140GHz多注折叠波导结构的特性与微铣削工艺研究

Characteristics of Novel Multi-Beam 140 GHz Folded-Waveguide Structure Fabricated by Micro-Milling

多个电子注是提升THz辐射源输出功率的一种有效办法,折叠波导是一类广泛应用于THz行波管的慢波结构,为此本文对一种三注折叠波导结构进行了研究。首先,完成了该结构冷测特性与注波互作用特性的理论分析,获得了一组优化的结构参数;其次,由于折叠波导结构具有准二维的特点,突破微铣削工艺相关关键技术,完成了该结构的制作;最后,搭建实验测试平台完成了该结构传输特性的测试,并与设计结果进行比较。模拟结果表明:中心频率点在140GHz、注电压与电流分别为9.55kV与12mA、输入功率为10mW时,同单注结构相比,输出功率从1.82提升到了12.73W;电子效率从1.59%高到了3.7%;传输特性的实验值同设计值保持了很好的一致性。该方法为THz行波管输出功率和电子效率的提高提供了新的参考。

The characteristics of multiple-beam folded waveguide（ MBFW） structure were theoretically analyzed to optimize its design and enhance the output power of terahertz traveling wave tubes（ TWT）. The design of D-band Three-Beam Folded Waveguide Structure was optimized by theoretically analyzing the dispersion and wavebeam interaction. Next,the optimized MBFW structure was successfully fabricated by micro milling,with dimension errors below expectation. Finally,the transmission properties of the newly-developed MBFW circuit was tested with the home-made experimental platform. The test results show that the novel MBFW significantly improved the output power and electronic efficientcy of THz TWT. Compared with SBFW TWT,the output power of MBFW TWT increased from 1. 82 to 12. 73 W at 140 GHz and its electronic efficiency increased from 1. 59% to 3. 7% under the conditions： an input peak power of 10 m W,beam voltage of 9. 55 k V and curent of 12 m A. The mesured and predicted results of MBFW circuit were in good agreement.