Multidimensional radar imaging with a polarimetric focused-beam scatterometer

A small millimeter-wave, polarimetric, focused-beam radar scatterometer known as the flashlight radar (FLR) has been developed. The FLR has three-dimensional resolution capability. It obtains high angle-angle resolution from a focused horn-lens antenna that produces a beam spot size of 4.6 in. in diameter at a distance of 10 ft from the radar. Six-inch range resolution is achieved from its 1-GHz swept bandwidth. The scatterometer operates at a center frequency of 35 GHz and uses the FM-CW method. It has been used to look at small targets and materials, and to make three-dimensional radar images of large objects. The radar output can be processed to simulate larger beamwidths, for example, or to give differing resolutions, or one of its three dimensions can be collapsed so as to compare an existing synthetic aperture radar image with that obtained from the scatterometer. The authors outline the FLR design, calibration, and processing. Also presented are samples of processed radar data obtained with the instrument.<>