Some Experiments on Centimeter-Wavelength Scattering by Small Obstacles

Abstract

The scattering of electromagnetic waves by small obstacles has been measured in several cases which are of interest in connection with the interpretation of radar echoes from rain and cloud formations. The measurements were made at a frequency of 3000 Mc/sec by an impedance‐bridge technique, the specimens being contained in a wave guide. The results verify the theoretical relationship between the size of the scatterer and the intensity of the backscattered wave. Observations have also been made of the variation in scattering during the melting of an obstacle initially composed of ice. In this case, it was not possible to simulate exactly the conditions of large‐scale meteorological phenomena; however, the experiments demonstrate qualitatively that, as had been predicted, the power backscattered from an initially nonspherical ice particle passes through a maximum value during the transition to a water drop.