Dual-Band Frequency Absorber Based on Split-Ring Resonators for WiMAX and WLAN Bands

Abstract

In this paper, a dual-band compact absorber design based on split-ring resonator for WiMAX and WLAN bands is presented. Top plate of a unit cell in the proposed design is composed of three concentric circular split ring (SR) elements covers an area of π×13.42 mm 2 and placed on a FR4 substrate with 1.5 mm thickness, dielectric constant of 4.3 and loss tangent of 0.025. Also, six miniature metallic loadings are appropriately inserted between the SR elements. The back side of the substrate is covered full ground plane for shielding transmission from port 1 to port 2. In the design, SR elements are primary resonator of the proposed absorber and provide a dual band of absorption at the respective frequencies. The metallic loadings are used for fine frequency tuning where the absorption peaks occur. Hence, the absorption frequency of the design can be easily tuned by means of sliding the loadings between the rings without changing any design parameters. The proposed compact absorber excited by incident electromagnetic wave provides 0.92 and 0.97 absorption peaks at 3.52 GHz WiMAX and 5.16 GHz WLAN bands, respectively. The design and analysis of the absorber are performed by means of CST Microwave Studio based on frequency domain solver. In this paper, the absorber design with novel configuration is introduced in detail and its corresponding electric field distributions and absorption characteristics at the related bands are presented. Also, the proposed SRR-based absorber design is compared with the previously reported dual or multi bands absorbers in terms of dimensions, resonance frequencies and number of bands.