Hybrid Absorber With Dual-Band Performance and High Absorption Rate

Low-profile absorbers are of interest for compact shielded enclosures for making antenna measurements. Furthermore, the cost should be minimized for practical systems since massive production is required. In this work, a novel dual-band hybrid absorber based on structured resonators and lossy dielectric material is proposed to meet these requirements. The lossy material enables improvement in the absorption rate and operating bandwidth. The proposed absorber operates at 2.4- and 5.0-GHz Wi-Fi spectra and covers the low-frequency bands with a reflection coefficient lower than
$-$
25 dB and a large part of the high-frequency ones with reflection lower than
$-$
20 dB. Moreover, some of the Wi-Fi bands are covered with a reflection coefficient better than
$-$
30 dB. In order to validate the proposed concept, the dual-band absorber is manufactured and tested, and the agreement between the simulation and measurement results is good. The presented structure is cost-effective since it only uses conventional printed circuit board (PCB) technology for manufacturing and commercial lossy dielectric material.