94 GHz bistatic scattering in rain

This paper presents measurements of bistatic scattering of electromagnetic waves by rain at 94 GHz in vertical polarization. The experiment was done using transmitting and receiving rotating antennas of 312 m distance. Both antennas could be rotated independently in the horizontal plane enabling the measurement of bistatic scattering angles from -120° to +120°. The raindrop size distributions were measured by a distrometer located close to the propagation path. Since narrow beam antennas were employed and the path length was relatively short, the scattering volume was small and the rain statistics could be assumed homogeneous over the scattering volume. We show that computations using the first order of multiple scattering hypothesis and Mie theory for spherical drops are in good agreement with measured experimental values