Low-Cost UWB CPW Microwave Tattoo Sensor for Respiratory Monitoring in Epilepsy Detection

Low-Cost UWB CPW Microwave Tattoo Sensor for Respiratory Monitoring in Epilepsy Detection | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Low-Cost UWB CPW Microwave Tattoo Sensor for Respiratory Monitoring in Epilepsy Detection Hadeer Ashraf, Anwer S. Abd El-Hameed, Islam Mansour, Gehan S. Shehata This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8462764/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract This paper presents a flexible, ultra-thin, and transparent tattoo-based CPW slot microwave sensor designed for epilepsy detection based on respiratory monitoring and wearable biomedical applications. The sensor is fabricated using gold leaf on transparent PVC, enabling excellent skin conformity and long-term comfort. The proposed microwave sensor achieves an ultra-wide operating bandwidth of 2.4–17 GHz. Mechanical reliability is confirmed through bending and crumpling tests, where the sensor maintains stable impedance characteristics. In addition to respiratory monitoring, the proposed sensor is highly relevant for epilepsy detection, as epileptic seizures are often accompanied by abnormal respiratory patterns such as apnea, irregular breathing, or sudden changes in breathing rate. Continuous monitoring of respiration can therefore provide an indirect, non-invasive indicator of seizure onset and progression. Experimental measurements demonstrate clear respiratory-phase detection with an average breathing rate of approximately 27 breaths per minute (BPM), corresponding to a normal adult subject under non-pathological conditions. Safety evaluation shows that the SAR values remain well below international exposure limits. The maximum simulated SAR values of 0.946 W/kg (1 g) and 0.258 W/kg (10 g) occur at 6 GHz and a transmitted power of 20 dBm, while significantly lower SAR levels are observed at lower frequencies and power levels. With its wide bandwidth, flexibility, skin transparency, and confirmed electromagnetic safety, the proposed sensor demonstrates strong potential for continuous healthcare monitoring, epilepsy-related respiratory assessment, and future integration into unobtrusive wearable systems. Physical sciences/Engineering Health sciences/Health care Health sciences/Medical research CPW Slot Sensor Flexible UWB sensor Gold Leaf Respiratory Monitoring SAR Evaluation Tattoo Sensor Ultra-Wideband Wearable Biomedical Devices Full Text Additional Declarations No competing interests reported. Supplementary Files EthicalApproval.jpeg Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 13 Apr, 2026 Reviews received at journal 12 Apr, 2026 Reviews received at journal 06 Apr, 2026 Reviews received at journal 26 Mar, 2026 Reviewers agreed at journal 18 Mar, 2026 Reviewers agreed at journal 16 Mar, 2026 Reviewers agreed at journal 12 Mar, 2026 Reviewers invited by journal 11 Mar, 2026 Editor assigned by journal 15 Jan, 2026 Editor invited by journal 14 Jan, 2026 Submission checks completed at journal 12 Jan, 2026 First submitted to journal 12 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8462764","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":604935465,"identity":"7750cee9-3bd5-4a82-950c-26521f6b4305","order_by":0,"name":"Hadeer Ashraf","email":"","orcid":"","institution":"Benha University","correspondingAuthor":false,"prefix":"","firstName":"Hadeer","middleName":"","lastName":"Ashraf","suffix":""},{"id":604935466,"identity":"e3acf172-7435-4fce-b94a-4f6df7164c20","order_by":1,"name":"Anwer S. 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The sensor is fabricated using gold leaf on transparent PVC, enabling excellent skin conformity and long-term comfort. The proposed microwave sensor achieves an ultra-wide operating bandwidth of 2.4–17 GHz. Mechanical reliability is confirmed through bending and crumpling tests, where the sensor maintains stable impedance characteristics. In addition to respiratory monitoring, the proposed sensor is highly relevant for epilepsy detection, as epileptic seizures are often accompanied by abnormal respiratory patterns such as apnea, irregular breathing, or sudden changes in breathing rate. Continuous monitoring of respiration can therefore provide an indirect, non-invasive indicator of seizure onset and progression. Experimental measurements demonstrate clear respiratory-phase detection with an average breathing rate of approximately 27 breaths per minute (BPM), corresponding to a normal adult subject under non-pathological conditions. Safety evaluation shows that the SAR values remain well below international exposure limits. The maximum simulated SAR values of 0.946 W/kg (1 g) and 0.258 W/kg (10 g) occur at 6 GHz and a transmitted power of 20 dBm, while significantly lower SAR levels are observed at lower frequencies and power levels. 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