Vol. 116
Latest Volume
All Volumes
PIERB 116 [2026] PIERB 115 [2025] PIERB 114 [2025] PIERB 113 [2025] PIERB 112 [2025] PIERB 111 [2025] PIERB 110 [2025] PIERB 109 [2024] PIERB 108 [2024] PIERB 107 [2024] PIERB 106 [2024] PIERB 105 [2024] PIERB 104 [2024] PIERB 103 [2023] PIERB 102 [2023] PIERB 101 [2023] PIERB 100 [2023] PIERB 99 [2023] PIERB 98 [2023] PIERB 97 [2022] PIERB 96 [2022] PIERB 95 [2022] PIERB 94 [2021] PIERB 93 [2021] PIERB 92 [2021] PIERB 91 [2021] PIERB 90 [2021] PIERB 89 [2020] PIERB 88 [2020] PIERB 87 [2020] PIERB 86 [2020] PIERB 85 [2019] PIERB 84 [2019] PIERB 83 [2019] PIERB 82 [2018] PIERB 81 [2018] PIERB 80 [2018] PIERB 79 [2017] PIERB 78 [2017] PIERB 77 [2017] PIERB 76 [2017] PIERB 75 [2017] PIERB 74 [2017] PIERB 73 [2017] PIERB 72 [2017] PIERB 71 [2016] PIERB 70 [2016] PIERB 69 [2016] PIERB 68 [2016] PIERB 67 [2016] PIERB 66 [2016] PIERB 65 [2016] PIERB 64 [2015] PIERB 63 [2015] PIERB 62 [2015] PIERB 61 [2014] PIERB 60 [2014] PIERB 59 [2014] PIERB 58 [2014] PIERB 57 [2014] PIERB 56 [2013] PIERB 55 [2013] PIERB 54 [2013] PIERB 53 [2013] PIERB 52 [2013] PIERB 51 [2013] PIERB 50 [2013] PIERB 49 [2013] PIERB 48 [2013] PIERB 47 [2013] PIERB 46 [2013] PIERB 45 [2012] PIERB 44 [2012] PIERB 43 [2012] PIERB 42 [2012] PIERB 41 [2012] PIERB 40 [2012] PIERB 39 [2012] PIERB 38 [2012] PIERB 37 [2012] PIERB 36 [2012] PIERB 35 [2011] PIERB 34 [2011] PIERB 33 [2011] PIERB 32 [2011] PIERB 31 [2011] PIERB 30 [2011] PIERB 29 [2011] PIERB 28 [2011] PIERB 27 [2011] PIERB 26 [2010] PIERB 25 [2010] PIERB 24 [2010] PIERB 23 [2010] PIERB 22 [2010] PIERB 21 [2010] PIERB 20 [2010] PIERB 19 [2010] PIERB 18 [2009] PIERB 17 [2009] PIERB 16 [2009] PIERB 15 [2009] PIERB 14 [2009] PIERB 13 [2009] PIERB 12 [2009] PIERB 11 [2009] PIERB 10 [2008] PIERB 9 [2008] PIERB 8 [2008] PIERB 7 [2008] PIERB 6 [2008] PIERB 5 [2008] PIERB 4 [2008] PIERB 3 [2008] PIERB 2 [2008] PIERB 1 [2008]
2026-01-01
Microstrip Array Antenna Design for a 24 GHz Radar-Based Vital Signs Monitoring System
By
Progress In Electromagnetics Research B, Vol. 116, 94-106, 2026
Abstract
Non-contact vital signs monitoring using radar technology has become increasingly important in modern healthcare, as it enables continuous physiological measurement without direct skin contact, minimizing patient discomfort and the risk of infection. To address these needs, this study presents the design and analysis of a 24 GHz microstrip array antenna developed for a radar-based vital signs monitoring system. Array configurations consisting of one to five circular patch elements were analyzed to optimize reflection coefficient, gain, and radiation characteristics, aiming to achieve high sensitivity, compactness, and safety for biomedical radar applications. Simulation results indicate that the four-element array achieves optimal performance, with a reflection coefficient of -39.27 dB, gain of 5.29 dBi, and bandwidth of 1.35 GHz at 24 GHz. To evaluate electromagnetic safety, Specific Absorption Rate (SAR) analysis using a three-layer human tissue model (skin, fat, and muscle) yielded values of 0.637 W/kg (1 g) and 0.205 W/kg (10 g) at a 50 mm separation distance, both within ICNIRP and FCC limits. Furthermore, bending simulations with curvature radii of 5 mm, 15 mm, and 50 mm confirmed stable impedance matching and minimal frequency variation, demonstrating strong mechanical flexibility. Overall, the proposed antenna exhibits high gain, reliable performance, and safety compliance, making it suitable for integration into portable radar-based medical devices for continuous and contactless monitoring of heart rate and respiration.
Citation
Murtini Murtini, Nurhayati Nurhayati, Usman Rizqi Iman, Fitri Yuli Zulkifli, Dewiani Dewiani, and Lilik Anifah, "Microstrip Array Antenna Design for a 24 GHz Radar-Based Vital Signs Monitoring System," Progress In Electromagnetics Research B, Vol. 116, 94-106, 2026.
doi:10.2528/PIERB25101302
References

