Absorbing property of MnO2 nanorods and its meta-surface design

Abstract

MnO2 nanorods were prepared by using the hydrothermal method and freeze-drying technology, and then molded into the MnO2/paraffin circular samples in different filling concentrations. The crystalline phase, microstructure and electromagnetic parameters of the samples were characterized and tested by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and vector network analyzer (VNA). Sample meta-surface was designed and simulated by CST software and the pre and post simulation calculation and research of the meta-surface were carried out. The results show that prepared MnO2 powder has a rod structure with the diameter and length of the rod about 50-100 nm, 5-10 μm, respectively. The single cylindric structure is well-shaped, and the overall structure is homogeneous with crystallinity. Moreover, the tangent of dielectric loss(tanδ) increases with concentration, making a great contribution to the electromagnetic attenuation coefficient (α) of the sample of MnO2/paraffin, which increases with filling concentration of MnO2 nanorods. Microwave absorption frequency domain of MnO2/paraffin material is significantly broadened by the design of meta-surface, namely, the optimal bandwidth in 2-18 GHz can reach 14.32 GHz. The reason is the superposition of absorption peaks over a specified frequency range, which is caused by the coexistence of multiple resonances of the meta-surface.

Keywords

• hydrothermal method
• mno2 nanorod
• absorbing mechanism
• meta-surface