Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas
Painless, cuffless and continuous blood pressure monitoring sensors provide a more dynamic measure of blood pressure for critical diagnosis or continuous monitoring of hypertensive patients compared to current cuff-based options. To this end, a novel flexible, wearable and miniaturized microstrip pa...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-05-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/11/3996 |
| _version_ | 1797491775954223104 |
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| author | Mona K. El Abbasi Mervat Madi Herbert F. Jelinek Karim Y. Kabalan |
| author_facet | Mona K. El Abbasi Mervat Madi Herbert F. Jelinek Karim Y. Kabalan |
| author_sort | Mona K. El Abbasi |
| collection | DOAJ |
| description | Painless, cuffless and continuous blood pressure monitoring sensors provide a more dynamic measure of blood pressure for critical diagnosis or continuous monitoring of hypertensive patients compared to current cuff-based options. To this end, a novel flexible, wearable and miniaturized microstrip patch antenna topology is proposed to measure dynamic blood pressure (BP). The methodology was implemented on a simulated five-layer human tissue arm model created and designed in High-Frequency Simulation Software “HFSS”. The electrical properties of the five-layer human tissue were set at the frequency range (2–3) GHz to comply with clinical/engineering standards. The fabricated patch incorporated on a 0.4 mm epoxy substrate achieved consistency between the simulated and measured reflection coefficient results at flat and bent conditions over the frequency range of 2.3–2.6 GHz. Simulations for a 10 g average specific absorption rate (SAR) based on IEEE-Standard for a human arm at different input powers were also carried out. The safest input power was 50 mW with an acceptable SAR value of 3.89 W/Kg < 4W/Kg. This study also explored a novel method to obtain the pulse transit time (PTT) as an option to measure BP. Pulse transmit time is based on obtaining the time difference between the transmission coefficient scattering waveforms measured between the two pairs of metallic sensors underlying the assumption that brachial arterial geometries are dynamic. Consequently, the proposed model is validated by comparing it to the standard nonlinear Moens and Korteweg model over different artery thickness-radius ratios, showing excellent correlation between 0.76 ± 0.03 and 0.81 ± 0.03 with the systolic and diastolic BP results. The absolute risk of arterial blood pressure increased with the increase in brachial artery thickness-radius ratio. The results of both methods successfully demonstrate how the radius estimates, PTT and pulse wave velocity (PWV), along with electromagnetic (EM) antenna transmission propagation characteristics, can be used to estimate continuous BP non-invasively. |
| first_indexed | 2024-03-10T00:54:06Z |
| format | Article |
| id | doaj.art-b1daad6349364b30aec487573bae86f5 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T00:54:06Z |
| publishDate | 2022-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-b1daad6349364b30aec487573bae86f52023-11-23T14:47:01ZengMDPI AGSensors1424-82202022-05-012211399610.3390/s22113996Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch AntennasMona K. El Abbasi0Mervat Madi1Herbert F. Jelinek2Karim Y. Kabalan3Electrical and Computer Engineering Department, American University of Beirut, Beirut 1107 2020, LebanonElectrical and Electronics Engineering School Department, Amity University Dubai, Dubai P.O. Box 345019, United Arab EmiratesBiomedical Engineering Department and Health Innovation Engineering Center, Biotechnology Center, Khalifa University of Science and Technology, Abu Dhabi P.O. Box 127788, United Arab EmiratesElectrical and Computer Engineering Department, American University of Beirut, Beirut 1107 2020, LebanonPainless, cuffless and continuous blood pressure monitoring sensors provide a more dynamic measure of blood pressure for critical diagnosis or continuous monitoring of hypertensive patients compared to current cuff-based options. To this end, a novel flexible, wearable and miniaturized microstrip patch antenna topology is proposed to measure dynamic blood pressure (BP). The methodology was implemented on a simulated five-layer human tissue arm model created and designed in High-Frequency Simulation Software “HFSS”. The electrical properties of the five-layer human tissue were set at the frequency range (2–3) GHz to comply with clinical/engineering standards. The fabricated patch incorporated on a 0.4 mm epoxy substrate achieved consistency between the simulated and measured reflection coefficient results at flat and bent conditions over the frequency range of 2.3–2.6 GHz. Simulations for a 10 g average specific absorption rate (SAR) based on IEEE-Standard for a human arm at different input powers were also carried out. The safest input power was 50 mW with an acceptable SAR value of 3.89 W/Kg < 4W/Kg. This study also explored a novel method to obtain the pulse transit time (PTT) as an option to measure BP. Pulse transmit time is based on obtaining the time difference between the transmission coefficient scattering waveforms measured between the two pairs of metallic sensors underlying the assumption that brachial arterial geometries are dynamic. Consequently, the proposed model is validated by comparing it to the standard nonlinear Moens and Korteweg model over different artery thickness-radius ratios, showing excellent correlation between 0.76 ± 0.03 and 0.81 ± 0.03 with the systolic and diastolic BP results. The absolute risk of arterial blood pressure increased with the increase in brachial artery thickness-radius ratio. The results of both methods successfully demonstrate how the radius estimates, PTT and pulse wave velocity (PWV), along with electromagnetic (EM) antenna transmission propagation characteristics, can be used to estimate continuous BP non-invasively.https://www.mdpi.com/1424-8220/22/11/3996miniaturized microstrip patch antennatransmission coefficient scattering parameterspecific absorption rateMoens-Korteweg equationbrachial artery radius-to-tissue thickness ratioblood pressure |
| spellingShingle | Mona K. El Abbasi Mervat Madi Herbert F. Jelinek Karim Y. Kabalan Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas Sensors miniaturized microstrip patch antenna transmission coefficient scattering parameter specific absorption rate Moens-Korteweg equation brachial artery radius-to-tissue thickness ratio blood pressure |
| title | Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas |
| title_full | Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas |
| title_fullStr | Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas |
| title_full_unstemmed | Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas |
| title_short | Wearable Blood Pressure Sensing Based on Transmission Coefficient Scattering for Microstrip Patch Antennas |
| title_sort | wearable blood pressure sensing based on transmission coefficient scattering for microstrip patch antennas |
| topic | miniaturized microstrip patch antenna transmission coefficient scattering parameter specific absorption rate Moens-Korteweg equation brachial artery radius-to-tissue thickness ratio blood pressure |
| url | https://www.mdpi.com/1424-8220/22/11/3996 |
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