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We present the results of the studies aimed at developing small-size traveling-wave tubes (TWTs) with multiple sheet electron beams, which operate in the short-wavelength part of the millimeterwaverange. Two versions of such TWTs are considered. The TWT operating at frequencies near 0.22 THz with a triple sheet beam, which interacts with the higher transverse mode of the slow wave structure in the form of a dual comb, is studied. We describe the design of the electronoptical system which forms a beam consisting of several sheets with elliptical cross sections having an area compression of about 16 units. We also consider a TWT with a slow-wave structure in the form of a 3D meander line with several channels for electron beams, whichis placed in a rectangular waveguide. On each side, this structure is supported by dielectric supports. A slow-wave V-band (50–70 GHz) structure has been designed for a TWT with channels for four sheet electron beams. The results of calculating electrodynamic characteristics of the slow-wave structure are presented along with the results of three-dimensional simulation of the processes of the electron–wave interaction by the particle-in-cell method. [ABSTRACT FROM AUTHOR]

This article presents the results of a design study of an electron-optic system (EOS) for a sheet-beam G-band traveling-wave tube. An electron gun providing a 0.1-A, 20-kV sheet beam emitted by a 0.8 mm × 0.8 mm curved cylindrical cathode is designed. The beam dimensions at waist position are 0.05 mm × 0.8 mm with a compression ratio of 16 in the vertical direction. A magnetic system providing 1.1 T magnetic field, which is nearly seven times higher than the Brillouin field, is designed, and beam transmission in the 0.1 mm × 0.85 mm beam tunnel is studied by 3-D particle-in-cell (PIC) simulation. It is demonstrated that the beam has a complex structure of particle distribution, i.e., a high-density central part (core) and a peripheral low-density part (halo). The effect of assembly tolerance on beam transmission is studied. The prototype gun is fabricated, which compresses the beam to 0.1 mm by electrostatic field only. The 135-mA current with 95% transmission through the 0.2-mm anode aperture is measured. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

For advanced telecommunications and radar systems, high-power miniaturized millimeter-band traveling-wave tubes (TWTs) are required. In this letter, we propose a meander-line slow-wave structure (SWS) that is suitable for multiple sheet beam interaction that helps achieve high power. The simulation of cold electromagnetic parameters of the V-band SWS demonstrates good transmission characteristics, wide bandwidth, and high interaction impedance. Hot performance of the V-band TWT amplifier with the proposed SWS is also studied. The 3-D particle-in-cell (PIC) simulation predicts that the designed circuit yields a stable gain in the 50 – 70 GHz frequency range with a 25 – 30-dB small-signal gain. 250-W average output power is attained from a 1.5 – 2.0-W input driving signal at 68.1 GHz. [ABSTRACT FROM AUTHOR]

For a relativistic backward-wave oscillator (RBWO), various nonstationary phenomena, such as irregular transients, mode competition, self-modulation, and chaos, are typical. Phase locking by injection of the external signal helps to minimize transient times and to stabilize a single-frequency regime of operation. In this paper, phase locking of an RBWO with end reflections is considered. The results of time-domain numerical modeling are presented, which reveal an intricate pattern of the phase-locked operation. In particular, a possibility of rapid frequency switching by RF priming is demonstrated. [ABSTRACT FROM PUBLISHER]