AbstractThe rapid development of wireless communication, space-based radar systems and active military radars in the past decades gives rise to the necessary of information security and electromagnetic waves pollution, which arouse the requirement of perfect electromagnetic absorbers in both military and civil areas. Since the isolation of graphene and the first experimental demonstration of so-called perfect metamaterial absorber carried out in the early 21st century, a large amount of research has been directed at graphene based metamaterial absorbers. This thesis delivers pioneering developments on the design of printed graphene metamaterial absorbers on electromagnetic ranges including radio frequency, microwave frequency, and THz bands. This thesis focuses on the design and optimization of broadband metamaterial absorbers for civil and military applications and aims to provide novel ideas and combed design approaches for further development of the metamaterial absorbers with outstanding properties. This thesis presents several broadband printed graphene metamaterial absorbers with competitive properties. For example, the two multilayer structure metamaterial absorbers in chapter 3 provide ultra-wide operation bandwidth covering from C band to Ka band, and from S band to Ku band, respectively; the ultra-thin metamaterial absorber in chapter 4 achieves a relative absorption bandwidth of 178% with a thickness of merely 0.3 mm; the novel printed graphene AMC based radar absorber has pioneering advances compared with conventional metallic AMC based absorbers; the genetic algorithm optimized absorber indicates potentials of coding metamaterial absorbers. For the first time, the printed graphene AMC based radar absorber is experimentally demonstrated. Furthermore, the printed graphene metamaterial absorbers presented in this thesis are angle-insensitive and polarization-independent, and possess good flexibility thanks to the printed graphene patterns and flexible dielectric substrates. This work significantly provides novel approaches and more design flexibility to metamaterial absorbers, and expands the applications of printed graphene in the design and fabrication of metamaterial absorbers.
|Date of Award
|31 Dec 2021
|Khairi Hamdi (Supervisor) & Zhirun Hu (Supervisor)