1. Alzahrani, M. S., A. H. Albishi, A. E. Alfaifi, A. M. Alzahrani, R. I. Aldoosary, S. Y. Alshabeeb, A. A. Alammar, B. M. Alalrashidi, E. M. Zoqeei, and O. A. Kofiyah, "Vital signs role and significance in detecting early cardiac events," International Journal of Community Medicine And Public Health, Vol. 11, No. 1, 419-423, Dec. 2023.
doi:10.18203/2394-6040.ijcmph20233847        Google Scholar

2. Yu, Yang, Bhavya Jain, Gautam Anand, Mahdi Heidarian, Andrew Lowe, and Anubha Kalra, "Technologies for non-invasive physiological sensing: Status, challenges, and future horizons," Biosensors and Bioelectronics: X, Vol. 16, 100420, 2024.
doi:10.1016/j.biosx.2023.100420        Google Scholar

3. Shuzan, Md. Nazmul Islam, Moajjem Hossain Chowdhury, Md. Shafayet Hossain, Muhammad E. H. Chowdhury, Mamun Bin Ibne Reaz, Mohammad Monir Uddin, Amith Khandakar, Zaid Bin Mahbub, and Sawal Hamid Md. Ali, "A novel non-invasive estimation of respiration rate from motion corrupted photoplethysmograph signal using machine learning model," IEEE Access, Vol. 9, 96775-96790, 2021.
doi:10.1109/access.2021.3095380        Google Scholar

4. Tiwari, Shamik, Anurag Jain, Akhilesh Kumar Sharma, and Khaled Mohamad Almustafa, "Phonocardiogram signal based multi-class cardiac diagnostic decision support system," IEEE Access, Vol. 9, 110710-110722, 2021.
doi:10.1109/access.2021.3103316        Google Scholar

5. Ghosh, Sudipta, Bhabani Prasad Chattopadhyay, Ram Mohan Roy, Jayanta Mukherjee, and Manjunatha Mahadevappa, "Non-invasive cuffless blood pressure and heart rate monitoring using impedance cardiography," Intelligent Medicine, Vol. 2, No. 04, 199-208, 2022.
doi:10.1016/j.imed.2021.11.001        Google Scholar

6. Li, Sha, Lina Zhao, Bei Zhang, Yao Yuan, Hongjuan Cao, and Zhenqiu Yu, "Ultrasound cardiogram-based diagnosis of cardiac hypertrophy from hypertension and analysis of its relationship with expression of autophagy-related protein," Annals of Palliative Medicine, Vol. 11, No. 2, 68494-68694, 2022.
doi:10.21037/apm-21-3936        Google Scholar

7. Xu, Hongqiang, Malikeh P. Ebrahim, Kareeb Hasan, Fatemeh Heydari, Paul Howley, and Mehmet Rasit Yuce, "Accurate heart rate and respiration rate detection based on a higher-order harmonics peak selection method using radar non-contact sensors," Sensors, Vol. 22, No. 1, 83, 2022.
doi:10.3390/s22010083        Google Scholar

8. Shan, Jingfeng, Karumudi Rambabu, Yang Zhang, and Jun Lin, "High gain array antenna for 24 GHz FMCW automotive radars," AEU --- International Journal of Electronics and Communications, Vol. 147, 154144, 2022.
doi:10.1016/j.aeue.2022.154144        Google Scholar

9. Arasteh, Emad, Esther S. Veldhoen, Xi Long, Maartje van Poppel, Marjolein van der Linden, Thomas Alderliesten, Joppe Nijman, Robbin de Goederen, and Jeroen Dudink, "Ultra-wideband radar for simultaneous and unobtrusive monitoring of respiratory and heart rates in early childhood: A deep transfer learning approach," Sensors, Vol. 23, No. 18, 7665, 2023.
doi:10.3390/s23187665        Google Scholar

10. Antolinos, Elías and Jesús Grajal, "Comprehensive comparison of continuous-wave and linear-frequency-modulated continuous-wave radars for short-range vital sign monitoring," IEEE Transactions on Biomedical Circuits and Systems, Vol. 17, No. 2, 229-245, 2023.
doi:10.1109/tbcas.2023.3257647        Google Scholar

