螺旋波导压缩频率调制脉冲的初步研究

利用螺旋波导对频率调制脉冲进行压缩可大幅度提高脉冲峰值功率。利用所编Matlab程序对螺旋波导的色散特性进行了计算和分析，获得了波纹幅度和纵向周期长度等结构参数对其色散特性的影响规律；给出了脉冲功率压缩比的计算公式，对不同脉宽和频带宽度、不同频率调制形式的微波脉冲通过螺旋波导后的功率压缩比进行了计算和分析。计算表明：脉冲的频率调制形式对功率压缩比影响较大；相同频率调制形式下，脉冲长度越长，工作频带越宽，功率压缩比越高。为了获得尽可能高的功率压缩比，需对脉冲的频率变化方式进行调节，使其与螺旋波导色散特性匹配。同时还需要在高的功率压缩比和高的压缩效率之间做出权衡。计算得到，当注入脉冲的脉宽为40 ns、工作频带为8.8~9.5 GHz、频率调制形式与螺旋波导色散特性匹配时，功率压缩比达到了15，压缩效率约为40%。

Compression of frequency-modulated pulses by helically corrugated waveguide

The peak power of a frequency-modulated microwave pulse could be improved greatly by the compression of the helically corrugated waveguide. Firstly, the dispersion relations of the helical corrugated waveguide are calculated and analyzed using the code programmed with Matlab. The dispersion characteristics on the variation of the amplitude and period of the corrugation are obtained. Then the power compression ratios are calculated under some typical conditions. Calculation results show that: the power compression ratio is very sensitive to the format of the frequency modulation. Under the same format of frequency modulation, the power compression ratio increases with the increasing of the time width and frequency width of the input pulse. For an input pulse of 40 ns and a frequency width 0.7 GHz(from 8.8 GHz to 9.5 GHz), the format of the frequency modulation is matched to the dispersion characteristics of the helically corrugated waveguide, the power compression ratio reaches 15, and the compression efficiency is about 40%.