abstract
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A digital signal processor, operating at baseband, is described for the scanning of a Mills' cross array antenna. The processor uses time modulation to scan the pencil beam produced by the array in a raster-like fashion over the prescribed sector. The scheme uses within-pulse scanning in order to avoid the loss of power in the fan beams outside the area covered by the pencil beam. This processor provides flexibility in applying different types of aperture distribution to modify the side-lobe structure of the antenna pattern. It provides a simple means for changing the scanning rate of the array.
The different types of scanning technique are reviewed briefly. A detailed mathematical analysis of time modulation scanning technique is presented. Experimental results are included to demonstrate the practical feasibility of the digital baseband processor for scanning the Mills' cross array antenna along prescribed look directions inside the visible region of interest.