Frequency selective window blinds for indoor WLAN shielding

Abstract Securing internal wireless communication of a corporate network from external eavesdropping requires electromagnetic (EM) shielding of the whole building, which may also block useful communication bands, such as mobile phone, radio, security, and television networks. Frequency selective surfaces provide selective spatial filtering of EM signals. A dual concentric modified square loop of unit‐cell dimension , fabricated on a window blinds material with dielectric constant 1.63 is presented for shielding indoor wireless network. The design resonates at WiFi and Bluetooth frequencies of 2.4 and 5 GHz and offers a measured suppression of at least −45 dB at both the frequency bands. Simulation and experimental results have been presented which exhibit stable and polarization insensitive responses in both, transverse electric and transverse magnetic modes, as well as angular stability for oblique incident angles up to 60°. The proposed Frequency Selective Window Blinds provide on‐demand, passive EM shielding and are easy to develop, install, and use.