An investigation on the propagation characteristics of Terahertz wave in Kashgar

The broadband and high rate advantages of Terahertz (THz) wave communication attract tremendous attention of many researchers, and the study of the THz sources and detectors are more popular in recent years than previous. The study on the propagation characteristics of THz wave in troposphere is relatively rare, and it is necessary due to the rapid development of the THz devices. The content of water vapor and the oxygen in the tropospheric atmosphere are the main factors that influence the absorption of THz wave because of the resonance of THz wave with the water and oxygen molecules, and as a result, the propagation characteristics of THz wave in different climate zones can be very different. THz wave propagation characteristics in Kashgar, Xinjiang, China are investigated and compared to that of Qingdao herein, and the results show that Kashgar is more suitable for THz earth-space communication owing to its drier atmosphere. The propagation characteristics are analyzed along a path of 14km through troposphere on earth-space links in zenith in Kashgar. The attenuation of 0.14THz wave is as small as 0.48 dB in winter and 1.5 dB in summer, both of the attenuation are much smaller than that of surface attenuation, and the similar results are obtained for 0.22 THz and 0.34THz wave, while all of frequencies used here are window frequencies in atmosphere. The analysis above offers theory basis for the high efficiency communication system. The effect of elevation angle on the tropospheric propagation of THz wave is also calculated and analyzed, while the results show that the bigger the elevation angle, the more suitable for the communication applications.