• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2021, Volume: 14, Issue: 18, Pages: 1477-1487

Original Article

Microstrip patch and Sierpinski fractal antennas: simulations and experimental characterization for vital signs detection with Doppler radar technique

Received Date:09 April 2021, Accepted Date:07 May 2021, Published Date:21 May 2021


Objectives: To fabricate planar models of antennas with resonance frequencies in the ultrahigh frequency band that allow short-range detection of respiration and heartbeat by a simple continuous wave Doppler radar system. Methods: Models of antennas were created in CST Studio software and the main parameters were computed. Then, antennas were fabricated at a PCB prototyping machine and were experimentally characterized in an anechoic chamber. Total efficiency and radiation patterns indicated the best working frequencies of 2.12 GHz and 8.82 GHz respectively, to test the human vital signs detection with a continuous-wave Doppler radar technique in direct visibility conditions. Findings: The patch antenna at 2.12 GHz had a maximum gain of 3.15 dBi and total efficiency of 43% while the Sierpinski antenna at 8.82 GHz had a maximum gain of 5.5 dBi and total efficiency of 65%. At incident power densities on the human subject’s chest of 4.5 x 10-4 mW/m2 and of 2.6 x 10-2 mW/m2 respectively, the Doppler radar system based on these antennas offered precise responses. Practically, it was possible to extract both the heartbeat rate and the respiration rate, by simply applying the classical FFT algorithm on a time-series phase data of the transmission coefficient recorded during 30 seconds, when the set-up was composed of just the antennas and a vector network analyzer. Novelty: Increased detection accuracy was obtained due to careful characterization of the antennas parameters with no need of special processing algorithms.

Keywords: Sierpinski Antenna; Patch Antenna; CW Doppler Radar; Respiration Rate; Heartbeat Rate


