Design of Broadband Microwave Absorber using Double Split-Ring Resonators
Recently increasing attention has been paid to electromagnetic absorbers due to their wide applications such as light harvesting, electromagnetic interference shielding and stealth technology in military. Generally, absorbers are required to have strong absorption, wide bandwidth and light weight. For traditional microwave absorber, the microwave absorbing performance is closely related to permeability and permittivity of composites. In current research, Artificial EM structures, has been utilized for microwave absorption, because of the absorption performance can be easily improved and controlled by adjusting the shape, the size and period of AEM structures.
In this paper, the design, simulation, fabrication, and measurement of broadband microwave absorber based on a Artificial EM structure are presented. The Artificial EM structure consists double split-ring resonators and metal ground plane separated by three lossy dielectric substrates. The effects of design parameters on microwave absorption were studied, including the size and period of AEM structures, EM parameters and thickness of dielectric substrate. Moreover, the effects of incidence angles for transverse electromagnetic (TE) and transverse magnetic (TM) waves on the reflection loss of RAS were also investigated. Numerical simulations indicate that the microwave absorbing properties of RAS can be improved by adjusting the unit cell parameters, thickness and EM parameters of substrate. Optimized microwave absorbers based on AEM structures is broadband and show absorption in C, X and Ku band. Optimized microwave absorbers were fabricated using photolithography and their return loss was measured in anechoic chamber.
Keywords - Microwave Absorbers, Meta Materials, Radar Cross Section, Photolithography.