提出了一种基于开槽介质基底的卷绕微带线慢波结构.由于金属曲折微带线印制在介质基底的半圆形槽中, 这种卷绕微带线慢波结构非常适合圆形电子注行波管, 从而使得采用这种新型慢波结构的行波管可以利用传统的周期永磁磁场进行聚焦.文章对提出的卷绕微带线慢波结构的色散特性, 耦合阻抗, 传输特性及注-波互作用进行了分析.和传统的平面微带线慢波结构相比, 提出的卷绕微带线慢波结构具有更低的相速、更弱的色散和更高的耦合阻抗, 从而使得其适合于低电压、宽频带、小型化的毫米波行波管.将同步电压及直流电流分别设置为6550 V及0.1 A的情况下, 基于该卷绕微带线慢波结构的Ka波段行波管在35 GHz处能够输出42.32 W的功率, 对应增益为26.26 dB, 且均匀聚焦磁场只需0.4 T.

A folded microstrip meander line (FMML) slow-wave structure (SWS) based on slotted dielectric substrate is proposed. Due to the metal meander line printed in a semi-circular slot of the dielectric substrate, the proposed FMML SWS is very suitable for traveling-wave tubes (TWT) with cylindrical electron beam (CEB), which can be focused by a traditional periodic permanent (PPM) magnetic focusing system. The analyses of dispersion characteristics, coupling impedances, transmission properties and particle-in-cell (PIC) of the proposed FMML SWS are investigated. Compared with traditional planar microstrip meander line (PMML) SWS, the FMML SWS has the advantages of lower phase velocities, weaker dispersion and higher coupling impedances, which make the FMML SWS suitable for developing low-voltage, wideband and miniature millimeter-wave TWTs. With a focus magnetic of only 0.4 T, a Ka band TWT with the FMML SWS is capable of delivering 42.32 W output power with a corresponding gain of 26.26 dB at 35 GHz, while the voltage and the current of the electron beam are set to be 6 550 V and 0.1 A, respectively.