Study of Terahertz Wave Propagation in Realistic Plasma Sheath for the Whole Reentry Process

Terahertz (THz) communication has always been considered as a potential solution for "communication blackout" during aircraft reentry. In this article, the propagation characteristics of the THz wave in the realistic plasma sheath during the whole reentry process are studied by solving the fluid model and the THz transmission model. As a result, the electron number density and collision frequency decrease with the increase of reentry height and antenna position. And the attenuation of the THz wave decreases with the increase of the electromagnetic (EM) wave frequency, reentry height, and antenna position. Finally, two THz communication schemes to mitigate or avoid the "communication blackout" problem for the whole reentry process were discussed. One is for uncertain antenna position and reentry height, selecting EM waves with a frequency above 0.35 THz for communication. The other is to install the antenna near the bottom of the vehicle (L = - 1.0 m in this article) with a wave frequency above 0.12 THz.