Slow-wave structure (SWS) is a core part of a traveling-wave-tube (TWT) amplifier. In this letter, the planar microstrip meander SWS on a dielectric substrate at V-band (50-70 GHz) is studied. The basic electromagnetic parameters of the SWS are calculated. The SWS circuits are designed and fabricated, and good transmission characteristics are measured. The SWS developed is characterized by a wide bandwidth and a relatively-large slow-wave factor, and is suitable for a low-voltage TWT with the sheet electron beam.

We report the results of the design, simulation, fabrication, and cold-test measurements of millimeter-band 2D planar microstrip slow-wave structures (SWSs) on dielectric substrates. Such structures have a high slow-wave factor, which allows for low-voltage operation and reduction in the size and weight of the device. A low-cost and flexible fabrication technology based on magnetron sputtering and subsequent laser ablation has been developed and is reported in the paper. Microstrip meander-line SWS circuits at V-, W-, and D-bands have been fabricated and characterized. The fabrication of ring-bar planar SWSs by the photolithographic method is also discussed. Experimental measurement of S-parameters of the fabricated structures reveals good transmission properties. Return loss (S11) does not exceed −10 dB and attenuation is about 2 dB/cm in the V-band, 10 dB/cm in the W-band, and 8.5 dB/cm in the D-band.

A miniature planar meander-type slow-wave structure (SWS) for a W-band traveling-wave tube is studied. Computer simulation of the SWS electrodynamic parameters is performed. A new technology for fabrication of planar microstrip SWSs with the aid of laser ablation is proposed. The S-parameters of the SWS are experimentally studied. The experimental data are in good agreement with the results of the 3D computer simulation. Output characteristics of the traveling-wave tube with a sheet electron beam and planar SWS are calculated.

In this article, the design approach for a V-band miniaturized oscillator with a pseudospark-based high-current-density sheet electron beam source is presented. The hollow cathode electron gun has been designed and developed. In the experiment, the ~10-A current in the hollow-cathode phase has been measured. The high-frequency structure comprised of a truncated sine waveguide slow wave structure (TSW SWS) with wideband-matched output couplers has been designed, optimized, and simulated. The simulations show good transmission characteristics of the structure. The operation of a backward-wave oscillator with the designed TSW SWS driven by a 10-A, 40-kV sheet electron beam has been investigated by using 3-D particle-in-cell simulations. The maximal output power of 70 kW has been attained in the simulation. Frequency tuning within the 10-GHz frequency band has been demonstrated.

Nowadays, there is a strong interest in miniature and high-power vacuum electron devices (VEDs) operating in millimeter and sub-THz bands. VED sources of coherent sub-THz radiation are required for many applications, especially for future advanced high-data-rate telecommunication systems. In this work, we present the results of design study of a meander-line slow-wave structure (SWS) suitable for multiple-sheet-beam operation to achieve a high level of output power. The results of cold-test electromagnetic simulation show a possibility of operation at beam voltage of 12 kV with high values of interaction impedance up to $12 \Omega $ . The 3-D particle-in-cell simulation of performance of the traveling-wave tube with 400-mA, 12-kV multiple sheet electron beam predicts up to 26-dB gain and up to 376-W output power.