轴向反馈式虚阴极振荡器辐射微波模式的远场测定

 采用远场测量法测量了虚阴极振荡器波导口的微波辐射方向图及虚阴极振荡器波导口处接上TM₀₁-TE₁₁模式转换器时的微波辐射方向图，接收喇叭口面与微波辐射口之间的距离为1.00 m，满足远场条件。结果表明：两种情况下的辐射主模式分别为TM₀₁模式和TE₁₁模式，从而证实了在实验装置轴对称的条件下，轴向虚阴极振荡器的微波辐射主模式确为理论所预期的TM₂模式。对辐射模式的分析表明，TM₀₁模式纯度约为90%，TE₁₁模式的辐射功率为TM₀₁模式的5%左右；TE₂₁，TE₀₁和TM₁₁模式三者的总辐射功率较TM₀₁模式低一个量级以上，微波辐射功率大于300 MW，辐射频率为4.6 GHz左右，微波脉宽大于40 ns。

Far-field measurement of microwave mode radiated by an axial feedback vircator

Far-field measurement is carried out for the radiation patterns from the opening of the vircator and the opening of the TM_~01 -TE_~11 converter connected with the vircator, with the distance being 1.00 m between the openings of the receiving horn and that of the microwave radiation. The results show that the main modes of the radiation are the TM_~01 and TE_~11 , respectively. This confirms the theoretical expectation of the TM_~01 mian mode for the microwave generated by an axial feedback vircator with experimentally cylindrical symmetry. Modes analysis shows that the radiated microwave has its main mode of the TM_~01 with its mode-purity of about 90%, and that the radiation power exceeds 300 MW, with the power of the TE_~11 mode being approximately 5% of that of the TM_~01 mode, and the total power of the TE_~21 , TE_~01 and TM_~11 modes being less than an order of magnitude of that of the TM_~01 mode. The radiation frequency is about 4.6 GHz and its pulse width is above 40 ns, experimentally.