New compact six-band metamaterial absorber based on Closed Circular Ring Resonator (CCRR) for Radar applications

In this paper, we developed a new design of multiband perfect metamaterials absorber (MTMA) to be operated in the frequency range of 8-12 GHz. Proposed structure consists of a combination of three basic structures which is based on Closed Circular Ring Resonators (CCRR). A dielectric substrate is chosen as FR-4 material of 1.6 mm thickness and 22x22 mm size was used. The proposed (MTMA) operated at six different resonance frequencies 8.3 GHz, 9.2 GHz, 9.88 GHz, 10.66 GHz, 11.16 GHz, and 11.85 GHz with the absorption of 100 %, 100%, 98%, 91%, 98%, and 98% respectively. Negative parameters such as permittivity (epsilon) permeability (mu) reflective index (n), and impedance (z) were extracted and presented. Results indicated that the MTM absorber was found to extremely independent on the angles of polarization of the incident waves and the absorber was almost insensitive to the incident angle (0 degrees - 90 degrees) for transverse electric (TE) or transverse magnetic (TM) modes. The working principle of the structure is analyzed and illustrated through input impedance, surface current, and the electric field of the structure. The designed absorber was fabricated and experimentally measured in microwave laboratory that shows a good agreement with simulation results. According to the obtained results, the proposed metamaterials absorber is a good candidate for the military RADAR applications.