Modellversuche zur elektromagnetischen Rückstrahlortung (RADAR) mit Ultraschallwellen (SONAR)

The following results were obtained from model experiments for radar camouflage with ultrasonic waves (SONAR) with 2.5 mm wavelength:

The radar screen picture is essentially composed of signals reflected optically from plane surfaces and of scatter signals from edges. The level of scatter signals from edges was at least 30 dB below that of optical reflections. The scattered wave from an edge is only slightly changed when the adjoining surface is covered with absorbers.

In order to lower the level of scatter signals from edges by about 10 to 20 dB down to the noise level it is sufficient to tooth the edges over a distance equal to several wavelengths.

Screen pictures of model villages are given. Measurements of the back scattering of spheres, cylinders and circular disks of various cross-sectional area were used for calibrating the apparatus.