volume | PIER Journals

Abstract

This paper presents a compact four-port conformal multiple-input multiple-output (MIMO) antenna designed on a 0.1-mm-thick transparent flexible polyimide substrate for wideband X-band wireless applications. Each antenna element is composed of an annular ring radiator and an asymmetric coplanar ground to achieve low mutual coupling and high diversity performance. The proposed MIMO antenna covers an impedance bandwidth of 7.9-14 GHz, with isolation greater than 20 dB and a maximum reflection coefficient of 32.5 dB at 10.5 GHz. The experimental results are in good agreement with the simulated results in terms of reflection, transmission, and radiation characteristics. The measured gain ranges from 4.5 to 6 dBi, with stable radiation patterns across the operating band. The MIMO performance metrics, including the envelope correlation coefficient (ECC = 0.002), diversity gain (≈10 dB), channel capacity loss (<0.3 bits/s/Hz), and total active reflection coefficient (TARC), confirm the suitability of the design for robust high-data-rate communication. Furthermore, the antenna maintains stable operation under various bending configurations, ensuring its potential for X-band conformal and wearable applications.

1. Yan, Sen and Guy A. E. Vandenbosch, "Radiation pattern-reconfigurable wearable antenna based on metamaterial structure," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 1715-1718, 2016.
doi:10.1109/lawp.2016.2528299 Google Scholar

2. Gao, Guo-Ping, Bin Hu, Xiao-Long Tian, Qing-Lin Zhao, and Bing-Tao Zhang, "Experimental study of a wearable aperture-coupled patch antenna for wireless body area network," Microwave and Optical Technology Letters, Vol. 59, No. 4, 761-766, 2017.
doi:10.1002/mop.30408 Google Scholar

3. Van Torre, Patrick, Luigi Vallozzi, Carla Hertleer, Hendrik Rogier, Marc Moeneclaey, and Jo Verhaevert, "Indoor off-body wireless MIMO communication with dual polarized textile antennas," IEEE Transactions on Antennas and Propagation, Vol. 59, No. 2, 631-642, 2011.
doi:10.1109/tap.2010.2096389 Google Scholar

4. Yan, Sen, Ping Jack Soh, and Guy A. E. Vandenbosch, "Dual-band textile MIMO antenna based on substrate-integrated waveguide (SIW) technology," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 11, 4640-4647, 2015.
doi:10.1109/tap.2015.2477094 Google Scholar

5. Xu, Decheng, Xiaojian Tian, Xiaohui Guo, Wenlong Jiang, Wei Liu, and Scott Xing, "Design and research of flexible wearable textile antenna based on GNPs/PANI/PDMS composites for 2.45 GHz," Nanoscience and Nanotechnology Letters, Vol. 9, No. 4, 476-480, 2017.
doi:10.1166/nnl.2017.2330 Google Scholar

6. Yamanaka, D. and M. Takahashi, "5.2 GHz band textile antenna for biological information monitoring," IEICE Transactions on Communications, Vol. J101-B, No. 7, 584-591, 2018.
doi:10.14923/transcomj.2017JBP3057 Google Scholar

7. Zhu, Shaozhen and Richard Langley, "Dual-band wearable textile antenna on an EBG substrate," IEEE Transactions on Antennas and Propagation, Vol. 57, No. 4, 926-935, 2009.
doi:10.1109/tap.2009.2014527 Google Scholar

8. Iqbal, Amjad, Abdul Basir, Amor Smida, Nazih Khaddaj Mallat, Issa Elfergani, Jonathan Rodriguez, and Sunghwan Kim, "Electromagnetic bandgap backed millimeter-wave MIMO antenna for wearable applications," IEEE Access, Vol. 7, 111135-111144, 2019.
doi:10.1109/access.2019.2933913 Google Scholar

9. Abbasi, Muhammad Ali Babar, Symeon Simos Nikolaou, Marco A. Antoniades, Marija Nikolić Stevanović, and Photos Vryonides, "Compact EBG-backed planar monopole for BAN wearable applications," IEEE Transactions on Antennas and Propagation, Vol. 65, No. 2, 453-463, 2017.
doi:10.1109/tap.2016.2635588 Google Scholar

10. Raad, Haider R., Ayman I. Abbosh, Hussain M. Al-Rizzo, and Daniel G. Rucker, "Flexible and compact AMC based antenna for telemedicine applications," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 2, 524-531, 2013.
doi:10.1109/tap.2012.2223449 Google Scholar

