Numerical Simulation of Interaction between Microwave and Plasma Flow Field

When a hypersonic vehicle re-enters the atmosphere, it compresses the surrounding flow field at high speed and ionizes the gas molecules at high temperature, generating a plasma sheath on the surface of the vehicle, which makes it difficult to transmit electromagnetic waves. To solve the problem of the interaction between microwave and plasma flow field, a model of plasma sheath is established based on the flight test data of a typical blunt cone hypersonic vehicle and CST software. The influence of plasma oscillation frequency on the attenuation characteristics of microwave propagation is analyzed through numerical calculations. The simulation shows that when the plasma oscillation frequency is $\mathbf{4 4} \mathbf{~ G H z}$, the propagation constant $S_{21}\lt-30$ dB in the plasma when the microwave frequency is smaller than the plasma oscillation frequency, and $S_{21}$ tends to 0 when the microwave frequency is larger than the plasma oscillation frequency, which indicates that the plasma has a greater attenuation effect on the microwave band lower than the plasma oscillation frequency only.