Ultra-wide-band plasma composite absorbers enhanced by phase gradient metasurface incorporation

To overcome some drawbacks in the application of plasma stealth technology, a composite absorbing structure composed of a closed plasma and a phase gradient metasurface (PGM) for broadband abnormal reflection is proposed. According to the polarization conversion function of PGM and the anomalous regulation of reflected waves, a PGM for broadband reflective polarization conversion based on a biarc metallic structure is designed to realize linear polarization conversion. The cross-polarization conversion rate reaches more than 90% in a wide frequency range of 7.1–23.4 GHz, and an abnormal reflection angle of ∼44.5° can be generated at a frequency of 12.0 GHz. The plasma structure is superimposed with the designed PGM to construct a composite absorbing structure (PS-PGM), and the electromagnetic attenuation effect of x-polarized waves of different frequencies is studied. It is discovered that adjusting the discharge power increases the attenuation effect of the PS-PGM and by adjusting the pressure of the working gas, the effective attenuation frequency band of the PS-PGM can be changed. As a result, the wave-absorbing properties of the plasma are improved because the propagation distance of electromagnetic waves in the plasma structure can be increased due to the abnormal reflection of electromagnetic waves by the PGM.