  1. Bankey V, Kumar NA. Design and performance issues of Microstrip antennas. International Journal of Scientific and Engineering Research. 2015;6(3):1572–1580. Available from: https://dx.doi.org/10.14299/ijser.2015.03.008
  2. Liu Y, Si LM, Wei M, Yan P, Yang P, Lu H, et al. Some recent developments of microstrip antenna. International Journal of Antennas and Propagation. 2012;(428284 ). Available from: https://doi.org/10.1155/2012/428284
  3. Minhas S, Khosla D, , . Compact Size and Slotted Patch Antenna for WiMAX and WLAN. Indian Journal of Science and Technology. 2017;10(16):1–5. Available from: https://dx.doi.org/10.17485/ijst/2017/v10i16/102762
  4. Singh A, Bera R, Maji B, Gurung R. Microstrip Patch Antenna towards Future of Communication. Indian Journal of Science and Technology. 2019;12(3):1–5. Available from: 10.17485/ijst/2019/v12i3/140904
  5. Anguera J, Andújar A, Jayasinghe J, Chakravarthy VVSSS, Chowdary PSR, Pijoan JL, et al. Fractal Antennas: An Historical Perspective. Fractal and Fractional. 2020;4(1):3. Available from: https://dx.doi.org/10.3390/fractalfract4010003
  6. Sultan QH, Sabaawi AMA. DESIGN AND IMPLEMENTATION OF IMPROVED FRACTAL LOOP ANTENNAS FOR PASSIVE UHF RFID TAGS BASED ON EXPANDING THE ENCLOSED AREA. Progress In Electromagnetics Research C. 2021;111:135–145. Available from: https://dx.doi.org/10.2528/pierc21012206
  7. Salama AMA, Quboa KM. Fractal dipoles as meander line antennas for passive UHF RFID tags. 5th International Multi-Conference on Systems, Signals and Devices. 2008;p. 1–6. Available from: 10.1109/SSD.2008.4632843
  8. Gupta S, Kshirsagar P, Mukherjee B. Sierpinski fractal inspired inverted pyramidal DRA for wide band applications. Electromagnetics. 2018;38(2):103–112. Available from: https://dx.doi.org/10.1080/02726343.2018.1436738
  9. Jayarenjini N, Unni C. MERR Inspired CPW Fed SSGF Antenna for Multiband Operations. Progress In Electromagnetics Research C. 2019;91:197–211. Available from: https://dx.doi.org/10.2528/pierc19020202
  10. Akhtar N, Bhomia Y, Bhardwaj A, , , . Design and Simulation of Sierpinski Carpet Antenna utilizing Two Feeding Method. Indian Journal of Science and Technology. 2017;10(35):1–7. Available from: https://dx.doi.org/10.17485/ijst/2017/v10i35/118957
  11. Gupta M, Mathur V. SierpinskiArray with Swastik Electromagnetic Bandgap for Ku-Band Applications. Indian Journal of Science and Technology. 2016;9(32):1–7. Available from: https://dx.doi.org/10.17485/ijst/2016/v9i32/93833
  12. Vatamanu D, Miclăuş S. UHF Fractal Antennas: Solutions for Radio Links Using Matlab Simulations. International conference KNOWLEDGE-BASED ORGANIZATION. 2020;26(3):179–184. Available from: https://dx.doi.org/10.2478/kbo-2020-0135
  13. Vatamanu D, Miclaus S. An analysis of the Influence of the Dielectric Substrate Parameters on the Performances of Koch and Minkowski Single-Iteration Fractal Antennas. European Journal of Advances in Engineering and Technology. 2020;8(7):1–8.
  14. El-Samad S, Obeid D, Zaharia G, Sadek S. Ghais El Zein. Measurements of Cardiac and Cardiopulmonary Activities Using Contactless Doppler Radar. International Conference on advances in Biomedical Engineering. 2015;p. 193–196. Available from: 10.1109/ICABME.2015.7323285
  15. Wang Y, Liu Q, Fathy AE. CW and Pulse–Doppler Radar Processing Based on FPGA for Human Sensing Applications. IEEE Transactions on Geoscience and Remote Sensing. 2012;51(5):1–11. Available from: https://dx.doi.org/10.1109/tgrs.2012.2217975
  16. Petrovic VL, Jankovic MM, Lupsic AV, Mihajlovic VR, Popovic-Bozovic JS. High-Accuracy Real-Time Monitoring of Heart Rate Variability Using 24 GHz Continuous-Wave Doppler Radar. IEEE Access. 2019;7:74721–74733. Available from: https://dx.doi.org/10.1109/access.2019.2921240
  17. Paleček J, Vestenický M, Vestenický P, Spalek J. Frequency Dependence Examination of PCB Material FR4 Relative Permittivity. Elsevier BV. 2013. doi: 10.3182/20130925-3-cz-3023.00020 Available from: https://dx.doi.org/10.3182/20130925-3-cz-3023.00020
  18. ANSI/IEEE Std 149-1979. IEEE Standard Test Procedures for Antennas. 1979. Available from: 10.1109/IEEESTD.1979.120310
  19. Mukherjee B, Patel P, Mukherjee J. Hemispherical Dielectric Resonator Antenna Based on Apollonian Gasket of Circles—A Fractal Approach. IEEE Transactions on Antennas and Propagation. 2014;62(1):40–47. Available from: https://dx.doi.org/10.1109/tap.2013.2287011
  20. Gupta S, Kshirsagar P, Mukherjee B. Sierpinski fractal inspired inverted pyramidal DRA for wide band applications. Electromagnetics. 2018;38(2):103–112. Available from: https://dx.doi.org/10.1080/02726343.2018.1436738
  21. García-García Q. Radiated cross-polar levels and mutual coupling in patch radiators. International Journal of RF and Microwave Computer-Aided Engineering. 2000;10(6):342–352. Available from: 10.1002/1099-047X(200011)10:6<342::AID-MMCE3>3.0.CO;2-0
  22. Tariq A. Vital Signs Monitoring using Doppler Radar and On-Body Antennas. University of Birmingham thesis
  23. Llamas-Garro I, Melo MTD, Kim JM. Frequency Measurement Technology. (pp. 1-222) 2018.


© 2021 Vatamanu et al.This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee)


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