Background Dielectric Barrier Discharge (DBD), as a typical non-equilibrium plasma generation technology, has demonstrated unique physical properties and broad application potential in the field of electromagnetic wave dynamic regulation due to its advantages such as stable operation and easy regulation of plasma parameters.

Purpose This study innovatively proposes a dielectric barrier discharge-stepped rectangular waveguide coupled structure, aiming to systematically investigate the attenuation mechanisms and regulation laws of DBD plasma on low-power high-frequency time-varying electromagnetic waves.

Methods Based on the multi-physics plasma fluid model as the theoretical basis, by varying factors such as gas pressure, excitation source type, and AC excitation source frequency in the DBD process, the attenuation characteristics of dielectric barrier discharge plasma on low-power high-frequency time-varying electromagnetic waves were investigated.

Results The research results indicate that the attenuation effect of DBD plasma on electromagnetic waves exhibits significant dynamic evolution characteristics. In the initial stage of plasma generation, due to the extremely low electron density in the discharge space and the incomplete ionization collision reaction, electromagnetic waves penetrate the discharge region almost without loss. As the discharge process continues, the ionization collision reaction intensifies, the electron density in the discharge space rapidly increases, and the interaction strength between plasma and electromagnetic waves significantly enhances, leading to a rapid increase in the absorption and reflection efficiency of electromagnetic waves. Meanwhile, gas pressure influences the reaction rate of dielectric barrier discharge. Within a specific pressure range, increasing or decreasing the gas pressure can suppress or slow down the occurrence of plasma discharge, thereby regulating the transmitted electromagnetic waves. As the frequency of the AC excitation source increases, it leads to a higher number of discharges, a shorter electric field cycle, and an enhanced instantaneous intensity of the electric field. This accelerates the ionization and multiplication processes of electrons, drives a rapid rise in electron density, and ultimately optimizes the attenuation effect of the plasma on the transmitted electromagnetic waves. Furthermore, the absorption and reflection power curves of the plasma to the low power electromagnetic waves have an obvious trend of fluctuation with the progress of the dielectric barrier discharge reaction, but the overall attenuation effect of the electromagnetic waves is gradually enhanced.

Conclusions These research results can provide theoretical guidance and application value for the design of high-performance electromagnetic shielding materials and the development of microwave limiter.