Improved algorithms for the determination of specific attenuation at sea level by dry air and water vapor, in the frequency range 1–350 GHz

Abstract

This paper presents new algorithms for the determination of specific attenuation by dry air and water vapor, at sea level, in the frequency range from 1 to 350 GHz. The algorithms are shown to be an improvement on those recommended by the International Radio Consultative Committee (CCIR), by including the effects of high‐frequency rotational transitions in oxygen, pressure‐induced nitrogen absorption (important for ƒ > 150 GHz) and a quadratic dependence of attenuation on water‐vapor density. Simple scaling factors are given to include the effects of temperature dependence of attenuation, over the range −20°C to 40°C.