A proposed aperture coupled metamaterial mushroom antenna with inherent surface wave suppression at resonance (5.8 GHz) demonstrates over 5.41% higher measured impedance bandwidth of 8.8% and over 3.79 dBi higher gain of 5.46 dBi compared with a similar sized typical aperture coupled microstrip patch antenna, similarly fabricated. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2692–2696, 2016

A single-varactor frequency-reconfigurable microstrip patch antenna is presented. The antenna comprises a symmetrical arrangement of four metallised patches coupled and interconnected via slots and metallic bars, respectively. The antenna structure is excited through a single feed probe connected to one of the patches. To achieve a compact size of 22 � 21 � 1.57 mm, a shorting pin is placed close to the feed point to pull down the antenna's resonant frequency. By adding a varactor diode at the centre of the patch, frequency reconfigurability is introduced. Variation in the varactor's DC reverse bias voltage from 0 to 7.5 V results in a corresponding resonant frequency shift from 1000 to 1150 MHz, thus providing a tuning range of 15%. The proposed design is compact and achieves frequency reconfiguration with a singlevaractor diode and a low bias voltage requirement compared with the design characteristics reported in existing works. The antenna can find application in various existing and emerging communication systems.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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This work presents an opto-electrical method that measures the viral nucleocapsid protein and anti-N antibody interactions to differentiate between SARS-CoV-2 negative and positive nasal swab samples. Upon light exposure of the patient nasal swab sample mixed with the anti-N antibody, charge transfer (CT) transitions within the altered protein folds are initiated between the charged amino acids side chain moieties and the peptide backbone that play the role of donor and acceptor groups. A Figure of Merit (FOM) was introduced to correlate the relative variations of the samples with and without antibody at two different voltages. Empirically, SARS-CoV-2 in patient nasal swab samples was detected within two minutes, if an extracted FOM threshold of >1 was achieved; otherwise, the sample was considered negative.

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