Q/V频段电磁波在等离子体鞘套下的传输特性

高超声速飞行器再入地面时,由于飞行器表面等离子体电子密度分布不均匀,因此从背风面向天基中继卫星传输,可避开迎风面的高电子密度,并以Q/V频段为测控频段,经中继卫星转发至地面测控站。本文以波阻抗方法为基础,分析了Q/V频段在不同等离子体参数下的传输特性,并仿真了等离子体对Q/V频段天线波束指向的影响。结果表明：Q/V频段在等离子体中穿透性更好,可在更高的等离子体电子密度和碰撞频率下保持较低的衰减值。但Q/V频段下的天线波束指向偏差较大,随着频段的提高和入射角度的减小,偏差值逐渐减小。因此,应用Q/V频段,通过中继卫星转发实现实时通信,有利于缓解再入飞行器“黑障”现象。

Q/V band waves propagation characteristics in plasma sheath

When the hypersonic aircraft re-enters the ground, due to the uneven distribution of the plasma electron density on the surface of the aircraft, the transmission from the leeward side to the space-based relay satellite can avoid the high electron density on the windward side, using the Q/V band waves as the communication band, the signal is forwarded to the ground communication station through the relay satellite. Based on the wave impedance method, this paper analyzes the transmission characteristics of the Q/V band under different plasma parameters and simulates the effect of the plasma on the antenna beam pointing in the Q/V band. The results show that the Q/V band has better penetration in the plasma and can maintain a lower attenuation value at higher plasma electron density and collision frequency. However, the antenna beam pointing deviation in the Q/V frequency band is relatively large, and the deviation value gradually decreases with the increase of the frequency band and the decrease of the incident angle. Therefore, using the Q/V band to realize real-time communication through relay satellite forwarding is conducive to alleviating the "blackout" phenomenon of re-entry aircraft.