等离子体对高功率微波的防护(4)

第1期 杨耿等：等离子体对高功率微波的防护

表3 实验结果

测量条件

接收端 微波 信号值/μV 衰减量/dB

93

参考文献:

95 0 32 9.5 23 12.3 4.5 26.5

收、发喇叭间不放置任何物质 收、发喇叭间有一层25mm的等离子体 收、发喇叭间有一层50mm的等离子体 收、发喇叭间有两层厚度分别为25mm、 50mm的等离子体

5 结论

随着定向能武器的不断发展，高功率微波对电子设备的破坏已经引起各国广泛地关注。由于航天环境的特殊性，常规的防护手段往往难以达到卫星电子设备所需的防护要求。本文提出的多层等离子体防护结构对电磁波的反射和吸收效应，能使透射进入工作设备的微波功率低于干扰或破坏阈值。 当等离子体频率为30GHz时，图1所示的防护结构会反射频率低于30GHz的电磁波，频率小于30GHz的高功率微波武器不能对防护设备造成危害。对于频率处于31～80GHz间的高功率微波武器，计算结果表明：电磁波透射过防护结构后的透射功率和入射功率的比值在0.3%～2.7%之间，防护结构对不同频率的电磁波防护效果不一样。从表1中可以看出装置对频率在31～80GHz之间的微波武器的最小防护距离可达5km左右。

验证性的实验表明，增加等离子体层数比增加等离子体厚度对电磁波的衰减效果更明显。

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Protection against high power microwave using plasma

YANG Geng, TAN Ji-chun, SHENG Ding-yi, YANG Yu-chuan

(Science college, National University of Defense Technology, Changsha 410073)

Abstract: Protection against high power microwave using plasma was proposed. A reflection/absorption sandwich model of “medium slab-plasma slab-medium slab-plasma slab” was established, where the thickness for the un-magnetized uniform plasma is 50mm, the plasma frequency 30GHz, and collision frequency 70GHz. Then the transmitted power of electromagnetic wave and the minimal protecting-distance of protector were calculated. The results show that for a microwave source with 10GW power, 100ns pulse width, 100m2 antenna area (with efficiency of 50%), the emitted microwave will be reflected when the frequency is less than 30GHz; or the minimal protecting-distance of protector is about 5km when the frequency is within 31～80GHz.

Key words: HPM; Plasma; Transmitted power; Protection