激波管等离子体中太赫兹波传输特性仿真与实验研究

Terahertz wave transmission characteristics in the plasma produced by shock tube

研究了太赫兹波在透射波窗口封闭的激波管中的等离子体中的传输特性,获得了传输衰减量随等离子体电子密度、碰撞频率、透波窗口材料以及电磁波频率的变化规律,并比较了相同条件下毫米波的传输特性.利用激波管为实验平台模拟产生高速飞行器等离子体,开展了太赫兹波在等离子体中传输特性实验.结果表明,太赫兹波在相同电子密度和碰撞频率的等离子体中衰减量比毫米波小得多;随着等离子体碰撞频率的增加,太赫兹波传输衰减量先增加后减小,透波窗口增加了太赫兹波的传输衰减;随着窗口材料的介电常数增加,太赫兹波反射率增加,太赫兹波传输衰减曲线出现周期性振荡,振荡周期约5 GHz;太赫兹波通信可能作为一种解决再入飞行器黑障问题的有效技术途径.

The transmission characteristics of millimeter wave and terahertz wave in the nonmagnetic collisional plasma were investigated to meet the need of reentry aero-craft communication. The laws of electromagnetic wave transmission attenuation dependent on electron density, collision frequency, dielectric coefficient change of the antenna window material and electron frequency were obtained. The terahertz wave transmission attenuation （TWTA） is more fader than mil- limeter wave transmission attenuation （MWTA） in the same plasma. Both TWTA and MWTA in the plasma are at first enhanced and then impeded with increase of collision frequency of the plasma. With the increase of the dielectric coeffi- cient of the antenna window material, MWTW is uplifted and there is a periodic oscillation in the MWTA curve, the periods of which is 5 GHz. TWTA experiment was carried out on the shock tube. The results are in agreement with the calculation. Terahertz wave can be likely used as the media to resolve communications blackout on reentry aero-craft.