大口径天线短脉冲微波辐射特性

Microwave radiation characteristics of large-aperture antenna excited by short pulses

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0.5ns)的微波激励脉冲、接收动态范围大于52dB。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 chan-ging microwave pulse-width;it was found that radiation waveforms deviated from the principal axis in different angles could pres-ent pulse widening and amplitude decreasing,the greater the angle deviated,the more obvious the phenomenon could be.