Characterization of Electromagnetics Wave Absorber Composed of Ring Resonator Structure

In absorbent applications, the technology of surface textured is often used to reduce the material thickness thus allowing the realization of thinner materials. In order to obtain high absorption rate of electromagnetics (EM) wave absorber at the desired frequency, a metal patch upon the wave absorber can be made in a specific shape. In this paper, a characterization of EM wave absorber composed of ring resonator structure is carried out by incorporating resistors between the ring resonator structures on two types of boundary condition, namely perfect electric conductor (PEC) and perfect magnetic conductor (PMC) to represent an infinite double periodic arrangement, and the radiation boundary to analyze the performance of proposed EM wave absorber in an actual condition. By using an FR4 epoxy dielectric substrate with the thickness of 1.6 mm, the proposed EM wave absorber is constructed by two-dimensional array of unit cells. Meanwhile, each unit cell has the dimension of 22 mm × 22 mm and is composed of a couple of ring resonator structures in a symmetrical configuration. Based on parametric studies, the resistor value required to be incorporated into the structure is in the range of 1 kΩ to 6 kΩ. The characterization result shows that the absorption rate of proposed EM wave absorber is −23.41 dB on the PEC and PMC boundaries with the resistor value of 6 kΩ, and −18.3 dB on the radiation boundary with the resistor value of 5.6 kΩ at the frequency of 2.45 GHz.