折叠型平板Blumlein线的特征阻抗

Characteristic resistance of folded Blumlein line

计算了折叠型平板Blumlein线平板部分的特征阻抗;对折叠部分的特征阻抗,采用基于单位长度电感和电容概念的方法进行了理论分析,并基于等效能量概念进行了数值计算,两种方法计算得到的特征阻抗值基本一致,而且与平板部分的阻抗值相差不大。使用电磁场模拟软件计算模拟了不同折叠内半径的折叠部分的电场分布,从而确定了最佳折叠半径;采用等效电路分析方法对匹配负载上得到的电压电流波形进行了模拟。设计并制作了折叠半径为10 mm,耐压500 kV,延时100 ns,特征阻抗为4.773Ω的折叠型平板Blum-lein线。在二极管匹配负载上得到幅值为500 kV,脉宽100 ns的电压波形和幅值为50 kA的实验电流波形。结果表明平板部分和折叠部分的特征阻抗的差值对实验波形几乎没有影响。

The characteristic resistances of the folded parts of Blumlein line were theoretically calculated by a method based on the unit capacitance and inductance concept, and were numerically calculated based on the equivalent energy. The results of these two methods are nearly accordant and show the characteristic resistance of the folded parts is nearly the same as that of the parallel parts. The electric field intensity distributions of folded parts with different inner radii were simulated, which gives an optimized inner radius of 10 mm. The output waveforms on the match load were also simulated by means of equivalent electric circuit. According to the results of the theoretical analysis and simulation, a Blumlein line of folded parallel-plates configuration with output voltage of 500 kV, pulse duration of 100 ns, characteristic impedance of 4. 773 Ω was designed, manufactured and verified as well. The difference of characteristic resistance between parallel parts and folded parts have little influence on the experimental waveforms.