes which are an inevitable result of incomplete spatial sampling limited number of array elements. A new type of radar is suggested for imaging consisting of linear transmit and receive arrays which are orthogonal to each other a system of this type will permit a substantial reduction in sidelobe noise without increasing the number of antenna elements. The cost of implementing such a system for satellite identification is estimated. Author