Abstract: Compact microwave and millimeter wave radars operating at 77 GHz and having resolution of no less than 3.2 meters at a distance of 100 meters. The exemplary dimensions of the radars are 145 millimeters in diameter and 100 or 85 millimeters long. The antenna of the radars employs folded optic design, with the actual focal length of the radar being less than that of the lens in the antenna alone.

Abstract: A system for landing aircraft during low visibility includes a number of millimeter wave sources in or near the runway light housings radiating millimeter wave beams along the runway. An airborne millimeter wave camera includes a millimeter wave lens that focuses the image of the millimeter wave sources upon a hemispherical detector array that provides signals processed to create an image of the millimeter wave sources corresponding substantially to the visible image perceived by a landing pilot when observing the runway light pattern during good visibility conditions.