Secure Electromagnetic Buildings Using Slow Phase-Switching Frequency-Selective Surfaces

Abstract

The concept of a secure electromagnetic building (SEB) which can successfully prohibit wireless communications is presented. Wireless security is achieved using a slow phaseswitching technique and can be realized by time-varying the transmission properties of a frequency-selective surface (FSS) to increase the bit error rate (BER) of the unwanted signal. Results are presented which demonstrate that a technique of phase switching at rates much lower than the baseband data rate can be used successfully. The system has been implemented using a reconfigurable dual-polarized dual layer FSS incorporating varactor diodes where over 100 • of phase change can be achieved for voltage changes of ±0 − 3V . A vector signal analyzer was used to evaluate the BER performance of the system for a GSM signal operating at 2 GHz. BERs are shown to be as high as 36% which are sufficient to successfully prohibit wireless communication. The solution is also shown to be robust over a wide range of incidence angles, which is important for real-world applications where the location of the prohibited wireless source may be unknown or mobile. Furthermore, as the system is reconfigurable, the building can be switched between secure and nonsecure modes.

Direct Antenna Modulation for High-Order Phase Shift Keying

“…This is due to the known deficiency in diode modelling for FSS applications, as manufacturer models are based on diodes being applied in microstrip transmission lines, rather than being embedded in an FSS orthogonal to the direction of power flow. Similar effects can be seen in [44]. All the crosspolar components produced within these beamwidths are at least 14.2dB below the co-polar magnitude at that angle.…”

Frequency Selective Surfaces: A Review

“…FSSs have been used in various applications ranging in different frequency bands from RF, micro-, millimeter wave, and terahertz regions [97,114,115]. Some of the researches are well demonstrated in radio frequency identifications [9,116], wireless communications [117,118], shielding purposes/EMI/EMC problems [58,81,82,119], polarization transformation [120], stealth radomes [75,98,103,121], EMI protection from portable electronics/wireless charging pad [122,123], directional multi-band antenna [124], polarization detection [125], and sensing [28,126]. Although a diverse categorization of FSSs can be made based on their applications, here we investigate six types of FSSs in this survey including microwave absorbers, active FSSs, wearable FSS, meta-skin FSS, optical FSS, and textile FSSs.…”

Practical absorptive frequency selective surface based on printed electronics technology for radome applications

“…Frequency selective surfaces (FSSs) are electromagnetic (EM) structures that periodically arrange conductive patterns or dielectrics having the same shape to selectively reflect or transmit certain frequencies using the same phase current that has been induced by an incident electromagnetic wave . The properties of this kind of spatial filter are utilized and studied in various fields, such as improving the communications environment within a building by blocking interference signals (enhancement of spectral efficiency in buildings), ensuring EM compatibility to control the EM interference waves between heterogeneous devices, and achieving stealth technology to minimize the possibility of detection by enemy radar during war …”