Peculiarities of microfabrication the slow-wave structure for millimeter-band backward-wave oscillator based on the pseudospark-sourced electron gun

Abstract

Design, development, and microfabrication of vacuum electron components and devices suitable to operate at millimeter- and terahertz-band frequencies attracted great attention for potential applications in scientific and industrial fields. The power of vacuum electron devices mostly depends on the electron beam current density. Pseudospark-based electron guns are considered as one of the possible and promising sources of high-current electron beams (including sheet electron beams). The concept of pseudospark discharge was proposed by Christiansen and Schultheiss at the University of Erlangen, Germany, in 1977, and primarily used as an electron beam source in their following research. Advantages of the pseudospark discharge based hollow cathode electron guns include high achievable electron beam current and the absence of a focusing magnetic field owing to the ion focusing mechanism.
In this work, we consider the peculiarities of microfabrication of the slow-wave structure for the V-band backward-wave oscillator (BWO) with a pseudospark discharge based electron gun. The BWO is driven with a 10-20 A sheet electron beam accelerated to 30-40 kV with a pulse duration of 50-100 ns. The sine-waveguide slow-wave structure (SWS) was designed and simulated using the COMSOL Multiphysics package and CST Microwave Studio. CNC milling machine was utilized for the microfabrication of the SWS. An original approach to microfabricate sine-waveguide SWS was developed which allowed for the fabrication of small-sized features of the device using a conventional CNC milling machine and commonly available milling tools. For this, the SWS structure was constructed as two asymmetric parts with side surfaces of the SWS structure to form the whole device upon assembly. Dimensions of the fabricated SWS were controlled by scanning electron and optical microscopy against theoretical values.
This work was supported by the cooperative grant of the Russian Foundation for Basic Research # 19-58-45040 and DST # INT/RUS/RFBR/381

Speaker

Anton Pavlov
Saratov State University
Russia

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