Smartphone Frequency Shielding With Penta-Bandstop FSS for Security and Electromagnetic Health Applications

In this paper, a novel penta-bandstop frequency-selective surface (FSS) is proposed to shield the frequencies used in smartphone/tablet for security and electromagnetic health applications. It can be used to provide wireless security and protection against unwanted electromagnetic radiation. The novelty of the proposed structure lies in the five stopbands, which can be used for communication, viz., GSM, GPS, Bluetooth/Wi-Fi, Wi-MAX, and WLAN. The FSS unit cell consists of a square patch surrounded by five thin modified rectangular rings etched over a one-sided FR4 substrate. Size of the unit cell is 0.135 λ × 0.135 λ, corresponding to the lowest operating frequency. To validate the proposed FSS, a prototype is fabricated and measured. Measured and simulated results are presented for the fabricated prototype. Stable frequency responses are achieved under oblique incidence for the transverse electric as well as transverse magnetic polarizations.