Ultra-wideband microwave absorber based on uncharged graphene layers

ABSTRACT

In this paper, a novel method is presented to increase microwave absorbers bandwidth. The proposed method is based on coupling resonators which consist of a graphene layer at the top, a dielectric spacer and a metallic plate in the bottom. The first resonance frequency of every resonator is calculated by the thickness and relative permittivity of the substrate and the next harmonics are odd coefficients of the first resonance. Absorption rate growth is based on the electric field reinforcement in the graphene plane via tuning graphene Fermi energy. Finally, after combining the resonators and by considering reflection amplitude lower than −10 dB, a bandwidth of 11.9 GHz is obtained from 5.3 to 17.2 GHz for Fermi energy equal to zero. Low-profile and wideband absorption of the proposed structure can be effectively used in radar cross-section applications.

KEYWORDS:

• Ultra-wideband microwave absorber
• Fermi energy
• graphene conductivity
• surface plasmons

Acknowledgments

The authors would also like to thank the reviewers for their valuable comments and suggestions, which helped improve the quality of the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been supported by Semnan University.

Notes on contributors

Mohammad Mahdi Ghods

Mohammad Mahdi Ghods received the MS degree from Semnan University, Semnan, Iran, in 2018. Her current research interests include contribution to the study of wideband microwave absorbers, radar cross-section reduction, graphene-based optical sensors and plasmonic nano structures.

Pejman Rezaei

Pejman Rezaei is associate professor in the Semnan University, Semnan, Iran. His current research interests are Electromagnetics theory, Antenna theory and design, SIW structure, Reconfigurable antenna, metamaterial structure, and satellite communication.