Thin multilayer frequency selective surface absorber with wide absorption response

Abstract

Design and characterization of a multilayer structure consisting of stacked frequency selective surfaces (FSS) combined with a patterned laminate absorber is presented. The FSS part is a higher order bandpass filter that operates in the C-band, namely from 5 GHz to 6 GHz. Its higher order response is achieved through the stacking of capacitive-inductive-capacitive layers to maintain the low-profile structure. The patterned absorber is glued on one side of the FSS so that the resulting structure is capable of absorbing signals in the X-band (receiving mode). The prototype has been fabricated using Taconic RF-35 substrates and Eccosorb SF for the FSS and absorber parts, respectively. It has a dimension of 24.5 cm × 24.5 cm with a thickness of 0.65 cm. The measurement has been done using free space method. The transmission loss in the passband is less than 1 dB and the roll-off slope is more than 65 dB/octave. The absorption band, characterized by its low reflection and transmission response (less than -10 dB), covers the range from 8.26 GHz to more than 12 GHz. These specifications make this prototype a promising candidate for a planar radome absorber application.