Nowadays everyone needs electronic gadgets in compact size, and single device should accomplish all the tasks. A compact MIMO antenna resonating at multi-band of frequencies is proposed in the current research work. The proposed MIMO antenna consists of two elements. The edge to edge separation between the two antennas is λ0/31 and still maintains low mutual coupling levels between the two antennas. The proposed MIMO antenna resonates at 4.75 GHz, 5.89 GHz, 6.74 GHz, 8.25 GHz and 9.82 GHz. The mutual coupling is reduced by -23.78 dB at 4.75 GHz, -25.71 dB at 5.89 GHz, -29 dB at 6.74 GHz, -32.79 dB at 8.25 GHz and -21.5 dB at 9.82 GHz, respectively. The performance of the proposed MIMO system was evaluated in terms of S-parameters, Envelope Correlation Coefficient (ECC), Voltage Standing Wave Ratio (VSWR), and Radiation Pattern. The measured and simulated results are presented.
2. Li, Q., A. P. Feresidis, M. Mavridou, and P. S. Hall, "Miniaturized double-layer EBG structures for broadband mutual coupling reduction between UWB monopoles," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 3, 1168-1171, March 2015.
3. Al-Hasan, M. J., T. A. Denidni, and A. R. Sebak, "Millimeter-wave compact EBG structure for mutual coupling reduction applications," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 2, 823-828, February 2015.
4. Karimian, R., A. Kesavan, M. Nedil, and T. A. Denidni, "Low mutual coupling 60 GHz MIMO antenna system with frequency selective surface wall," IEEE Antennas & Wireless Propagation Letters, Vol. 16, No. 99, 373-376, 2017.
5. Von B. M. Trindade, D., C. M¨uller, M. C. F. De Castro, and F. C. C. De Castro, "Metamaterials applied to ESPAR antenna for mutual coupling reduction," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 430-433, 2015.
6. Li, Z., Z. Du, M. Takahashi, K. Saito, and K. Ito, "Reducing mutual coupling of MIMO antennas with parasitic elements for mobile terminals," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 2, 473-481, February 2012.
7. Farsi, S., H. Aliakbarian, D. Schreurs, B. Nauwelaers, and G. A. E. Vandenbosch, "Mutual coupling reduction between planar antennas by using a simple microstrip U-section," IEEE Antennas and Wireless Propagation Letters, Vol. 11, No. 4, 1501-1503, 2012.
8. Zhang, S. and G. F. Pedersen, "Mutual coupling reduction for UWB MIMO antennas with a wideband neutralization line," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 166-169, 2016.
9. Zhai, G., Z. N. Chen, and X. Qing, "Mutual coupling reduction of a closely spaced four-element MIMO antenna system using discrete mushrooms," IEEE Transactions on Microwave Theory and Techniques, Vol. 64, No. 10, October 2016.
10. Talha, M. Y., K. J. Babu, and R. W. Aldhaheri, "Design of a compact MIMO antenna system with reduced mutual coupling," International Journal of Microwave and Wireless Technologies, Vol. 8, No. 1, 117-124, 2016.
11. Allam, A. M. M. A. and A. M. G. Hemdan, "Novel DGS shape for mutual coupling reduction," GeMiC 2016, Bochum, Germany, March 14-16, 2016.
12. Qi, H., L. Liu, X. Yin, H. Zhao, and W. J. Kulesza, "Mutual coupling suppression between two closely spaced microstrip antennas with an asymmetrical coplanar strip wall," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 2016.
13. Xu, H.-X., S. Tang, G. Wang, T. Cai, W. Huang, Q. He, S. Sun, and L. Zhou, "Multifunctional microstrip array combining a linear polarizer and focusing metasurface," IEEE Transactions on Antennas and Propagation, Vol. 64, No. 8, 3676-3682, 2016.
14. Xu, H.-X., T. Cai, Y.-Q. Zhuang, Q. Peng, G.-M. Wang, and J.-G. Liang, "Dual-mode transmissive metasurface and its applications in multibeam transmitarray," IEEE Transactions on Antennas and Propagation, Vol. 65, No. 4, 1797-1806, 2017.
15. Xu, H.-X., S. Tang, X. Ling, W. Luo, and L. Zhou, "Flexible control of highly-directive emissions based on bifunctional metasurfaces with low polarization cross-talking," Annalen der Physik (Berlin), 1700045, 2017.
16. Xu, H.-X., S. Sun, S. Tang, S. Ma, Q. He, G.-M. Wang, T. Cai, H.-P. Li, and L. Zhou, "Dynamical control on helicity of electromagnetic waves by tunable metasurfaces," Scientific Reports, Vol. 6, 27503, 2016.
17. Xu, H.-X., G.-M. Wang, and M.-Q. Qi, "Hilbert-shaped magnetic waveguided metamaterials for electromagnetic coupling reduction of microstrip antenna array," IEEE Transactions on Magnetics, Vol. 49, No. 4, April 2013.
18. Xu, H.-X., G.-M. Wang, M.-Q. Qi, and H.-Y. Zeng, "Ultra-small single-negative electric metamaterials for electromagnetic coupling reduction of microstrip antenna array," Optics Express, Vol. 20, No. 20, 21970, September 24, 2012.
19. Gupta, R. K., T. Shanmuganantham, and R. Kiruthika, "A staircase hexagonal shaped microstrip patch antenna for multiband applications," International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), 2016.
20. Babu, K. J., R. W. Aldhaheri, M. Y. Talha, and I. S. Alruhaili, "Design of a compact two element MIMO antenna system with improved isolation," Progress In Electromagnetics Research Letters, Vol. 48, 27-32, 2014.
21. Babu, K. J., K. S. Ramakrishna, and L. P. Reddy, "A triband swastika shaped patch antenna with reduced mutual coupling for wireless mimo systems," Journal of Electronics (CHINA), Vol. 28, No. 4/5/6, November 2011.
22. Karimian, R., M. Soleimani, and S. M. Hashemi, "Tri-band four elements MIMO antenna system for WLAN and WiMAX application," Journal of Electromagnetic Waves and Applications, Vol. 26, No. 17-18, 2348-2357, December 2012.
23. Manteghi, M. and Y. Rahmat-Samii, "Novel compact tri-band two-element and four-element MIMO antenna designs," Antennas and Propagation Society International Symposium 2006, IEEE, 2006.
24. Li, Q., A. P. Feresidis, M. Mavridou, and P. S. Hall, "Miniaturized double-layer EBG structures for broadband mutual coupling reduction between UWB monopoles," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 3, 1168-1171, 2015.
25. Mao, C.-X., Q.-X. Chu, Y.-T. Wu, and Y.-H. Qian, "Design and investigation of closely-packed diversity UWB slot-antenna with high isolation," Progress In Electromagnetics Research C, Vol. 41, 13-25, 2013.