Active Control of Electromagnetic Attenuation Characteristics of Planar Inductively Coupled Plasma

In this article, an inductively coupled plasma (ICP) source with planar transparent cavity is designed, and the active control of ICP on the attenuation effect of electromagnetic wave is studied. The scattering parameters calculation model of ICP is established based on the COMSOL fluid model combined with Z transform finite-difference time domain (ZT-FDTD) method. A point wave source composed of continuous reflection waves in the plasma is observed through the numerical simulation of the model, and the location of the wave source depends on the spatial distribution of the peak electron density. The effects of different pressure (10 mtorr–1 torr), working gas (Ar and O₂), and power (200–600 W) on the electromagnetic scattering characteristics are compared through numerical calculation and experimental measurement. The results show that the attenuation frequency band and amplitude can be actively controlled by changing external factors of ICP, such as gas pressure, working medium gas, and power. With the increase of power, the attenuation peak moves to the high-frequency band. With the increase of pressure, the fluctuation of attenuation curve is enhanced, and the attenuation bandwidth is increased. The O₂-ICP is more capable of absorbing wave power of the low band below 6 GHz, while the Ar-ICP is more effective in 6–14 GHz. The research results broaden the active stealth mode of aircraft in complex electromagnetic environment.