ANISOTROPIC IMPEDANCE CYLINDRICAL METASURFACE FOR SELFADAPTIVE CANCELLATION OF SCATTERING WAVES WITH ANY POLARIZATION

Abstract

The article is devoted to the topical problem - reducing the radar cross-section (RCS) of cylindrical objects using anisotropic metasurfaces (MS). The purpose of the work is to study anisotropic impedance MSs for self-adaptive (to the irradiation frequency) RCS suppression of cylindrical metal surfaces when irradiated by linear (LP) and circular (CP) polarized waves. To achieve this goal, the known principles of operation, design and capabilities of MSs for reducing the RCS of both flat and cylindrical metal surfaces, including surfaces of electrically small radius, were analyzed. The 2D problem of scattering a plane electromagnetic wave on the model of a cylindrical metasurface (CMS) in the form of a circular cylinder with anisotropic homogenized impedance boundary conditions of a general form is considered. Using the eigenfunction method, analytical expressions are obtained for the scattering matrices of a cylindrical metasurface in linear and circular polarization bases. Scattering matrices make it possible to solve various problems of synthesizing the impedance tensor of the CMS on given scattering characteristics in the LP and CP bases. In particular, a diagonal impedance tensor of the CMS has been synthesized, which provides that the fields of scattering of TE-, TM-polarized waves as well as two circular co-polarized waves are antiphase. The problem of synthesizing the impedance tensor of the CMS from a given zero trace of a diagonal scattering matrix with self-adaptive (to the irradiation frequency) cancellation of waves with any polarization in the low-frequency region has been solved. It is shown that the radar cross-section reduction of the CMS in the reverse direction is from 60 to 10 dB in an ultrawide range of ka values from 0.02 to 0.4. The scattering characteristics of two models of camouflage coatings are calculated. It is shown that the reactance CMS based on meta-particles in the form of rectangular strips reduces the RCS by 10 dB in the low-frequency band of 200– 520 MHz with the incidence of the TM polarized wave and by 5 dB in the band of 480–720 MHz in the case of incident TE polarized wave.