Multi-octave radar cross section reduction via integrated dispersion engineering of polarization-conversion metasurface and metamaterial absorber

In this paper, we propose a method of achieving multi-octave radar cross section (RCS) reduction by simultaneously engineering the dispersion of polarization-conversion metasurface (PCM) and metamaterial absorber (MA). To this end, a three-layer sandwich structure is devised, with two PCMs as the lower and upper panels and one MA as the lattice core structure. By engineering dispersions of the two PCMs, high-efficiency cross-polarization reflection can be achieved in two separate bands with a wide gap in between them. To bridge this gap, the absorption band of the MA is tailored by engineering the dispersion of spoof surface plasmon polariton (SSPP) modes excited on the MA. In this way, the three operating bands of the two PCMs and the MA can meet end-to-end, spanning over a multi-octave band. To demonstrate this method, we design a MA operating in 7.2–16.8 GHz, two PCMs operating in 16.0–35.0 GHz and 2.0–8.0 GHz. The combined three-layer structure can reduce RCS by more than 10.0 dB in 2.0–35.0 GHz, with a bandwidth more than 1:17. Both the simulation and experiment results verify the design. This work provides an alternative method of designing ultra-wideband RCS reduction structures and the method can also be extended to designing multi-functional planar or conformal structures. (letter)