Observations of the specific attenuation of millimeter waves by rain

Measurements of the attenuation rate in rain at 28.8, 57.6, and 96.1 GHz were obtained at locations in California, Colorado, and Alabama in order to study the dependence of attenuation rate on rain rate, climate, and type of rain. Both the measured data and predictions for drop-size distribution show a wide range in attenuation rates. None of the drop-size distributions are found to adequately predict attenuation for a range of millimeter-wave frequencies in any of the observation regions.