Wide Incidence Angle-Insensitive Metamaterial Absorber for Both TE and TM Polarization using Eight-Circular-Sector

Abstract

In this paper, a wide incidence angle-insensitive metamaterial absorber is proposed using eight-circular-sector (ECS). Under normal incidence, the proposed absorber shows high absorptivity at different polarizations due to its symmetric geometry. Under oblique incidence, zero-reflection conditions for transverse electric (TE) and transverse magnetic (TM) polarization are different. Nevertheless, the proposed absorber shows high absorptivity under oblique incidence of both TE and TM polarization due to ECS. The performance of the proposed absorber was demonstrated with full-wave simulation and measurements. The simulated absorptivity at the specular angles exceed 90% and the frequency variation is less than 0.7% at approximately 9.26 GHz up to a 70° incidence angle in both TM and TE polarization. We built the proposed absorber on a printed-circuit board with 20 × 20 unit cells, and we demonstrated its performance experimentally in free space. The measured absorptivity at 9.26 GHz for the specular angles is close to 98% for all polarization angles under normal incidence. As the incidence angle is varied from 0° to 70°, the measured absorptivity at 9.26 GHz for the specular angles remain above 92% in both TE and TM polarization.

Bandwidth-enhanced and Wide-angle-of-incidence Metamaterial Absorber using a Hybrid Unit Cell

“…To verify the measurement results 37 , Fig. 8(d), (e), (f), and (g) present the bistatic radar cross-section (RCS) measurement results of the copper plate and absorber prototype at the centre frequency of 10.45 GHz.…”

Recent progress in angle-insensitive narrowband and broadband metamaterial absorbers

“…Therefore, the concept has been further extended by increasing the number of patches in the circular sector topology. Nguyen and Lim have designed another narrowband absorber structure, whose unit cell geometry comprises eight circular sector patterns on the top of a grounded dielectric [37]. The properties of the substrate and metal are similar, as mentioned in the previous geometries.…”

Right-Angle Shaped Elements as Dual-Band Metamaterial Absorber in Terahertz

“…A typical expectation of an ideal absorber is its ability to render 100% absorbance at a wide range of both incidence and polarization angles of an incidence EM wave [12]. Many metamaterial absorbers with different designs and performances, for example, electric resonators [13], arrays [14], thin wire-crossed [15], crossed-shaped for bio sensing [16], bilayer [17], circular-sectors [18], metal groove features [19], slotted sectors [20], ultrathin [21], dual-band [22][23][24], and triple-band absorbers [25,26], have been studied. In addition, numerous methods are applied to control or vary the absorbance of the metamaterial device, e.g., those in [8,[27][28][29][30][31].…”