Xuyuan Chen

H-Plane and E-Plane Loaded Rectangular Slow-Wave Structure for Terahertz TWT Amplifier

A novel miniaturized rectangular slow-wave structure (SWS), composed of both H-plane and E-plane corrugations, is proposed for submillimeter or terahertz vacuum electron traveling-wave tube (TWT) devices. The advantage of this SWS is to enhance the interaction impedance, therefore, resulting in higher gain and improved output power of the device. In addition, this structure geometry permits design flexibility to achieve a better dispersion behavior (linear dispersion and wider bandwidth) and easy fabrication by available microfabrication processes. Incorporating an H-plane and E-plane load in the SWS design, we achieved a higher performance TWT amplifier with the central frequency of 400 GHz. Both electromagnetic characteristics and beam-wave interaction analysis are investigated using the 3-D electromagnetic software Computer Simulation Technology studio. The simulation results show that an enhanced interaction of the SWS is obtained, and the amplifier has wide instantaneous bandwidth of 80 GHz and 19.5-dB small signal gain at 400 GHz for 17-kV beam voltage and 20-mA beam current. A saturated output power of more than 19 W is obtained from the large-signal simulations.

Improved Design and Microfabrication of

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-Plane Loaded Rectangular Slow-Wave Structure for THz TWT Amplifier

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Cold-test analysis of H-plane and E-plane loaded rectangular slow-wave structure

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H-plane loaded and phase velocity tapered SWS for improved performance of TWT THz sources

</tex-math></inline-formula> dB over a frequency range 360–450 GHz. To improve the beam-wave interaction and enhance the saturated output power of the TWT, the SWS with tapered design is implemented. By tuning the period, the wave is resynchronized with the beam at the end of the SWS, resulting in more than 60% increase in the saturated output power across the 80-GHz bandwidth. In addition, the sensitivity of the output power of the TWT to the fabrication tolerance of the individual geometrical parameters is also studied in detail. It is found that the output power reduces by 80% for approximately 2% variation in the synchronized beam voltage. The KMPR-based UV-LIGA technique is adopted to fabricate the <inline-formula> <tex-math notation=LaTeX>

COMSOL multiphysics modeling and simulation of traveling wave tube amplifiers

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METHOD FOR REDUCING SPECKLES AND A LIGHT SOURCE USED IN SAID METHOD

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