阻抗匹配条件下磁控管的注入锁频

Injection-locking of magnetrons with matched impedance

单只磁控管输出功率不能满足大规模工业应用,需要对多只磁控管进行相干功率合成.为解决普通磁控管相干功率合成所需的相位一致性,需要对普通磁控管引入注入锁频技术,以保障工作频率和相位差的稳定性.本文在阻抗匹配的条件下,结合磁控管稳定振荡的条件,从等效电路的角度出发对磁控管注入锁频原理进行分析,给出了在小注入比和大注入比情况下磁控管的注入锁频理论,大注入比情况比小注入比情况给出了更大的锁频带宽.采用MATLAB对理论方程进行解析求解,同时通过三维粒子仿真软件对锁频理论进行了对比验证,得出了在不同注入比下磁控管的锁频带宽和相位差微分方程,给出了在不同初始相位下的相位差变化曲线,得到了A6磁控管在自由振荡和注入锁频工作下三维模拟仿真的输出功率、频率和波形.模拟结果表明,在两种情形预测的锁频带宽内,磁控管均能被锁定并稳定工作,在大注入比下大注入比情况比小注入比情况更为准确.

Coherent power-combining by using several magnetrons is essential because the output power of one single magnetron cannot meet the need of large-scale industrial applications. In order to obtain phase coherence condition of the power-combining of normal magnetrons, injection-locking technology should be adopted to make sure the stability of the operating frequency and phase differ- ence. Under impedance matching conditions, equivalent circuit of injection-locked magnetron is analyzed with the conditions of the magnetron stable frequency. The small injection-ratio and large injection-ratio situations of the injection-locked magnetrons are both derived. Furthermore, large injection-ratio situation indicates a greater frequency-locked bandwidth than small injection-ratio situation. Theoretical results are analyzed by MATLAB and injection-locked theory is verified by three-dimensional particle-in-cell simulation. The frequency-locked bandwidth and phase differential equation are given and curves of the phase difference are drawn for different initial phases. Output power and frequency of A6 magnetron are obtained by simulation under both free and injection-locked oscillation conditions. Simulation results show that magnetron can be locked and working stably in frequency-locked bandwidth predicted by both situations. Moreover, in the large injection ratio status the large injection-ratio situation is more accurate than the small injection-ratio situation.