11. Tzou, Shiow-Jyu, I.-Hung Chen, Tian-Huei Chu, De-Ming Chian, Fu-Kang Wang, Yung-Kuo Lee, and Chou-Yuan Ko, "Accuracy of self-injection locking radar system for vital signs detection during the COVID-19 pandemic at a hospital in taiwan: Measuring vital signs accurately with sil radar for hospital healthcare," Medical Science Monitor, Vol. 29, e939949, 2023.
doi:10.12659/msm.939949        Google Scholar

12. Turppa, Emmi, Juha M. Kortelainen, Oleg Antropov, and Tero Kiuru, "Vital sign monitoring using FMCW radar in various sleeping scenarios," Sensors, Vol. 20, No. 22, 6505, 2020.
doi:10.3390/s20226505        Google Scholar

13. Vignoli, Elia, Pasquale Di Viesti, and Giorgio Matteo Vitetta, "A deterministic method for contactless monitoring of vital signs using multiple FMCW radars in the 24 GHz band," IEEE Access, Vol. 13, 27868-27892, 2025.
doi:10.1109/access.2025.3540316        Google Scholar

14. Seflek, Ibrahim, Yunus Emre Acar, and Ercan Yaldiz, "Small motion detection and non-contact vital signs monitoring with continuous wave doppler radars," Elektronika ir Elektrotechnika, Vol. 26, No. 3, 54-60, 2020.
doi:10.5755/j01.eie.26.3.25810        Google Scholar

15. Cupal, Miroslav and Zbynek Raida, "Slot antennas integrated into 3D knitted fabrics: 5.8 GHz and 24 GHz ISM bands," Sensors, Vol. 22, No. 7, 2707, 2022.
doi:10.3390/s22072707        Google Scholar

16. Khan, Faheem and Sung Ho Cho, "A detailed algorithm for vital sign monitoring of a stationary/non-stationary human through IR-UWB radar," Sensors, Vol. 17, No. 2, 290, 2017.
doi:10.3390/s17020290        Google Scholar

17. Nurhayati, Nurhayati, Fitri Yuli Zulkifli, Ali Hanafiah Rombe, Rohim Aminullah Firdaus, Muhammad Fauzan Edy Purnomo, Minh Thuy Le, and Ahmed J. A. Al-Gburi, "Design and studies of monopole antenna integrated with metamaterial-based CSRR and rectangular spiral shaped for super wide band application," Results in Engineering, Vol. 26, 105459, 2025.
doi:10.1016/j.rineng.2025.105459        Google Scholar

18. Sobrinho, Raimundo Eider Figueredo, Alexandre Manicoba de Oliveira, Antonio Mendes De oliveira Neto, Alexandre Jean Rene Serres, Auzuir R. De Alexandria, Filho, Marcelo B. Perotoni, Nurhayati Nurhayati, and Ingrid C. Nogueira, "Vivaldi antipodal antenna with high gain and reduced side lobe level using slot edge with new neogothic fractal by cantor with application in medical images for tumor detection," INAJEEE (Indonesian Journal of Electrical and Electronics Engineering), Vol. 3, No. 1, 25-31, 2020.
doi:10.26740/inajeee.v3n1.p25-31        Google Scholar

19. Kathuria, Nitin and Boon-Chong Seet, "24 GHz flexible antenna for doppler radar-based human vital signs monitoring," Sensors, Vol. 21, No. 11, 3737, 2021.
doi:10.3390/s21113737        Google Scholar

20. De Cos Gómez, María Elena, Humberto Fernández Álvarez, and Fernando Las-Heras Andrés, "PP-based 24 GHz wearable antenna," Wireless Networks, Vol. 30, No. 2, 867-882, 2024.
doi:10.1007/s11276-023-03533-z        Google Scholar

21. Chen, Pi-Yun, Hsu-Yung Lin, Zi-Heng Zhong, Neng-Sheng Pai, Chien-Ming Li, and Chia-Hung Lin, "Contactless and short‐range vital signs detection with doppler radar millimetre‐wave (76–81 GHz) sensing firmware," Healthcare Technology Letters, Vol. 11, No. 6, 427-436, 2024.
doi:10.1049/htl2.12075        Google Scholar

22. Nurhayati, Nurhayati, Agam N. D. N. Fahmi, Pradini Puspitaningayu, Oce Wiriawan, Brian Raafi'u, Fitri A. Iskandarianto, Ahmed J. A. Al-Gburi, Atul Varshney, and Safpbri Johari, "Wearable wideband textile coplanar vivaldi antenna for medical and IoT application," Progress In Electromagnetics Research C, Vol. 148, 145-156, 2024.
doi:10.2528/pierc24080402        Google Scholar

