Absorption and cancellation radar cross-section reduction metasurface design based on phase- and amplitude-control

Wider band and deeper radar cross section (RCS) reduction by lower profile is always a very noticeable subject in stealth material researches. Most of researchers have designed and measured the RCS reduction bandwidth with 10 dB standard, that is, the return energy is reduced by 90%. In this paper we present a dual-mechanism method to design a single-layer absorptive metasurface with wideband 20-dB RCS reduction by simultaneously combining the absorption mechanism and the phase cancellation mechanism. Firstly, the impedance condition for 20-dB RCS reduction is theoretically analyzed considering both the absorption and the phase cancellation based on the two unit cells, and the relationship between the surface impedance and the reflection phase/amplitude is revealed. According to these analyses, two unit cells with absorption performance and different reflection phases are designed and utilized to realize the absorptive metasurface. Then, we simulate the plane case and the cylinder case with the designed flexible metasurface and compare them with the counterparts with equal-sized metal. Finally, the sample is fabricated and characterized experimentally to verify the simulated results. Both numerical and experimental results show that the 7-mm-thick single-layer absorptive metasurface features a wideband 20-dB RCS within 6.10–12.15 GHz (66%). Our designed metasurface features wideband, 20-dB reduction, polarization insensitivity, light weight and flexible, promising great potential in real-world low-scattering stealth applications.