A17.5.2 Attenuation due to atmosphere

The attenuation due to atmosphere is given by

  (Eq. 217)

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. 218)

            for f < 350 GHz

• Attenuation due to oxygen :

(Eq. 219)

     f<=   57 GHz 

                                                   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.