Many researchers are studying electromagnetic wave absorbers. This is mainly due to the large number of existing wireless systems. The absorbers find numerous applications, from commercial to military systems. Allied to this, also the interest in Frequency Selective Surfaces (FSS), which are, basically, spatial filters, grows. Thus, this work proposes the use of FSS to design electromagnetic absorbers. In this study, Altair FEKO software was used. A parametric analysis is presented, demonstrating the understanding of the physical dimensions' effects. A prototype is built to validate the analysis performed. A good agreement between the numerical and experimental results is observed. Furthermore, measured results show that the absorber panel suppresses reflection (below-10 dB) from 1.97 GHz to 3.15 GHz, covering the entire ISM band.

Frequency Selective Surfaces (FSS) are increasingly being used in telecommunications systems due to the numerous advantages presented by this sort of structure, among them low cost, ease of fabrication, and low profile stand out. This work reports the design, fabrication, and characterization of a multilayer frequency-selective absorber (FSA) for broadband operation. The proposed structure shows an absorption performance (operating in the frequency range between 2 GHz and 6 GHz) within the transmission band. The absorber consists of cascaded frequency selective surfaces, which are composed of both conductive square loops, which reflect incident signals, and resistive ones, which act as an absorbing layer. To verify the absorbing structure performance, full-wave numerical simulations and measurements are presented. The measured results are in good agreement with the numerical ones and show that the design performs absorption above 80% within the range of 2.48 GHz to 6.13 GHz, which verifies the project properties. Besides that, numerical results show that the proposed absorber has a proper response under oblique incidence up to 30 • .

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