A double-slot radar fence for increased clutter suppression

A technique of edge treatment for radar fences has been developed to provide greater suppression of radar clutter return than can be obtained with a simple straight-edge blocking fence. The technique incorporates two slots in proximity to, and parallel with, the upper edge of the fence. This configuration reduces the amplitude of the diffracted fields incident on the antenna aperture, and also provides an optimum distribution of these fields so as to result in minimum reception of the diffracted signal. Calculations show that a significant improvement is obtained over the performance of a straight-edge fence of the same maximum height as a double-slot fence. A program of measurements of the double-slot fence has been conducted at millimeter wavelengths, and the results have shown excellent agreement with the calculations. For a single elevation angle of clutter return, the double-slot fence has a measured two-way suppression of 64 dB, compared with 28 dB for the straight-edge fence.