An Enhanced Security Lock Using A Split-Ring Resonator
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Abstract
In this paper, we present a novel approach to enhancing security in locking systems by incorporating microwave technology and split-ring resonators (SRRs). The locking mechanism exploits variations in the transmission coefficient and resonant frequency of a microwave resonator to enable secure authentication. The proposed lock is fabricated on an FR4 substrate, with a metallic SRR etched on the top layer and a coplanar waveguide (CPW) on the bottom side. By rotating the SRR to different orientations, it exhibits distinct frequency responses — each characterized by unique resonant frequencies and transmission coefficient magnitudes. As a proof of concept, we investigated two representative orientations (i.e., with the SRR gap positioned at 0° and 30°) to demonstrate the efficacy of the system. The user is required to store the initial configuration in a microcontroller. Once the security system is activated, the assembly can be removed. To disable the system, an assembly with an identical configuration must be reinserted. The microcontroller then evaluates the measured values against the original lock configuration. If the values align within a 5% tolerance range of the stored configuration, the security system is deactivated. The results show that even a slight angular variation of the SRR is sufficient to produce distinct electromagnetic signatures. Thus, with the integration of microwave technology and signal processing, this planar microwave-based locking concept has the potential to revolutionize traditional locking systems.
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References
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