A blackout communication method based on parity-time symmetry gain metamaterials

During the reentry of hypersonic vehicles, the plasma sheath enveloping the vehicles causes attenuation of communication signals, which threatens vehicle safety. In this paper, the scattering matrix method is adopted to investigate the electromagnetic wave transmission characteristics in the composite structure of Parity-Time (PT) symmetric gain metamaterial and strongly collisional, high-density, inhomogeneous plasma sheath. It is found that the gain metamaterial applied to the inner wall of the vehicle can effectively compensate for the signal loss caused by the plasma sheath, while the effective communication bandwidth of electromagnetic waves is expanded, providing a new idea for maintaining reliable communication throughout the flight.