We propose a tested, sensitive, and prompt COVID-19 breath screening method that takes
less than 1 min. The method is nonbiological and is based on the detection of a shift in
the resonance frequency of a nanoengineered inductor–capacitor (LC) resonant
metamaterial chip, caused by viruses and mainly related exhaled particles, when
performing terahertz spectroscopy. The chip consists of thousands of microantennas
arranged in an array and enclosed in a plastic breathalyzer-like disposable capsule kit.
After an appreciable agreement between numerical simulations (COMSOL and CST) and
experimental results was reached using our metamaterial design, low-scale clinical
trials were conducted with asymptomatic and symptomatic coronavirus patients and healthy
individuals. It is shown that coronavirus-positive individuals are effectively screened
upon observation of a shift in the transmission resonance frequency of about
1.5–9 GHz, which is diagnostically different from the resonance shift of healthy
individuals who display a 0–1.5 GHz shift. The initial results of screening
coronavirus patients yielded 88% agreement with the real-time quantitative polymerase
chain reaction (RT-qPCR) results (performed concurrently with the breath test) with an
outcome of a positive predicted value of 87% and a negative predicted value of 88%.
This experimental study reports a systematic investigation of Safe Operating Area limits in AlGaN/GaN HEMT using sub-μs pulse characterization with on the fly Raman and CV characterization to probe defect and stress evolution across the device. Influence of a recess depth on SOA boundary is analyzed. Post failure analysis corroborates well with the failure physics unveiled in this work.
LC‐circuit‐based resonant metamaterials (MM) operating in the terahertz (THz) are proven to detect the presence of nanoparticles within the capacitive gap of nanoantennas, manifesting a red‐shift in the resonance frequency. Sensitivity reduction (reduced red‐shift) due to the interaction/coupling of the substrate's Fabry–Pérot (FP) oscillations with the MM resonance is discussed. This new discovery of coupling is more probable and intense in thicker semiconductor substrates used in standard complementary metal‐oxide semiconductor processes, due to the high density of the FP oscillations and thus the probability for coupling with the single MM resonance increases. This also results in reducing the quality factor (Q‐Factor) of MM resonance, as well as the dielectric response to nanoparticles spread on the MM surface, by reducing the resonance frequency shift (ΔF) and thus the sensitivity of resonant MM. A sensitivity restoration of the MM resonance's red‐shift by decoupling it from the FP oscillations after thinning down the substrate by standard backside polishing is shown. The research is based on a combination of rigorous CST system‐level simulations along with THz impedance spectroscopy laboratory experiments: up to a fivefold enhancement of sensitivity of the thinned substrate compared with the conventional thick substrates is shown. This work has potential applications in the high‐sensitivity detection of nanomaterials and bio‐sensing at ultra‐low concentrations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.