Radioelectronics and Communications Systems

Research on ways to create THz pulse generators based on silicon IMPATT diodes

Andrii Bychok — 2024-03-25

The paper is devoted to considering issues related to the search for ways to create pulse power sources of the terahertz range. It presents the results of mathematical simulation of the energy and impedance characteristics of silicon impact ionization avalanche transit-time (IMPATT) diodes in the frequency range of 200–300 GHz and the elements of matching the impedance of semiconductor structure with the impedance of waveguide transmission line. Based on the calculation results, the diode structures were optimized to attain the maximum microwave power in the pulse mode. Parameters of experimental samples of silicon double-drift IMPATT diodes fabricated with due regard for the data of mathematical simulation are presented. The pulse microwave power of 0.416 W at 233 GHz with a microwave pulse duration of 35 ns has been obtained.

Development of compact Cherenkov devices with sheet electron beams in sub-THz and THz frequency ranges (review)

Sergiy Vlasenko — 2024-03-25

Results of both theoretical and experimental studies of the beam-wave interaction in compact vacuum electron devices of the clinotron type are presented and discussed. Several modifications to the interaction circuit and radiation output were proposed to improve the performance of clinotron tubes in the sub-THz and THz ranges. These modifications include optimization of the conventional clinotron design to enhance beam-wave interaction and ensure single-mode output radiation in an oversized cavity. Additionally, a new design approach was considered for the THz Cherenkov oscillators and amplifiers, which are based on the excitation of hybrid bulk-surface modes in circuits containing bi-periodic gratings. Theoretical studies were conducted using both “cold” and “hot” simulations with in-house and commercial software. The typical performance of experimental tubes operating in the frequency range of 90 GHz to 410 GHz is presented and compared with the theoretical predictions. Plans for future studies and the developments of THz tubes are also outlined.

Generation of electromagnetic waves based on interaction effects between moving charged particles and fields excited by them eigenmodes of waveguide and resonator structures (review)

Yuriy Prokopenko — 2024-03-25

The paper presents an overview of the authors’ scientific works, which are further developments in the scientific directions of SHF and EHF electronics, which were first developed by scientists, particularly Professor V. P. Taranenko. The possibility of propagation of weakly decaying electromagnetic waves in super dimensional electrodynamic solid-state structures, including those containing plasma-like medium, is demonstrated. Attention is paid to excitation mechanisms of eigenwaves and eigenoscillations of such structures, which are based on the Vavilov–Cherenkov effect, anomalous Doppler effect, or transient radiation. The generation of electromagnetic radiation in the interaction between the charged particle flows, and the fields of eigenwaves or eigenoscillations of such structures have been demonstrated. The possibility of mastering the millimeter and submillimeter wavelength ranges using multimode electrodynamic structures with dimensions acceptable for production is shown. Electrodynamic systems based on supercritical currents of the relativistic electron beam, such as virtod and virtod-BWT, are presented, in which the control of the amplitude-frequency characteristics of microwave radiation is implemented.

Study of near-threshold power discharge in miniature low-pressure microwave induction plasmatron

Anatoly Kuzmichev — 2024-03-25

The results of research using 2D simulation in the drift-diffusion approximation of a plasma discharge in a cylindrical dielectric cuvette of 14 mm diameter for a low-pressure induction plasmatron with pumping at a frequency of 2.45 GHz with near-threshold power of 10–25 mW are presented. Spatial distributions of discharge plasma parameters and absorption of electromagnetic energy are calculated. The magnetic field penetrates the plasma to the axis of the cuvette and has a solenoidal behavior with no strong skin effect. The results can be used to develop plasma generators for miniature radio-electronic and gas analytical devices.