Ultracompact Via-Based Absorptive Frequency-Selective Surface for 5-GHz Wi-Fi With Passbands and High-Performance Stability

A miniaturized absorptive frequency-selective surface (AFSS) allowing power transmission in other specific band is proposed in this paper. The via-based structure is adopted to make unit-cell size only 0.109λ
₀
× 0.109λ
₀
, where λ
₀
is the wavelength in free space at operating frequency. The maximum absorption rate of 99.3% locates at 5.45 GHz and half-power absorption ranges from 5.198 to 5.882 GHz, covering the whole 5-GHz Wi-Fi band. It also allows half-power transmission below 1.016 GHz. Furthermore, the absorption characteristic of the proposed AFSS is relatively stable under different backside materials, incident angles, and polarizations of incoming electromagnetic field. In addition, air vents, which are created to provide heat dissipation, make the proposed miniaturized AFSS a multifunction candidate for advanced packaging.