超宽带Cassegrain双反射面天线研究

 为了减小馈线损耗和方便天线旋转，设计了超宽带Cassegrain双反射面天线系统。采用FEKO数值模拟软件在0.2~1.5 GHz频率范围内模拟了不同副反射面直径的4.5 m双反射面天线(焦径比为0.4)的辐射增益，并与相同口径和焦径比的前馈式反射面天线进行了比较。模拟结果表明:当双曲副反射面直径为70 cm，焦距为22.5 cm时，在0.2~1.0 GHz频率范围内，双反射面天线增益比前馈式抛物面天线高1～2 dB；在1.1～1.5 GHz频率范围内，双反射面天线增益比前馈式抛物面天线小1～2 dB。选择直径为70 cm、焦距为22.5 cm的双曲副面与TEM喇叭和4.5 m抛物面组成双反射面天线系统，分别用960 ps和3 ns脉宽的单极脉冲源对天线进行了实验研究。实验结果表明:用960 ps和3 ns脉宽的单极脉冲激励，Cassegrain双反射面天线在70 m轴上远场辐射场波形峰峰值分别为前馈式反射面天线的158%和162%。

Cassegrain dual reflector antenna for UWB high power microwave

A Cassegrain dual reflector antenna which consists of a TEM horn,a hyperbolical subreflector and a parabolic reflector,was developed to radiate high power UWB microwave.The Cassegrain dual reflector is formed by a 4.5 m parabolic reflector(the ratio of focal length to diameter is 0.4) and a 70 cm hyperbolical subreflector(focal length is 22.5 cm).The size and the F/D parameter of the parabolic single reflector antenna in experiment are the same as that of the dual reflector antenna.The gain of the Cassegrain dual reflector antenna and the parabolic single reflector antenna were simulated by FEKO program.The gain of the Cassegrain dual reflector is 1~2 dB higher than that of the parabolic single reflector at the frequency band between 0.2 GHz to 1.0 GHz,while the gain is 1~2 dB lower between 1.1 GHz to 1.5 GHz.Excited by a 960 ps pulse and a 3 ns pulse,the peak-peak value of radiation field waveform at 70 m on boresight of Cassegrain reflector antenna is 158% and 162% of that of the parabolic single antenna,respectively.