Fabrication and evaluation of electromagnetic wave absorbers using frequency selective surface

The electromagnetic wave absorption mechanism of conductorbacked electromagnetic wave absorbers with periodically arranged conductor patterns on the surface layer (pattern absorbers) was investigated. The pattern absorbers in this work were composed of a patterned layer acting as a frequency selective surface, such that the pattern served as a resonator together with a back reflector. Electromagnetic wave simulations predicted that the absorption characteristics of these devices could be tuned by varying the shape, alignment, and occupied area ratio of the pattern conductor so as to match the surface impedance to that of the free space. Pattern absorbers based on this design and operating at 2.45 GHz were designed and fabricated and their absorption characteristics were evaluated. The experimental results were found to agree with the theoretical predictions.