Frequency-Dependent Atmospheric Radio Refractivity Models for THz band

Atmospheric radio refractivity has an obviously impact on the signal transmission path and communication group delay effect. In this paper, we first analysis existing radio refractivity models and establish the reference refractivity based on molecular response theory (MRT) and empirical results. Then, two frequency-dependent atmospheric radio refractivity models are proposed respectively for sub-500 band and THz band, which can avoid complex calculations in MRT. Taking the established reference refractivity as the benchmark, the numerical results show that the mean absolute errors of the two proposed models are almost less than 0.3 and 0.4 in sub-500 GHz and THz bands, respectively. This work will contribute to the research of THz communication and THz weather radar, etc.