Plasma antenna systems consisting of discharge elements have great practical application prospects due to their ability to quickly adjust parameters over a wide range. In this work, the radiation patterns of a 30 mm long linear antenna surrounded by 16 standard T8 fluorescent lamps were measured by using a spectrum analyzer with a tracking generator. The radiation pattern of the system is measured by connecting the output of the spectrum analyzer tracking generator to a linear antenna and connecting the input of the spectrum analyzer to the receiving broadband horn antenna. The work features experimental measurements over a wide frequency range of 0.5 to 1.5 GHz and a wide discharge with current values from 35 to 200 mA. The specific frequency band and uniquely selected geometry allowed for the investigation of both the in-phase and out-of-phase antenna modes, while some modes were found to have a narrow directional radiation pattern, within 50 degrees, with a beam width of −3 dB. The parameters of the gas-discharge plasma were also evaluated using drift theory, as well as using the microwave transmission of the 20 GHz signal. The electron density value corresponding to the used discharge currents was approximately from 4 × 10¹¹ to 7 × 10¹⁰ cm⁻³.

This study presents a detailed analysis and refinement of a novel plasma electron spectroscopy technique. The proposed method is designed for integration with gas chromatography systems to facilitate chemical composition analysis of substances. Unlike classical collisionless electron spectroscopy, plasma electron spectroscopy functions without the need for high vacuum conditions and remains effective even when electrons undergo multiple elastic collisions. The core principle of this technique involves the detection of Penning electrons within an ionized gas mixture, composed of a base gas and analytical impurities. This detection necessitates the application of established plasma diagnostic techniques, such as probe measurements. A key outcome of this approach is its applicability at elevated pressures, extending up to several hundred Torr. The method’s efficacy has been validated across an extensive range of chemical compounds, from simple inert gases to complex, multicomponent organic mixtures. Furthermore, the feasibility of analyzing both gaseous mixtures and solid samples is demonstrated. Although detailed examination revealed that the resulting curves do not always correspond to conventional electron spectra, the obtained dependences provide a reliable means of detecting Penning electrons. Analysis of these electrons enables the detection and characterization of the studied impurities. Overall, this method offers significant potential for high-pressure impurity detection and identification in gaseous systems.

Electrical characteristics of atmospheric-pressure glow discharge at constant currents up to 40 mA in flows of atomic and molecular gases have been measured at volume flow rates varied within...

A system for microwave diagnostics of low-temperature non-stationary atmospheric plasma jets is proposed, the principle of operation of which is based on the registration of changing in the quality factor of the main mode of the electric type of a cylindrical microwave cavity resonator. The time dependences of the average volumetric conductivity of a plasma jet of a barrier discharge in a helium flow are measured. The discharge was powered from an alternating voltage source with a frequency of 9 kHz. Such a low frequency of the supply voltage made it possible to distinguish individual pulses of breakdowns of the barrier discharge.

This article solves the problem of determining the influence of an extended plasma jet on the radiation pattern of a short-grounded antenna in the frequency range of 1-3 GHz. The electron density and the electron collision frequency are set such that they correspond to atmospheric plasma jets of a barrier discharge in a helium flow. The problem of determining the radiation pattern is solved numerically using ANSYS HFSS and analytically using simple theoretical expressions for the field of a short antenna. The results using these two approaches are consistent with each other well. Based on the obtained results, a novel microwave diagnostic method for the atmospheric plasma jets was proposed.

Electrical characteristics of a glow discharge of atmospheric pressure with a constant current of up to 40 mA in atomic and molecular gas flows with a volume flow from 0.5 to 5 l/min were measured. It was found that in the flow of molecular gases the voltage drop on the discharge significantly depends not only on the rate of gas blowing, but also on the polarity of the supply voltage. With increasing of the blowing rate the discharge in oxygen and nitrogen becomes unstable, and the voltage on the discharge gap increases by several hundred volts. With a positive polarity of the supply voltage both effects are much more pronounced than with a negative one. In helium and argon flows with given blowing rates the polarity of the voltage on the electrodes does not affect on the discharge mode.