介绍了一种D 波段连续波行波管放大器。该行波管采用了高压缩比皮尔斯会聚电子枪、折叠波导慢波结构(FWSWS)、蓝宝石输能盒形窗、周期永磁聚焦系统、集中衰减器以及一级降压收集极，经过装配、焊接、排气、磁场调试等过程，得到了D 波段连续波放大器样管，并进行了流通率的调试和信号放大的测试。实验测试结果为：电子电压15.4 kV，电子流通率97%时，连续波输出功率7.3 W，中心频率140.2 GHz，增益24.6 dB，3 dB 带宽3 GHz。该放大器连续运行稳定，满足工程化要求。

A D band Continuous-Wave(CW) Folded Waveguide Traveling Wave Tube(FWTWT) is introduced. The high compress ratio Pierce electronic gun, Folded Waveguide Slow Wave Structure(FWSWS), sapphire transmission energy window, Periods Permanent Magnetic(PPM) focus system, concentrated attenuator, single-stage depressed collector are adopted in the FWTWT. After the processes of the assemblage, welding, exhaust and magnet installation, a D band CW FWTWT is obtained. In the experiment of electron transmission ratio and signal amplification, under the electron voltage of 15.4 kV and electron transmission ration of 97%, the maximum saturated CW output power, the output central frequency, the maximum gain and 3 dB bandwidth are 7.3 W, 140.2 GHz, 24.6 dB and 3 GHz, respectively. The tube works stably and satisfies the engineering requirement in D band.