11. El Atrash, Mohamed, Mahmoud A. Abdalla, and Hadia M. Elhennawy, "A wearable dual-band low profile high gain low SAR antenna AMC-backed for WBAN applications," IEEE Transactions on Antennas and Propagation, Vol. 67, No. 10, 6378-6388, 2019.
doi:10.1109/tap.2019.2923058 Google Scholar

12. Jiang, Zhi Hao, Donovan E. Brocker, Peter E. Sieber, and Douglas H. Werner, "A compact, low-profile metasurface-enabled antenna for wearable medical body-area network devices," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 8, 4021-4030, 2014.
doi:10.1109/tap.2014.2327650 Google Scholar

13. Chen, Yen-Sheng and Ting-Yu Ku, "A low-profile wearable antenna using a miniature high impedance surface for smartwatch applications," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 1144-1147, 2016.
doi:10.1109/lawp.2015.2496366 Google Scholar

14. Joubert, Johan, J. C. Vardaxoglou, William G. Whittow, and Johann W. Odendaal, "CPW-fed cavity-backed slot radiator loaded with an AMC reflector," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 2, 735-742, 2012.
doi:10.1109/tap.2011.2173152 Google Scholar

15. Elfergani, Issa, Amjad Iqbal, Chemseddine Zebiri, Abdul Basir, Jonathan Rodriguez, Maryam Sajedin, Artur de Oliveira Pereira, Widad Mshwat, Raed Abd-Alhameed, and Sadiq Ullah, "Low-profile and closely spaced four-element MIMO antenna for wireless body area networks," Electronics, Vol. 9, No. 2, 258, 2020.
doi:10.3390/electronics9020258 Google Scholar

16. Ling, XueMing and RongLin Li, "A novel dual-band MIMO antenna array with low mutual coupling for portable wireless devices," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 1039-1042, 2011.
doi:10.1109/lawp.2011.2169035 Google Scholar

17. Gupta, Anupma, Ankush Kansal, and Paras Chawla, "Design of a wearable MIMO antenna deployed with an inverted U-shaped ground stub for diversity performance enhancement," International Journal of Microwave and Wireless Technologies, Vol. 13, No. 1, 76-86, 2021.
doi:10.1017/s1759078720000471 Google Scholar

18. Shamsuri Agus, Amira Nur Suraya, Thennarasan Sabapathy, Muzammil Jusoh, Mahmoud A. Abdelghany, Kabir Hossain, Surentiran Padmanathan, Samir Salem Al-Bawri, and Ping Jack Soh, "Combined RIS and EBG surfaces inspired meta-wearable textile MIMO antenna using viscose-wool felt," Polymers, Vol. 14, No. 10, 1989, 2022.
doi:10.3390/polym14101989 Google Scholar

19. Lu, Xuyang, Suresh Venkatesh, Hooman Saeidi, and Kaushik Sengupta, "Integrated intelligent electromagnetic radiator design for future THz communication: A review," Chinese Journal of Electronics, Vol. 31, No. 3, 499-515, 2022.
doi:10.1049/cje.2021.00.324 Google Scholar

20. Kumar Biswas, Ashim and Ujjal Chakraborty, "Compact wearable MIMO antenna with improved port isolation for ultra‐wideband applications," IET Microwaves, Antennas & Propagation, Vol. 13, No. 4, 498-504, 2019.
doi:10.1049/iet-map.2018.5599 Google Scholar

21. Wen, Dingliang, Yang Hao, Max O. Munoz, Hanyang Wang, and Hai Zhou, "A compact and low-profile MIMO antenna using a miniature circular high-impedance surface for wearable applications," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 1, 96-104, 2018.
doi:10.1109/tap.2017.2773465 Google Scholar

22. Biswas, Ashim Kumar and Ujjal Chakraborty, "A compact wide band textile MIMO antenna with very low mutual coupling for wearable applications," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 29, No. 8, e21769, 2019.
doi:10.1002/mmce.21769 Google Scholar

23. Roy, Sourav, Soumendu Ghosh, Soumya Sundar Pattanayak, and Ujjal Chakarborty, "Dual‐polarized textile‐based two/four element MIMO antenna with improved isolation for dual wideband application," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 30, No. 9, e22292, 2020.
doi:10.1002/mmce.22292 Google Scholar

24. Biswas, Ashim Kumar and Ujjal Chakraborty, "Reconfigurable wide band wearable multiple input multiple output antenna with hanging resonator," Microwave and Optical Technology Letters, Vol. 62, No. 3, 1352-1359, 2020.
doi:10.1002/mop.32151 Google Scholar

