双极性流对低阻抗器件的影响

 分析讨论了双极性流对平面二极管发射电流的影响，并利用PIC程序对平面二极管中的双极性流问题进行了数值对比。在此基础上模拟研究了具有径向发射特点的低阻抗高功率微波器件MILO中的双极性流问题。结果表明：双极性流的出现使器件偏离最佳工作点，使输出功率和效率降低，电压越高，器件偏离最佳工作点就会越远，当电压高到一定值以后会使器件的工作点移至B-H曲线以下，器件处于过绝缘状态，不能正常工作。

Effects of bipolar flow on performance of microwave tube with low impedance

The effects of bipolar flow on the performance of planar diode are analyzed and simulated by a PIC code.The effects of bipolar flow in an MILO device with radial emission are simulated.Some qualitative conclusions in this kind of microwave tube with low impedance are presented.The beam current increase caused by the bipolar flow in the tube may remove the operation point away from the optimal operation point.As a result the microwave output power and efficiency of the tube decrease.When the voltage gets higher,the work point of the tube is further away from the optimal operation point.The operation point of the tube would move below of B-H curve when the voltage is high enough.The tube is over-insulated and can not work well.