一种用于微波凝视成像的等离子体调制器

Design of A Plasma Modulator for Microwave Staring Imaging

文章介绍了一种新颖的用于新体制微波凝视成像雷达的关键器件等离子体调制器。文章将从等离子体约束腔、射频激励接口以及等离子体气压气氛配比三个部分进行专门的原理分析与研究设计,并搭建实测平台对等离子体调制器进行性能测试。文章独创地选用具有大偏转角特性的圆柱体结构对等离子体进行赋形,利用等离子体激励能量与电磁波偏转角之间的非线性关系来实现对雷达来波信号的非线性调制。采用新颖的串联谐振式电容耦合激励结构突破射频激励冷等离子体工程应用中现有技术瓶颈,大大降低了常规冷等离子体激励与维持过程中的耗能。通过计算调整用于激励出等离子体的气体压强、气氛配比与均匀度,大大增加偏转角极值,既而在激励功率步长与最大值一定的情况下提高等离子体调制器各调制态之间的隔离度。经过实验测试,本论文研制的等离子体调制器可实现在等离子体0~500w激励功率时,对X波段雷达来波信号0^-8.1d Bm的衰减调制。

this paper introduces a novel key component plasma modulator for microwave staring imaging, and will respectively explain the special analysis and research design of the RF plasma constraint cavity, incentive interface and atmosphere＇s pressure and ratio,and build a test platform for plasma modulator＇s performance testing. This paper chose original cylinder structure with large deflection Angle characteristics to form plasma so that using the nonlinear relationship between the plasma excitation energy and electromagnetic wave deflection angle to realize nonlinear modulation. This paper also invents a novel series resonant capacitance coupling incentive structure which breaks through the RF excitation bottleneck existing in engineering application of cold plasma technology and reduces the conventional energy consumption in the process of cold plasma incentive and maintain greatly. By adjusting the pressure, composition, ratio and uniformity of gas used to inspire plasma, we can increase the maximum Angle of deflection, then under the firm condition of exciting power＇s step length and the maximum value, it should increase plasma modulator＇s isolation among the modulation modes. Through experimental tests, the plasma modulator this paper develops can realize Ku band radar wave signal attenuation of 0 ^-8.1 d Bm, while the plasma exciting power of 0 ~ 500 w.