25. Liu, Feng, Jiayin Guo, Luyu Zhao, Guan-Long Huang, Yingsong Li, and Yingzeng Yin, "Dual-band metasurface-based decoupling method for two closely packed dual-band antennas," IEEE Transactions on Antennas and Propagation, Vol. 68, No. 1, 552-557, 2020.
doi:10.1109/tap.2019.2940316 Google Scholar

26. Liu, Feng, Jiayin Guo, Luyu Zhao, Guan-Long Huang, Yingsong Li, and Yingzeng Yin, "Ceramic superstrate-based decoupling method for two closely packed antennas with cross-polarization suppression," IEEE Transactions on Antennas and Propagation, Vol. 69, No. 3, 1751-1756, 2021.
doi:10.1109/tap.2020.3016388 Google Scholar

27. Li, H., S. Sun, B. Wang, and F. Wu, "Design of compact single-layer textile MIMO antenna for wearable applications," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 6, 3136-3141, 2018.
doi:10.1109/tap.2018.2811844 Google Scholar

28. Iqbal, Amjad, Amor Smida, Abdullah J. Alazemi, Mohamed I. Waly, Nazih Khaddaj Mallat, and Sunghwan Kim, "Wideband circularly polarized MIMO antenna for high data wearable biotelemetric devices," IEEE Access, Vol. 8, 17935-17944, 2020.
doi:10.1109/access.2020.2967397 Google Scholar

29. Li, Wentao, Yongqiang Hei, Peter Mack Grubb, Xiaowei Shi, and Ray T. Chen, "Compact inkjet-printed flexible MIMO antenna for UWB applications," IEEE Access, Vol. 6, 50290-50298, 2018.
doi:10.1109/access.2018.2868707 Google Scholar

30. Bell, A. J., Roberto Fossi, and Caterina Petrucci, "Calculations of dielectric properties from the superparaelectric model of relaxors," Journal of Physics: Condensed Matter, Vol. 5, No. 46, 8773, 1993.
doi:10.1088/0953-8984/5/46/015 Google Scholar

31. Kulkarni, Jayshri, Chow-Yen-Desmond Sim, Ajay K. Poddar, Ulrich L. Rohde, and Abdullah G. Alharbi, "A compact circularly polarized rotated L-shaped antenna with J-shaped defected ground strucutre for WLAN and V2X applications," Progress In Electromagnetics Research Letters, Vol. 102, 135-143, 2022.
doi:10.2528/pierl22010305 Google Scholar

32. Kulkarni, Jayshri, Chow-Yen-Desmond Sim, Brian Garner, and Yang Li, "A dual-CP quad-port MIMO antenna with reduced mutual coupling for X-band application," IEEE Antennas and Wireless Propagation Letters, Vol. 22, No. 9, 2085-2089, 2023.
doi:10.1109/lawp.2023.3275530 Google Scholar

33. Elwi, Taha A. and Ali M. Al-Saegh, "Further realization of a flexible metamaterial-based antenna on indium nickel oxide polymerized palm fiber substrates for RF energy harvesting," International Journal of Microwave and Wireless Technologies, Vol. 13, No. 1, 67-75, 2021.
doi:10.1017/s1759078720000665 Google Scholar

34. Haque, SK. Moinul and Hashibul Alam, "Miniaturized dual‐band slot antenna design for GPS, amateur radio and WLAN applications," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 30, No. 4, e22125, 2020.
doi:10.1002/mmce.22125 Google Scholar

35. Kulkarni, Jayshri Sharad and Chow-Yen Desmond Sim, "Low-profile, multiband & wideband `C-Shaped' monopole antenna for 5G and WLAN applications," 2020 International Conference on Radar, Antenna, Microwave, Electronics, and Telecommunications (ICRAMET), 366-371, Tangerang, Indonesia, 2020.
doi:10.1109/ICRAMET51080.2020.9298569

36. Kulkarni, Neeta P., Nilesh Bhaskarrao Bahadure, P. D. Patil, and Jayshri S. Kulkarni, "Flexible interconnected 4-port MIMO antenna for sub-6 GHz 5G and X band applications," AEU --- International Journal of Electronics and Communications, Vol. 152, 154243, 2022.
doi:10.1016/j.aeue.2022.154243 Google Scholar

37. Al-Khaylani, Hayder H., Taha A. Elwi, and Abdullahi A. Ibrahim, "A novel miniaturized reconfigurable microstrip antenna based printed metamaterial circuitries for 5G applications," Progress In Electromagnetics Research C, Vol. 120, 1-10, 2022.
doi:10.2528/pierc22021503 Google Scholar

