The attenuation due to atmosphere is given by
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| body | ${{A}_{g}}=\left[ {{\gamma }_{O}}(f)+{{\gamma }_{w}}(\rho ,f) \right]\ d$ |
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(Eq. 217)
where:
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linear attenuation due to dry air (oxygen) in dB/km
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| body | ${{\gamma }_{w}}(\rho ,f)$ |
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linear attenuation in dB/km due to water as function
of the water concentration in g/m³,
default value: 3 g/m³...
- Attenuation due to water :
(Eq. 218)
for f < 350 GHz
- Attenuation due to oxygen :
...
(Eq. 219)
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| body | ${{\gamma }_{O}}(f)=\left[ 7.19\ \cdot {{10}^{-3}}+\frac{6.09}{{{f}^{2}}+0.227}+\frac{4.81}{{{(f-57)}^{2}}+1.50} \right]\ {{f}^{2}}\ {{10}^{-3}}$ |
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f<= 57
GHz (Eq. 219) 
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| body | ${{\gamma }_{O}}(f)=10.5+1.5\ (f-57)$ |
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57 < f <= 60
GHz 
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| body | ${{\gamma }_{O}}(f)=15+1.2\ (f-60)$ |
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60 <f <= 63 GHz | Mathinline |
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| body | ${{\gamma }_{O}}(f)=\left[ 3.79\ \cdot {{10}^{-7}}\ f+\frac{0.265}{{{(f-63)}^{2}}+1.59}+\frac{0.028}{{{(f-118)}^{2}}+1.47} \right]\ {{(f+198)}^{2}}\ {{10}^{-3}}$ |
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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.