【摘要】 首先描述出7腔23注相对论速调管模拟过程中出现的收集极电子回流现象,分析该现象产生的原因,利用CHIPIC软件从收集极结构、输出腔距离收集极长度、聚集磁场强度三个方面研究其参数与电子回流量的关系。通过多次模拟实验得到以下结论:收集极入口处及其内表面紧贴电子运动轨迹时,回流减小;输出腔距离收集极长度L>12 mm时,回流随L减小而减小,L=12 mm时,回流量达到最小值,L<12 mm后,回流又逐渐增加;从输出腔下游开始沿Z向逐步降低聚集磁场强度,回流现象减弱。最后根据以上分析选择适合的参数,对整管进行模拟,电子注电压为28 kV,总电流43 A,输入信号功率61 W,频率5.6 GHz,获得功率为346.5 kW,平均效率约28.8%,增益37.54 dB的稳定输出信号,且无反射电子回流。证明在保证输出信号增益与效率的前提下,该方法成功抑制了速调管收集极回流现象。更多还原

【Abstract】 Electrons returning phenomenon in simulation of a 7-cavity 23-beam relativistic klystron is described and the reason is analyzed.CHIPIC code is used to investigate the relationship between the electrons returning and some factors including the collector structure,the distance(L) between the output cavity and the collector,and the magnetic field intensity.Some conclusions are obtained through the simulations:when the inlet and the inner surface of the collector are close to the electron trajectory,the electrons returning tends to decrease;the electrons returning decreases with the decreases of the distance between the output cavity and the collector and reaches the minimum value at L=12 mm,and then it will increase gradually;along with downstream of output cavity,reduction of magnetic field intensity can decrease electrons returning.Finally,according to the above analysis,suitable parameters are chosen to simulate the whole tube.The electron beam voltage is 28 kV,the total current is 43 A,the power of input signal is 61 W,the frequency is 5.6 GHz,the output power is 346.5 kW,the average efficiency is about28.8%and the gain is 37.54 dB.The output signal is stable and there is no electrons returning.It is proved that this method is effective to restrain the electrons returning from the collector in klystrons on the premise of ensuring the output signal gain and efficiency.更多还原