volume | PIER Journals

Abstract

This work introduces a novel compact 4-element MIMO antenna in the form of a q for use in the X-band. The proposed antenna has a footprint of 25 × 25 mm² and can be easily produced using a FR-4 epoxy substrate. The antenna consists of a 50-ohm microstrip line connected to ground and four q-shaped radiators. The antenna's impedance matching characteristics were analysed by performing a parametric study on its several parameters. The antenna has excellent impedance matching capabilities and operates between 7.2 GHz and 12.6 GHz. By utilising the connected ground technique and placing radiating elements in an orthogonal orientation, we can achieve isolation of greater than 15 dB. The measured and simulated results demonstrate the antenna's high peak gain of > 4 dBi and high radiation efficiency of > 90%, as well as its good impedance bandwidth (S₁₁ ≤ 10 dB) and isolation (S₂₁/S₃₁/S₄₁ of ≥ 15 dB). The presented antenna is a good option for X-band applications because its envelope correlation coefficient (ECC) is less than 0.00001, total active reflection coefficient (TARC) less than -10 dB, channel capacity loss (CCL) less than 0.03 bits/sec/Hz, and mean effective gain (MEG) less than -3 dB.

1. Soltani, S. and R. D. Murch, "A compact planar printed MIMO antenna design," IEEE Trans. Antennas Propag., Vol. 63, 1140-1149, 2015.
doi:10.1109/TAP.2015.2389242

2. Addepalli, T., J. B. Kamili, K. K. Bandi, A. Nella, and M. Sharma, "Lotus flower-shaped 4/8-element MIMO antenna for 5G n77 and n78 band applications," Journal of Electromagnetic Waves and Applications, Vol. 36, No. 10, 1404-1422, 2022.
doi:10.1080/09205071.2022.2028683

3. Nirdosh, A. Kakkar, S. Sah, "A two-element wideband MIMO antenna for X band, Ku-band, K-band applications," 2018 5th International Conference on Signal Processing and Integrated Networks (SPIN), Noida, India, Feb. 22-23, 2018.

4. Pouyanfar, N., C. Ghobadi, J. Nourinia, K. Pedram, and M. Majidzadeh, "A compact multiband MIMO antenna with high isolation for C and X bands using defected ground structure," Radioengineering, Vol. 27, No. 3, 686-693, 2018.
doi:10.13164/re.2018.0686

5. Rao, J. C. and V. Nandanavanam, "Trident-shape strip loaded dual band-notched UWB MIMO antenna for portable device applications," AEU-International Journal of Electronics and Communications, Vol. 83, 11-21, 2018.

6. Rao, J. C. and V. Nandanavanam, "A very compact MIMO antenna with triple band-notch function for portable UWB systems," Progress In Electromagnetics Research C, Vol. 82, 13-27, 2018.

7. Addepalli, T. and V. R. Anitha, "Parametric analysis of compact UWB-MIMO antenna with improved isolation using parasitic reflectors and protruded ground strips," Wireless Personal Communications, Vol. 123, No. 3, 2209-2225, 2022.
doi:10.1007/s11277-021-09235-z

8. Addepalli, T. and V. R. Anitha, "A very compact and closely spaced circular shaped UWB MIMO antenna with improved isolation," AEU-International Journal of Electronics and Communications, Vol. 114, 153016, 2020.

9. Dkiouak, A., A. Zakriti, M. El Ouahabi, N. A. Touhami, and A. Mchbal, "Design of a four-element MIMO antenna with low mutual coupling in a small size for satellite applications," Progress In Electromagnetics Research M, Vol. 85, 95-104, 2019.
doi:10.2528/PIERM19071202

10. Sarkar, D. and K. V. Srivastava, "A compact four-element MIMO/diversity antenna with enhanced bandwidth," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 2469-2472, 2017.
doi:10.1109/LAWP.2017.2724439

11. Sghaier, N. and L. Latrach, "Design and analysis of wideband MIMO antenna arrays for 5G smartphone application," International Journal of Microwave and Wireless Technologies, Vol. 14, No. 4, 511-523, 2022.
doi:10.1017/S1759078721000659

12. Kulkarni, J., A. Desai, and C. Y. D. Sim, "Wideband four-port MIMO antenna array with high isolation for future wireless systems," AEU-International Journal of Electronics and Communications, Vol. 128, 153507, 2021.

