YAN Sheng-mei,SU Wei,ZHANG Guo-liang.Design and fabrication of a sub-millimeter multi-beam folded waveguide structure[J].Optoelectronics Letters,2017,13(1):33-37 Design and fabrication of a sub-millimeter multi-beam folded waveguide structure Author Name Affiliation YAN Sheng-mei  Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China  SU Wei  Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China  ZHANG Guo-liang  Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China  Abstract:       A novel multi-beam folded waveguide (MBFW) circuit, which can enhance the output power and interaction efficiency of sub-terahertz (THz) traveling wave tube (TWT), is presented in the paper. Operating with fundamental mode and multiple electron beams means that a larger beam current can be used for a higher output power. The characteristics of the MBFW structure are analyzed and optimized. Compared with the single-beam folded waveguide (SBFW) TWT, the output power of the MBFW TWT increases from 3.64 W to 25.45 W at 140 GHz and its electronic efficiency increases from 1.06% to 7.4% under the conditions of an input peak power of 10 mW, a beam voltage of 9.55 kV and a current of 12 mA. The optimized MBFW structure can be successfully fabricated by micro milling, with dimension errors below expectation, and the measured transmission characteristics are in good agreement with the design. Hits: 3879 Download times: 0 View Full Text    Download reader