38. Patel, Riki and Trushit K. Upadhyaya, "Compact planar dual band antenna for WLAN application," Progress In Electromagnetics Research Letters, Vol. 70, 89-97, 2017.
doi:10.2528/pierl17062704 Google Scholar

39. Sura, Penchala Reddy and M. Sekhar, "Circularly polarized dual band dual slot antenna for WLAN, Wi-MAX and Wi-Fi applications," IETE Journal of Research, Vol. 69, No. 3, 1550-1555, 2023.
doi:10.1080/03772063.2020.1871423 Google Scholar

40. Ali, M. S. M., S. K. A. Rahim, M. I. Sabran, M. Abedian, A. Eteng, and M. T. Islam, "Dual band miniaturized microstrip slot antenna for WLAN applications," Microwave and Optical Technology Letters, Vol. 58, No. 6, 1358-1362, 2016.
doi:10.1002/mop.29803 Google Scholar

41. Elwi, Taha A., Daniya Amer Jassim, and Hayder Hassan Mohammed, "Novel miniaturized folded UWB microstrip antenna‐based metamaterial for RF energy harvesting," International Journal of Communication Systems, Vol. 33, No. 6, e4305, 2020.
doi:10.1002/dac.4305 Google Scholar

42. Joshi, Rahil, Ezzaty Faridah Nor Mohd Hussin, Ping Jack Soh, Mohd Faizal Jamlos, Herwansyah Lago, Azremi Abdullah Al-Hadi, and Symon K. Podilchak, "Dual-band, dual-sense textile antenna with AMC backing for localization using GPS and WBAN/WLAN," IEEE Access, Vol. 8, 89468-89478, 2020.
doi:10.1109/access.2020.2993371 Google Scholar

43. Bag, Biplab, Priyabrata Biswas, Rahul Mondal, Sushanta Biswas, and Partha Pratim Sarkar, "Dual-band dual-sense circularly polarized U-and L-shaped strip monopole antenna for WiMAX/WLAN applications," Journal of Electromagnetic Waves and Applications, Vol. 33, No. 18, 2434-2448, 2019.
doi:10.1080/09205071.2019.1684387 Google Scholar

44. Gowrish, B. and A. Basu, "Analysis and design of a dual-band stepped impedance PCB monopole antenna," IETE Journal of Education, Vol. 58, No. 1, 29-38, 2017.
doi:10.1080/09747338.2017.1332495 Google Scholar

45. Blanch, S., J. Romeu, and I. Corbella, "Exact representation of antenna system diversity performance from input parameter description," Electronics Letters, Vol. 39, No. 9, 705-707, 2003.
doi:10.1049/el:20030495 Google Scholar

46. Agarwal, Shobit and Umair Raque, "A small-scaled super wideband circular ring fractal antenna with high BDR for SHF applications," Progress In Electromagnetics Research C, Vol. 134, 53-63, 2023.
doi:10.2528/pierc23033110 Google Scholar

47. Talukder, Md. Siam, Md. Mottahir Alam, Mohammad Tariqul Islam, Md. Moniruzzaman, Rezaul Azim, Abdullah G. Alharbi, Asif Irshad Khan, Muhammad Moinuddin, and Md. Samsuzzaman, "Rectangular slot with inner circular ring patch and partial ground plane based broadband monopole low SAR patch antenna for head imaging applications," Chinese Journal of Physics, Vol. 77, 250-268, 2022.
doi:10.1016/j.cjph.2022.03.002 Google Scholar

48. Kumar Saurabh, A., P. Singh Rathore, and M. Kumar Meshram, "Compact wideband four-element MIMO antenna with high isolation," Electronics Letters, Vol. 56, No. 3, 117-119, 2020.
doi:10.1049/el.2019.2871 Google Scholar

49. Jhunjhunwala, Vikash Kumar, Pramod Kumar, Arun P. Parameswaran, Pallavi R. Mane, Om Prakash Kumar, Tanweer Ali, Sameena Pathan, Shweta Vincent, and Praveen Kumar, "A four port flexible UWB MIMO antenna with enhanced isolation for wearable applications," Results in Engineering, Vol. 24, 103147, 2024.
doi:10.1016/j.rineng.2024.103147 Google Scholar

Dr. Velraju Prithivirajan

Dr. Kannan Vishnulakshmi

Dr. Palaniselvan Sundaravadivel

Dr. Muthu Manickam Anbarasu

Dr. Dhanushkodi Siva Sundhara Raja

Dr. Dhandapani Rajeshkumar