13. Eslami, A., J. Nourinia, C. Ghobadi, and M. Shokri, "Four-element MIMO antenna for X-band applications," International Journal of Microwave and Wireless Technologies, Vol. 13, No. 8, 859-866, 2021, doi: 10.1017/S1759078720001440.
doi:10.1017/S1759078720001440

14. Nirdosh, C. M. Tan, and M. R. Tripathy, "A miniaturized T-shaped MIMO antenna for X-band and Ku-band applications with enhanced radiation efficiency," 2018 27th Wireless and Optical Communication Conference (WOCC), Hualien, Taiwan, Apr. 30-May 1, 2018.

15. Addepalli, T., T. Vidyavathi, K. Neelima, M. Sharma, and D. Kumar, "Asymmetrical fed Calendula flower-shaped four-port 5G-NR band (n77, n78, and n79) MIMO antenna with high diversity performance," International Journal of Microwave and Wireless Technologies, 1-15, 2022.
doi:10.1017/S1759078722000800

16. Vaughan, R. G. and J. B. Andersen, "Antenna diversity in mobile communications," IEEE Transactions on Vehicular Technology, Vol. 36, No. 4, 149-172, 1987.
doi:10.1109/T-VT.1987.24115

17. Addepalli, T., K. J. Babu, A. Beno, B. M. K. Potti, D. T. Sundari, and V. K. R. Devana, "Characteristic mode analysis of two port semi-circular arc-shaped multiple-input-multiple-output antenna with high isolation for 5G sub-6 GHz and wireless local area network applications," International Journal of Communication Systems, Vol. 35, No. 14, e5257, 2022.
doi:10.1002/dac.5257

18. Fritz-Andrade, E., H. Jardon-Aguilar, and J. A. Tirado-Mendez, "The correct application of total active reflection coefficient to evaluate MIMO antenna systems and its generalization to N ports," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 30, No. 4, e22113, 2020.
doi:10.1002/mmce.22113

19. Eslami, A., J. Nourinia, C. Ghobadi, and M. Shokri, "Four-element MIMO antenna for X-band applications," International Journal of Microwave and Wireless Technologies, Vol. 13, No. 8, 859-866, 2021.
doi:10.1017/S1759078720001440

20. Addepalli, T. and V. R. Anitha, "Compact two-port MIMO antenna with high isolation using parasitic reflectors for UWB, X and Ku band applications," Progress In Electromagnetics Research C, Vol. 102, 63-77, 2020.
doi:10.2528/PIERC20030402

21. Glazunov, A. A., A. F. Molisch, and F. Tufvesson, "Mean effective gain of antennas in a wireless channel," IET Microwaves, Antennas & Propagation, Vol. 3, No. 2, 214-227, 2009.
doi:10.1049/iet-map:20080041

22. Addepalli, T., J. B. Kamili, D. V. Vardhan, K. K. Bandi, R. Manda, B. R. Perli, and V. Satyanarayana, "Design and experimental analysis of dual-port antenna with high isolation for 5G sub 6 GHz: n77/n78/n79 and WiFi-5 bands applications," IETE Journal of Research, 1-10, 2023.
doi:10.1080/03772063.2023.2167740

Dr. Tathababu Addepalli

Mr. Jetti Chandrasekhar Rao

Dr. Penchala Reddy Sura

Dr. Boddapalli Venkata Ramana Ramana

Dr. Vella Satyanarayana