Analysis of antenna radiation of hypersonic vehicle with plasma sheath

The plasma sheath of the near space hypersonic vehicle has the characteristics of non-uniformity, negative dielectric constant and electrically large size. Such features pose great challenge to the existing electro-magnetic numerical methods. In this paper, the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) is used to simulate the antenna radiation of hypersonic vehicles with plasma sheath. Aiming at non-uniform characteristics and anisotropy caused by magnetization, the FE-BI-MLFMA formula with tensor dielectric constant is derived, and the system matrix is preconditioned to expedite the iterations. The plasma-coated spherical cone model with antenna mounted on different positions are simulated. The radiation patterns of different incident frequencies are calculated at different flight heights and velocities. The simulation data indicates that the plasma sheath has a smaller effect on the antenna when the frequency increases, or the antenna is deployed at the tail of the vehicle where the electron density is much lower. By adding a static strong magnetic field, the radiation performance of the antenna in the high-electron density distribution area can be improved. Besides, the radiation enhancement, pattern reversal, offset and other phenomena can be observed with this method, which can provide data support for antenna design and blackout communication of hypersonic vehicle.