回旋行波管分布式介质加载高频结构研究

Study on Distributed-Loss Loaded Interaction Structure for Gyro-TWT

利用线性理论对Ka波段工作模式为TE01模的回旋行波管进行了稳定性分析,计算了介质加载条件下工作和寄生模式的传播损耗,以及不同传播损耗下工作模式的起振电流;对不同介质加载条件和工作电流,给出了3个主要寄生模式的起振长度;确定了介质加载厚度以及相对介电常数等参数。计算结果表明,在优化得到的介质加载条件下,寄生模式在其各自振荡频点的单位长度传播损耗大于抑制各寄生模式返波振荡所需最低损耗值要求;工作模式起振电流大于设计所需工作电流;寄生模式的起振长度大于设计的介质加载段和未加载段长度;设计的介质加载参数能够满足抑制工作和寄生模式自激振荡的要求。利用优化设计的高频结构及介质加载参数,进行了整管热测实验,得到了输出功率160kW,饱和增益40dB,效率22.8%以及3dB带宽5%的回旋行波管。

The linear theory is used to analyze the stability of a Ka-band TE01 mode gyro-TWT.Propagation loss of operation and parasitic modes,the start currents of operation mode under different propagation loss are calculated.Start lengths of the three main parasitic modes under different loss-loading conditions and operation currents are given.Dielectric loss parameters including thickness of loss layer and relative permittivity are determined.Under the optimized dielectric loaded condition,propagation loss in unit length of parasitic modes exceeds the minimum of loss value to suppress oscillation,the start current of operation mode exceeds beam current,the start lengths of parasitic modes are longer than those loaded and unloaded section,the dielectric loading scheme is capable of suppressing oscillation of both operation and parasitic modes.Taking advantage of the optimized parameters of loaded dielectric,a high gain scheme has been demonstrated in a 34GHz,TE01 mode gyro-TWT,producing 160 kW saturated output power at 40 dB stable gain and 22.8% efficiency with a 3-dB bandwidth of 5%.