Browsing by Author "Vestrum, Sarah Viola"

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    Sensitivity-enhanced Microwave Sensors for Real-time Detection and Monitoring
    (2024-05-27) Vestrum, Sarah Viola; Abbasi, Zahra; Abbasi, Zahra; Murari, Kartikeya; Badv, Maryam
    Planar microwave sensors have gained popularity due to their real-time, non-invasive sensing abilities. These structures have successfully enabled various range of applications in various applications, from small-volume liquid characterization in biomedical applications to sensing and detection in high-pressure and temperature environments. While planar resonator structures were introduced to the filter design domain first, they have transited into an ideal candidate for real-time sensing and monitoring to address different limitations that waveguide microwave sensing approaches suffer from, including bulky structures and requiring higher volumes of the sample under the test. This work focuses on enhancing the sensitivity of microwave structures using single-port reader-tag based structures. Unlike the popular two-port planar microwave sensor structures, single-port structure designs have the advantage of lowering the requirements and costs for measuring equipment, making them suitable for personalized sensing applications. Here, three single-port reader-tag based planar sensors have been introduced to enhance sensitivity and sensing distance for different rapid liquid characterization applications in the medical field. First, a patch antenna sensor for distant, small volume water-content detection. This structure detects water absorption with a resolution of 25 μL using a hydrogel-integrated sensing tag to improve sensitivity. Then, a patch antenna sensor for distant electrolyte concentration detection in urine for hydration monitoring was developed. The fabricated sensor was able to detect concentration changes of 0.5% at a distance of 24 mm from the reader, making it a well-fit candidate for wearable dehydration monitoring applications in older adults due to their increased susceptibility to dehydration.