We have demonstrated and developed a W-band 30 W continuous-wave folded waveguide traveling wave tube (CW FWTWT) with 13.5-kV operation voltage and 4.8 dB gain flatness. In this paper, we quantitatively study the relationship between operating voltage and the key geometric dimensions of a folded waveguide, which is the key to the design of the low-voltage TWT. In addition, problems of improving beam transmission and suppressing oscillations are also studied, and the related design methodologies of the long-range electron gun, periodic permanent magnet (PPM) focusing system, low-voltage standing wave ratio (VSWR) coupling system, and horseshoe attenuator are discussed. On the basis of the above analysis, we have designed and fabricated two types of W-band CW TWTs. The test results show that beam transmissions are over 98.5% at DC and better than 96.5% at the highest peak RF power. Measured saturated output powers are greater than 33.6 W with saturated gain more than 42.2 dB within frequency range of 91–99 GHz, and an improved gain flatness of 4.8 dB is achieved.

我们已经证明并开发了工作在13.5 kV工作电压和4.8 dB增益平坦度的W波段30 W连续波折叠波导行波管（CW FWTWT）。在本文中，我们定量研究了工作电压与折叠波导关键几何尺寸之间的关系，这是低压TWT设计的关键。此外，还研究了改善电子束传输和抑制振荡的问题，以及远程电子枪，周期性永磁体（PPM）聚焦系统，低压驻波比（VSWR）耦合系统和相关设计方法的相关设计方法。讨论了马蹄衰减器。在以上分析的基础上，我们设计和制造了两种类型的W波段CW TWT。测试结果表明，直流下的光束透射率超过98.5％，优于96。最高峰值RF功率为5％。在91–99 GHz频率范围内，测得的饱和输出功率大于33.6 W，饱和增益大于42.2 dB，并且增益平坦度提高了4.8 dB。