A Modified Double Staggered Grating Waveguide Slow Wave Structure for Sub-THz Traveling Wave Tubes

• Published in: IEEE transactions on electron devices Vol. 70; no. 6; pp. 1 - 7
• Main Authors: Zhao, Chen, Xu, Hang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Blades; Couplers; Cross-sections; Design optimization; Double staggered grating waveguide (DSGW); Electric fields; Electron beams; Gain; Gratings; Impedance; Maximum power; Millimeter waves; Power generation; slow wave structure (SWS); sub-THz; traveling wave tube (TWTs); Traveling wave tubes; Traveling waves; Waveguides
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3242218

A modified double staggered grating waveguide (DSGW) slow wave structure (SWS) is proposed for millimeter-wave and sub-THz traveling wave tubes (TWTs). Gratings with a cross section outline of exponential curves are applied instead of the traditional rectangular cross section. The proposed SWS owns a higher interaction impedance compared to DSGW, resulting in higher output power and gain. With proper design and optimization of the input-output couplers, the proposed SWS can have a wide <inline-formula> <tex-math notation="LaTeX">-</tex-math> </inline-formula>15 dB impedance bandwidth, extending from 192 to 230 GHz. Particle-in-cell (PIC) simulations are carried out for a TWT with sheet electron beam (SEB) and the main SWS having 70 periods. Such a TWT provides a maximum power of 116.64 W which indicates a significant improvement compared with the traditional DSGW.