Angle of Incidence and Polarization Insensitive Ultra-Thin Ultra Wide-Band Metamaterial Absorber based on Novel Non-Linearity in Unit Cell Design

Abstract

A new design of an ultra wide-band metamaterial absorber (MMA), with appreciable high absorptance insensitive to angle of incidence and polarization angle is presented in the manuscript. The MMA structure consists of three concentric rings with non-linear variation in the spacing and the thickness of the rings is controlled by a single parameter. The idea of utilizing nonlinear variation based unit cell resulted in high absorptance ultra wide-band frequency spectrum in X-band. The proposed MMA design is three layered structure. The metamaterial nature of the proposed device is explained by simulated values of Zeff(f), µeff(f), εeff(f), and ηeff(f). The FWHM bandwidth of proposed MMA is 6.32 GHz (7.36 GHz-13.68 GHz). The fabricated MMA is ultra-thin with thickness of λo/15.3 at centre frequency 9.8 GHz. The experimental results show absorptance greater than 99% at 7.9 GHz and 11.7 GHz, covering entire X-band range makes this MMA appropriate for providing stealth technology for defense equipments by reducing radar cross section (RCS).

An Application-Based Study on Electromagnetic Absorber Using Metamaterial

“…It consists of top layer that is periodic array of unit cells, constituting MM high impedance surface, a middle layer that is lossy or lossless dielectric layer, and a bottom layer that is metal laminated ground plane. Figure 4 shows the layered structure of Layered structure of MPA [17].…”

“…a. In first step the MPA structure is placed in front of transmitting and receiving horn antennas with copper laminated ground plane of MPA structure facing the horn antennas in an anechoic chamber as shown in The two-step measuring process is used to measure absorptance for normal incidence, for variation in angle of incidence θ, and variation in E-field and H-field Real and imaginary values of (a) μeff (f) (b) εeff (f) at or within maximum absorptance frequency band [17].…”

“…The MMs find applications to realize perfect-lens [6], super-lens [7], EM cloak [10,11], EM concentrators [12], EM band gap based microwave circuit design [13], multi-band MNG resonators [14], MM-based and MM inspired efficient, electrically small antennas [15], MM-based patch and leaky-wave antennas [16], MM-based perfect absorbers [8,9,17].…”

“…Figure 6.Real and imaginary values of (a) μeff (f) (b) εeff (f) at or within maximum absorptance frequency band[17].…”