The attenuation due to atmosphere is given by
(Eq. 208)
where:
linear attenuation due to dry air (oxygen) in dB/km
linear attenuation in dB/km due to water as function
of the water concentration in g/m³, default value: 3 g/m³
Both terms can be approximated by the following equations according to ITU-R Rec. P.676-1:
- Attenuation due to water :
(Eq. 209)
for f < 350 GHz
- Attenuation due to oxygen :
f<= 57 GHz (Eq. 210)
57 < f <= 60 GHz
60 <f <= 63 GHz
for f> 63 GHz
Note: For simplification a linear interpolation between 57 and 63 GHz is used. The maximum is 15 dB/km for 60 GHz.