Textile-based quad-band electromagnetic absorber design for wearable applications

Abstract

In this article, a textile-based quad-band electromagnetic absorber (TQA) is presented for wearable applications in the S-band frequency region. The proposed TQA consists of two asymmetric X-shaped resonators (AXRs) with different arm lengths placed on fully grounded denim fabric. Since each arm of the two AXRs excites a different resonance mode, four distinctive absorption bands can be achieved by adjusting the arm lengths. The proposed structure with optimal design parameters, designed and optimized using CST Microwave Studio Suite v.2021, provides over 0.99 absorption peaks at 2.68, 2.80, 3.00, and 3.18 GHz frequencies in the simulation environment. Also, an efficient lumped equivalent circuit model is extracted for the absorber to demonstrate the principle of the quad-band operation in the respective frequencies. In addition, a good agreement between simulated and measured results is observed and thus the numerical design is validated. More importantly, to the best of the authors’ knowledge, this is the first textile based absorber design that provides absorbance in four different frequency bands.