Near-field spot-focused microwave sensing for the detection of buried land-mines

The most promising technique to date for detecting buried mines, ultra-wide-band ground-penetrating radar, is still quite limited as regards: depth of penetration of attenuating ground; false alarm rate; missed detections need for skilled operation and interpretation; and area covered per unit time. We hope to achieve significant improvements in all these respects by the use of near-field focused radar. Spot focusing of the transmitted and received radiation enhances the resolution, and the focusing convergence gain counterbalances the path-loss, in a highly attenuating medium such as moist soil. Furthermore, unwanted reflecting objects are unfocused, thus substantially reducing obscuration of wanted targets by “clutter”. This is of special importance in an attenuating medium, where a shorter unwanted path would benefit from reduced path loss. These gains in sensitivity should also enable us to cope with the extra attenuation of a somewhat shorter wavelength, thus improving the compromise between resolution and depth of penetration. Several novel variants of this technique are considered