Measurments of attenuation and refractive dispersion due to atmospheric water vapor at 80 and 240 GHz

Field line-of-sight propagation experiments were made at 80 and 240 GHz on a horizontal path of 810 m. The measured attenuations showed quadratic dependences on atmospheric water vapor density, and absorptions in excess of theoretical predictions were observed at both frequencies, while the measured refractive dispersion between these two frequencies showed a linear dependence on water vapor density and was in good agreement with theoretical prediction. Liebe's model for water vapor attenuation including empirical continuum absorption is confirmed to be effective for 80 and 240 GHz.