为了开展大口径天线短脉冲微波辐射特性研究, 建立了一套大口径天线微波短脉冲特性测试系统。该系统可产生快上升沿、脉冲可调(脉宽最短可到0.5 ns)的微波激励脉冲、接收动态范围大于52 dB。利用该测试系统进行实验, 获得了不同微波激励脉冲宽度条件下, 天线方向图和辐射场波形脉冲宽度变化曲线。测试结果表明: 在天线远场距离处, 改变微波激励脉冲宽度, 对天线主轴辐射场波形基本无影响; 而在偏离主轴处, 辐射场波形会出现不同程度的脉冲展宽及幅值减小等波形畸变现象, 偏离主轴角度越大, 微波激励脉冲宽度越小, 畸变越明显。

A new type of test system has been designed for the research on microwave radiation characteristics of large-aperture antenna excited by short pulses. The system is made of a pulse-width tuning microwave source (the shortest pulse-width is 0.5 ns) and a receiving system whose dynamic range is up to 52 dB. Based on such test system, the changing curve of antenna pattern and the pulse-width of antenna’s radiation field waveform were obtained under the condition of different microwave pulse-width. The results show that in far field, there is no significant influence on the radiation waveform in the principal axis, by changing microwave pulse-width; it was found that radiation waveforms deviated from the principal axis in different angles could present pulse widening and amplitude decreasing, the greater the angle deviated, the more obvious the phenomenon could be.