Electromagnetic Scattering from Spheres with Sizes Comparable to the Wavelength

Abstract

By using suitably defined logarithmic derivative functions and the recurrence formulas due to Infeld, the problem of obtaining numerical answers for the scattering of a plane electromagnetic wave by a sphere can be simplified. This is particularly true if the sphere has a complex index of refraction. The nature of these logarithmic derivative functions is shown for one special case involving water spheres. Experimental results are given for the back‐scattering cross sections of water spheres in the electrical size region 0.74≤2πa/λ≤5.90. These results were obtained at a wavelength of 16.230 cm using the standing‐wave method of measurement. It is believed that these were the first laboratory measurements of the back‐scattering cross section made on individual water spheres in this critical size region. Comparison is made between the experimental and theoretical results.