23. Djouimaa, Awatef and Karima Bencherif, "Design of a compact circular microstrip patch antenna for 5G applications," Engineering, Technology & Applied Science Research, Vol. 14, No. 4, 16020-16024, Aug. 2024.
doi:10.48084/etasr.7961        Google Scholar

24. Karad, Kailash V., Vaibhav S. Hendre, Jaswantsing L. Rajput, Vivek Kadam, Vaibhav E. Narawade, Ravindra Bakale, and Gayatri D. Londhe, "A SAR analysis of hexagonal-shaped UWB antenna for healthcare applications," EURASIP Journal on Wireless Communications and Networking, Vol. 2024, No. 1, 72, 2024.
doi:10.1186/s13638-024-02405-0        Google Scholar

25. Hashim, Fatimah Fawzi, Wan Nor Liza Binti Wan Mahadi, Tarik Bin Abdul Latef, and Mohamadariff Bin Othman, "Fabric-metal barrier for low specific absorption rate and wide-band felt substrate antenna for medical and 5G applications," Electronics, Vol. 12, No. 12, 2754, 2023.
doi:10.3390/electronics12122754        Google Scholar

26. Lu, Shouxun, Kelvin J. Nicholson, Joel Patniotis, John Wang, and Wing Kong Chiu, "The effects of mechanical loading on resonant response of a conformal load-bearing antenna system," Sensors, Vol. 24, No. 19, 6206, 2024.
doi:10.3390/s24196206        Google Scholar

27. Riener, Christian, Thomas Bauernfeind, Samuel Kvasnicka, Klaus Roppert, Herbert Hackl, and Manfred Kaltenbacher, "Numerical investigation of signal launch imperfections for edge mount RF connectors," Electronics, Vol. 11, No. 13, 1990, 2022.
doi:10.3390/electronics11131990        Google Scholar

28. Ali, Mubasher, John C. Batchelor, Irfan Ullah, and Nathan J. Gomes, "Ultra-thin EBG backed flexible antenna for 24 GHz ISM band WBAN," 2022 Antenna Measurement Techniques Association Symposium (AMTA), 1-4, Denver, CO, USA, 2022.
doi:10.23919/amta55213.2022.9954953

29. Berdasco, Alicia Flórez, Maria Elena de Cos Gómez, Jaime Laviada, and Fernando Las-Heras, "AMC-backed twin arrow antenna for wearable electronic travel aid system at 24 GHz," IEEE Antennas and Wireless Propagation Letters, Vol. 23, No. 11, 3337-3341, 2024.
doi:10.1109/lawp.2024.3378012        Google Scholar

30. Aldrigo, M., M. Dragoman, S. Iordanescu, A. Avram, O.-G. Simionescu, C. Parvulescu, H. El Ghannudi, S. Montori, L. Nicchi, S. Xavier, and A. Ziaei, "Tunable 24-GHz antenna arrays based on nanocrystalline graphite," IEEE Access, Vol. 9, 122443-122456, 2021.
doi:10.1109/access.2021.3109420        Google Scholar

31. Sharma, Manoj, Anil Kumar Gautam, Niraj Agrawal, and Neeta Singh, "Design of MIMO planar antenna at 24 GHz band for radar, communication and sensors applications," AEU --- International Journal of Electronics and Communications, Vol. 136, 153747, 2021.
doi:10.1016/j.aeue.2021.153747        Google Scholar

32. Kakaraparty, Karthik and Ifana Mahbub, "Design and performance analysis of a 24 GHz series-fed 1 × 5 antenna array with material deformation for D2D applications," 2023 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (USNC-URSI), 1575-1576, Portland, OR, USA, 2023.
doi:10.1109/usnc-ursi52151.2023.10238054

33. Kim, Sungpeel, Dong Kyoo Kim, Youjin Kim, Jaehoon Choi, and Kyung-Young Jung, "A 24 GHz ISM-band doppler radar antenna with high isolation characteristic for moving target sensing applications," IEEE Antennas and Wireless Propagation Letters, Vol. 18, No. 7, 1532-1536, 2019.
doi:10.1109/lawp.2019.2922008        Google Scholar

34. Yu, Chia-An, Kuo-Sheng Chin, and Roger Lu, "24-GHz wide-beam patch antenna array laterally loaded with parasitic strips," 2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 1-3, Taiyuan, China, 2019.
doi:10.1109/csqrwc.2019.8799203

35. Flórez Berdasco, A., M. E. de Cos Gómez, H. Fernández Álvarez, and F. Las-Heras, "Millimeter wave array-HIS antenna for imaging applications," Applied Physics A, Vol. 129, No. 6, 397, 2023.
doi:10.1007/s00339-023-06676-0        Google Scholar