Design, development and characterization of wide incidence angle and polarization insensitive metasurface absorber based on resistive-ink for X and Ku band RCS reduction

Abstract

This article deals with the design, development and characterization of a broadband, wide incidence angle and polarization-insensitive metasurface, which consists of periodic resistive-ink pattern printed on top of FR-4 dielectric substrate as a RADAR absorber. Geometrical dimensions of the proposed unit cell have been optimized numerically using CST-Microwave Studio to achieve 99% absorptivity for X and Ku frequency spectrum (8–18 GHz) under the normal angle of incidence and to achieve almost 90% absorptivity under the oblique angle of incidence up to 50° within X-Band to Ku-Band spectrum. Furthermore, it is reported that by having fourfold rotation symmetry, the designed structure is insensitive to the polarization of the incident wave. An equivalent circuit analytical modeling has also been performed to understand and verify numerical findings that are nearly in agreement. The designed absorber is fabricated and characterized using ABmm VNA and free space measurement method, for both normal and oblique angle of incidence, and it is found that measured characteristics are in agreement with numerical-analytical findings. Furthermore, the monostatic and bistatic Radar Cross Section reduction capability of the designed absorbing structure for both planar and curved surface (cylinder) is studied extensively to assess its potential application in X-Band to Ku-Band Spectrum.