Wideband, polarization independent electromagnetic wave absorber using cross arrow resonator and lumped SMD resistors for C and X band applications

Abstract

In this work, a polarization independent and wideband electromagnetic (EM) waves absorbing frequency selective surface (FSS) structure is presented. The unit cell of the proposed FSS consists of an assembly of cross arrow resonators with four SMD resistors mounted on it, to enhance the absorbance bandwidth. This unit cell also possesses a four‐fold symmetry which makes it polarization insensitive. The designed unit cell is compact with the length and width dimensions as 0.19λL × 0.19λL, and thickness of 0.13λL, where λL is the guided wavelength corresponding to the lowest operating frequency. The proposed absorber is theoretically and experimentally tested for its absorbance, cross‐polarization level, and radar cross section (RCS) characteristics. The computer‐aided simulation and practical measurements indicate that the proposed absorber offers more than 90% (with a fractional bandwidth of 93%) absorbance for normal incidence at 4.5–12.4 GHz frequency band. The cross‐polarization reflection coefficient analysis indicates that the proposed FSS configuration behaves as an absorber and not a polarization convertor. The input impedance plot, surface current distribution, and E‐field distribution of the unit cell were also analyzed and presented to understand the absorbance mechanism. The RCS of the proposed FSS is compared with the RCS of a reflective (metallic) sheet to analyze its suitability for practical applications (RCS reduction) within the working band. The 3D simulated and 2D calculated RCS results indicate that the proposed FSS is suitable for wideband EM wave absorber applications.

Novel Local-Chiral Metamaterial: Effective Modulation of Amplitude & Phase for Wideband Polarization-Insensitive Absorption

“…Currently, there are various design tools or methods available to achieve wideband absorption performance in different EM wave bands, such as transformation optics, , using chaos, , complementary metamaterial structures, , space-filling techniques, and resonator material tailoring. − Especially for the GHz band, wideband absorption design is of great significance in improving the performance of electronic equipment and developing military stealth technology. In general, there are three available methods for designing wideband absorption in microwave band based on structural design: horizontal arrangement, − vertical arrangement, ,− and loading lumped elements. − By utilizing the principle of mutual superimposition of different resonant frequencies, the absorption bandwidth can effectively be broadened by multiple resonant points generated from the horizontally tiling or vertically stacking of different MMA structure patterns. Among them, one novel design method for the broadband absorbers design is the selective absorption of EM waves with different polarization modes which can be achieved by constructing chirality in metamaterial units, , and this design method has gradually been applied to the design of broadband absorbers in recent years. , However, the high Q-factor of the low-resistance metallic materials utilized in the resonant unit of these designs makes it difficult to further widen the absorption bandwidth.…”

“…Among them, one novel design method for the broadband absorbers design is the selective absorption of EM waves with different polarization modes which can be achieved by constructing chirality in metamaterial units, , and this design method has gradually been applied to the design of broadband absorbers in recent years. , However, the high Q-factor of the low-resistance metallic materials utilized in the resonant unit of these designs makes it difficult to further widen the absorption bandwidth. Therefore, researchers have proposed two alternative methods: replacing resonant units with lossy resistive films or loading lumped resistors ,− at appropriate positions in resonant units.…”

Design and Analysis of a Broadband Microwave Metamaterial Absorber

“…Thi Kim Thu Nguyen designed a simple structure absorber, using a simple design of the fractal structure and loading lumped resistors to achieve the effect of covering both the X-band and the Ku-band [34]. Awanish Kumar designed a metamaterial absorber consisting of a crossed arrow resonator and four SMD resistors to achieve high absorption covering the C-band and X-band, with near-perfect absorption in some frequency bands [35].…”