Multiband and Perfect Absorber with Circular Fishnet Metamaterial and its Variations

In this study, a composite metamaterial unit cell is introduced based on experimentally proven circular fishnet metamaterials (CF-MMs) and its stripped versions to implement an absorber for Ku band microwave regime. The offered MM absorber shows the perfect absorptivity (99.9%), the near perfect absorptivity (96.2%) and the standard absorptivity (58%) over narrow band frequencies 14.28, 14.77 and 15.2 GHz, respectively. We offered a method to create a composite metamaterial unit cell consisting of resonant type metamaterial sub-unit cells that are not suitable for absorber implementations in normal conditions. The physical mechanism behind multi-band resonances in the left-handed medium (LHM) regime is explained in detail by revealing the reverse behavior in the right-handed medium (RHM) regime keeping a single resonance feature, based on cancellation of impinging electric fields and preservation of circulating electric fields around the MM space. A detailed analysis is performed to explore and compare the power losses due to imperfect dielectric and non-ideal conductor.