Research On Integrated Radiation-scattering Multifunctional Rf Aperture Based On Active FSS

With the rapid development of advanced stealth and detection technology,the problem of radar cross-section reduction has been paid more and more attention.Frequency Selective Surface（FSS）is used in radar RF aperture stealthy mask for its characteristic of frequency selective.Although the Radar radomes of band-pass FSS can ensure the normal transmission of the antenna array in the working band,the monostatic Radar Cross Section（RCS）outside the working band can be reduced.However,the core application scenario of RF aperture in the future is the modern battlefield environment full of complex and changeable electromagnetic waves,which is undoubtedly a full challenge for the radar stealth camouflage system.Thus,the Frequency Selective Absorber（FSA）based on lumped components have emerged.FSA can not only allow the required electromagnetic wave to be transmitted normally in the working band,but also absorb the electromagnetic wave outside the working band,resulting in a reduction effect on both monostatic and bistatic RCS.In this paper,a single-layer bandpass FSS based on multi-mode resonator working in 5G（sub-6G）band is proposed to reduce the interference and processing cost of communication system.By using metasurface element and multimode resonance theory to suppress the grating flap,the size of the element is only 0.08λ₀（λ₀ is the resonant wavelength of the passband center frequency）,and the proposed FSS can maintain stability at a large oblique incidence of 60°.The results of electromagnetic full wave simulation,circuit simulation and experimental test are in good agreement,which verifies the feasibility of the proposed FSS.Subsequently,a phased array with a novel wideband RCS reconfigurable is proposed,which integrates a Frequency Selective Reflector（AFSR）with an electrically reconfigurable band for low scattering applications.The designed AFSR can control the absorption intensity of the AFSR by changing the PIN diode voltage of the lossy layer,and control the notch band transmission window by changing the reverse voltage of the varactor diode of the lossless layer.The radiation pattern of the proposed 8×4 antenna array maintains a peak gain of 19.3 dBi.The radiation beam scanning Angle can reach±45°.The dynamic range of smooth change of RCS reduction at dual polarization absorption frequency is greater than 10 dB.The results of electromagnetic full-wave simulation,circuit simulation and experimental test are in good agreement,indicating that the new phased array has the functions of frequency agility,beam scanning and dynamic out-of-band RCS regulation.