Dielectric Leakage Attacks on Liquid Crystal Phase Shifters in 60 GHz WiGig Systems

ABSTRACT In this letter, the susceptibility and resilience of malicious dielectric‐leakage attacks on a liquid crystal (LC)‐based strip line phase shifter targeting 60 GHz WiGig beam‐steering applications are measured for the first time. An extreme scenario of total dielectric leakage attack, that is the cavity becoming air‐filled, is examined for two designs of the LC‐filled strip line geometry. The vulnerability assessment indicates a measured return loss increase of 10.63 dB and a characteristic impedance drift of 40.55 Ω for the design geometry that is impedance‐matched to 50 Ω at the saturated bias state of the LC. In contrast, for the design matched at the 0 V biasing state of the LC, the measured drifts are comparatively lower, with a return loss increase of 7.19 dB and the impedance variation of 28.77 Ω, featuring reduced susceptibility to dielectric leakage‐induced perturbations. Impactfully, the undesirable amplitude drifts in the transmitted signal, induced by LC leakage attacks, can significantly impact the feeding of antenna elements in beam‐steering systems. Such perturbations may lead to underestimated security vulnerabilities, including potential eavesdropping risks, particularly in mission‐critical sensing and communication applications.