Numerical Research On Tunable Metamaterial Absorber

In order to improve the ability of the equipment to survive and penetration capability, the military powers around the world have launched a study on stealth technology. The electromagnetic wave absorbers also have many civil applications such as information propagation,electromagnetic shield and defense for microwave radiation. Thus it is very important to investigate the absorption ability of the new materials.Metamaterial absorbers have been extensively studied for reducing the electromagnetic wave reflections for a variety of applications, ranging from stealth technology to anechoic chambers. In this paper, based on the numerical simulation method and existed research results of the absorbing metamaterials, we have designed two kinds of metamaterial absorber structure, i.e., the ring type microwave electric resonant structure and the tunable metamaterial absorber structure. We use the transfer matrix method to simulate numerically the transmission properties of the metamaterials. There is also a significant amount of numerical work in which the complex transmission and reflection amplitudes are calculated for a finite thickness of metamaterial. The absorption properties of the two absorbing structures mentioned above and the effects of the metamaterial structure parameters in each absorber on the wave absorption properties in the microwave frequency range are investigated and simulated using a numerical simulation method. Main results include:1. A single unit cell layer demonstrates a peak A(ω) greater than 91.3% at 10.2 GHz. For the multi-layer metamaterial assembly, the absorption peak value reaches nearly 100% at 9.72GHz.2. Study shows that the Electric ring resonator (ERR) has also an electric response. The electric response of the ERR is demonstrated by closing the air gap, and therefore destroying the resonance condition.3. The magnetic response originates from the combination of the center wire of the ERR with a cut wire separated by a substrate. The electric resonance comes from the edge effect of ERR surface currents, and the electric response of the cut wire. The size of the ERR gap can tune the electric resonance.4. Studies suggest that by adjusting the length and width of the ERR split or substrate parameters , the resonance frequency will change,and the absorption band could be tuned.