In this paper, we propose a frequency-tunable electromagnetic absorber that uses the mechanical control of substrate thickness. The\nabsorption frequency of the proposed absorber can be changed by varying the substrate thickness. In order to mechanically control\nthe substrate thickness, we introduce a 3D-printed molding with air space. The proposed structure consists of two layers and one\nframe: the FR4 substrate, polylactic acid (PLA) frame, and air substrate. The FR4 and PLA thicknesses are fixed, and the air\nthickness is varied using the PLA frame. Therefore, the effective dielectric constant of the overall substrate can be changed. The\nmetallic rectangular patch and ground are patterned on the top and bottom FR4 substrates, respectively. The performance of the\nproposed tunable absorber is demonstrated from full-wave simulation and measurements. When both of the FR4 substrate\nthicknesses are 0.3mm and the air thickness is changed from 1 to 3.5 mm, the absorption frequency is changed from 8.9 to\n8.0 GHz, respectively. Therefore, the frequency-tuning capability of the proposed absorber is successfully demonstrated.
Loading....