In this paper, the development and designing of angle-independent metamaterial microwave absorbers are presented. The unit cell consists of two concentric circle that are linked by consolidated resistors. The absorber is built on a dielectric substrate (FR4) with a thickness of 3.2 mm (λ/0.07) and a dielectric constant of 4.3. The wideband absorption is acquired in the range of 2.8 to 10.42 GHz with a wide band of 7.62 GHz with absorptivity above 90%. In the area of interest, a flat band is obtained, and to examine the current distribution and electric field in the respective region, two peaks are considered at a frequency of 3.66 and 9.54 GHz, with maximum absorptivity of 99.99% and 99.44%, respectively. The presented absorber is examined under different angles for phi and theta variation. From the phi variation, it is observed that for all the angles, absorptivity does not vary, which confirms that the absorber is acting as an angle independent. The fabricated sheet consists of an array of a unit cell, which is examined inside the anechoic chamber with the help of two horn antennas and vector network analyzer. The tested and simulated results are compared, and it was observed that they are close in their agreement. At the end of the manuscript, the presented and already reported arts are compared, and it is observed that the presented one operates for the low frequency with higher bandwidth. The presented absorber can be practically used for defense applications for Radar Cross Sections reduction.

In this article, an angle-independent wideband metamaterial microwave absorber (MMA) for C (4–8 GHz) and X (8–12 GHz) band frequency is presented. The unit cell of the proposed MMA consists of outer and inner structure associated with lumped resistors. The outer structure consists of rectangular split-ring resonator, whereas the inner structure consists of circular split-ring resonator. The structure is made up of three layers, in which top and bottom layers are made up of copper acting as a conducting material. The middle layer is made up of FR-4 acting as a dielectric substrate. The resonating structure at the top is designed in such a way that wideband absorption is achieved in the range from 6.11 to 13.52 GHz. The wideband absorption within the range approaches almost unity having a bandwidth of 7.41 GHz. Three different peaks are considered in the range of interest having maximum absorption of 0.94, 0.94, and 0.99 at frequencies of 6.76, 11.15, and 13.07 GHz, respectively. The structure is analyzed with respect to the effective parameters, i.e., effective permittivity (${\varepsilon _{{\textrm{eff}}}}$) and effective permeability (${\mu _{{\textrm{eff}}}}$), to prove that the structure acts as a metamaterial. Electric field and current distribution are plotted at three different peaks to prove the mechanism of wideband absorption. Normal and oblique incidence are plotted to determine that the structure is behaving as an angle independent. The simulated structure is fabricated on FR-4 substrate and measured inside an anechoic chamber. Finally, to prove the novelty of the work, the proposed structure is compared with the already reported MMA. The proposed MMA finds practical applications in radar cross section reduction, terrestrial communication, keyless entry system, space communication, radar, and baby monitor.