天线阻抗特性对开关振荡器输出脉冲的影响

以单锥天线和螺旋天线作为开关振荡器辐射天线为例，采用等效电路模型和商业电磁仿真软件，分别对天线末端电压振荡信号和辐射电场脉冲进行了研究。研究结果表明:采用行波天线或者电长度与振荡器一致的振子天线作为辐射天线，都能够产生中心频率与振荡器本征频率一致的电磁脉冲信号；但采用振子天线时，振荡信号持续时间较短(Q值较低)，频谱上能量较分散，带宽较宽，而采用行波天线则脉冲持续时间较长(Q值较高)，频谱上能量较集中，带宽较窄。

Influences of impedance characteristics of radiating antenna on output pulse of switched oscillators

The oscillating voltage signal on the antenna terminal and the electric field at far-field district are analyzed by equivalent circuit and commercial electromagnetic software, respectively, taking monocone and helical antennas for examples. It is demonstrated that the center frequencies of the generated electromagnetic pulses coincide with the characteristic frequency of the switched oscillator adopting either element antenna with the same electrical length as the switched oscillator (electrical length matched) or traveling wave antenna. However, there are some differences between them. For an element antenna (electrical length matched), the duration of the output pulse is relatively short with low Q value and the energy disperses in a relatively wide band in frequency domain. On the contrary, the duration of the output pulse is relatively long with high Q value and the energy concentrates on a relatively narrow band in frequency domain for element antenna. This result helps to understand the generation of high power electromagnetic pulse utilizing switched oscillator and has practical significance to the antenna choice in different application occasions.