In this paper, a 3-port compact MIMO antenna is designed using Characteristics Mode Analysis (CMA). It consists of three antenna elements. Ant-1 is 45˚ tilted, and Ant-2 and Ant-3 has L-bend transitions. Ant-2 is 1/4th, and Ant-3 is 1/2 in size w.r.t. Ant-1. To improve 10-dB impedance bandwidth and isolation > 17 dB, fractal slot is etched at bottom, and deformity in antenna structures has three distinct modes. Ant-1 operates in UWB mode from (4.8-10.6) GHz with 75.32% IBW, and Ant-2 and Ant-3 operate in wide-band mode from (8.1-10.8) GHz with 28.57% IBW and from (7.2-9.8) GHz with 30.58% IBW. CMA is utilized to investigate the anonymous behaviour of antenna, predicts modal significance (MS), characteristics angle (CA) and eigen values (EV). From these parameters bandwidth potential, radiation energy source and Q-factor are estimated. For investigations first six modes are swept in modal navigator, where dominant modes are traced as ideal antenna resonant modes, and unwanted modes are neglected. The antenna gain is (3-7) dBi with ECC < 0.08. The proposed antenna is fabricated and measured for validation. From the outcomes, it is found suitable for UWB, air traffic and defense tracking, meteorological, amateur satellite, maritime vessel traffic controlling, and X-band satellite applications.
2. Marzetta, T. L., "Massive MIMO: An introduction," Bell Labs Technical Journal, Vol. 20, No. 8, 11-22, 2015.
3. Mohammad, S. S., Printed MIMO Antenna Engineering, Artech House, 2014.
4. Jusoh, M., M. F. Bin Jamlos, M. R. Kamarudin, and M. F. Bin Abd Malek, "A MIMO antenna design challenges for UWB application," Progress In Electromagnetics Research B, Vol. 36, 357-371, 2012.
5. Sharawi, M. S., "Printed MIMO antenna systems: Performance metrics, implementations and challenges," Forum for Electromagnetic Research Methods and Application Technologies (FERMAT), Vol. 1, 1-11, 2014.
6. Chiu, C.-Y., J.-B. Yan, and R. D. Murch, "Compact three-port orthogonally polarized MIMO antennas," IEEE Antennas and Wireless Propagation Letters, Vol. 6, 619-622, 2007.
7. Sarrazin, J., Y. Mahe, S. Avrillon, and S. Toutain, "Investigation on cavity/slot antennas for diversity and MIMO systems: The example of a three-port antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 7, 414-417, 2008.
8. Kotb, I. E., R. S. Ghoname, H. H. Ghoz, and H. Kaldass, "Three port MIMO antenna for 4G application," International Journal of Advancements in Research & Technology, Vol. 1, No. 4, 1-3, 2012.
9. Wang, H., L. Liu, Z. Zhang, and Z. Feng, "Wideband tri-port MIMO antenna with compact size and directional radiation pattern," Electronics Letters, Vol. 50, No. 18, 1261-1262, 2014.
10. Wang, H., L. Liu, Z. Zhang, Y. Li, and Z. Feng, "Ultra-compact three-port MIMO antenna with high isolation and directional radiation patterns," IEEE Antennas and Wireless Propagation Letters, Vol. 13, 1545-1548, 2014.
11. Bahramzy, P., S. Svendsen, and G. F. Pedersen, "Isolation between three antennas at 700 MHz: For handheld terminals," IET Microwaves, Antennas and Propagation, Vol. 9, No. 3, 237-242, 2014.
12. Sharma, Y., D. Sarkar, K. Saurav, and K. V. Srivastava, "Three-element MIMO antenna system with pattern and polarization diversity for WLAN applications," IEEE Antennas and Wireless Propagation Letters, Vol. 16, , 1163-1166, 2016.
13. Abdalrazik, A., A. S. Abd El-Hameed, and A. B. Abdel-Rahman, "A three-port MIMO dielectric resonator antenna using decoupled modes," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 3104-3107, 2017.
14. Deng, J.-Y., J.-Y. Li, and L.-X. Guo, "Decoupling of a three-port MIMO antenna with different impedances using reactively loaded dummy elements," IEEE Antennas and Wireless Propagation Letters, Vol. 17, No. 3, 430-433, 2018.
15. Saurav, K., N. K. Mallat, and Y. M. M. Antar, "A three-port polarization and pattern diversity ring antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 17, No. 7, 1324-1328, 2018.
16. Swapna, S. P., G. S. Karthikeya, S. K. Koul, and A. Basu, "Three-port pattern diversity antenna module for 5.2 GHz ceiling-mounted WLAN access points," Progress In Electromagnetics Research C, Vol. 98, 57-67, 2020.
17. Chen, W.-S. and R.-D. Lin, "Three-port MIMO antennas for laptop computers using an isolation element as a radiator," International Journal of RF and Microwave Computer-Aided Engineering, 2020.
18. Garbacz, R. J., "Modal expansions for resonance scattering phenomena," Proceedings of the IEEE, Vol. 53, No. 8, 856-864, 1965.
19. Harrington, R. and J. Mautz, "Theory of characteristic modes for conducting bodies," IEEE Transactions on Antennas and Propagation, Vol. 19, No. 5, 622-628, 1971.
20. Mohanty, A. and B. R. Behera, "Investigation of 2-port UWB MIMO diversity antenna design using characteristics mode analysis," AEU --- International Journal of Electronics and Communications, Vol. 124, No. 5, 153361, 2020.
21. Zhao, X., S. P. Yeo, and L. C. Ong, "Planar UWB MIMO antenna with pattern diversity and isolation improvement for mobile platform based on the theory of characteristic modes," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 1, 420-425, 2017.
22. Perli, B. R. and A. M. Rao, "Characteristic mode analysis of wideband microstrip antenna," Progress In Electromagnetics Research C, Vol. 97, 201-212, 2019.
23. Elshirkasi, A. M., A. Abdullah Al-Hadi, M. F. Mansor, R. Khan, and P. J. Soh, "Envelope correlation coefficient of a two-port MIMO terminal antenna under uniform and Gaussian angular power spectrum with user’s hand effect," Progress In Electromagnetics Research C, Vol. 92, 123-136, 2019.
24. Kildal, P.-S. and K. Rosengren, "Correlation and capacity of MIMO systems and mutual coupling, radiation efficiency, and diversity gain of their antennas: Simulations and measurements in a reverberation chamber," IEEE Communications Magazine, Vol. 42, No. 12, 104-112, 2004.
25. Anguera, J., J.-P. Daniel, C. Borja, J. Mumbru, C. Puente, T. Leduc, N. Laeveren, and P. van Roy, "Metallized foams for fractal-shaped microstrip antennas," IEEE Antennas and Propagation Magazine, Vol. 50, No. 6, 20-37, 2008.
26. Anguera, J., C. Puente, C. Borja, and J. Soler, "Fractal shaped antennas: A review," Wiley Encyclopedia of RF and Microwave Engineering, Vol. 2, 1620-1635, edited by K. Chang, 2005.
27. Mohanty, A. and S. Sahu, "High isolation two-port compact MIMO fractal antenna with Wi-Max and X-band suppression characteristics," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 30, No. 1, e22021, 2020.
28. Valagiannopoulos, C., "On measuring the permittivity tensor of an anisotropic material from the transmission coefficients," Progress In Electromagnetics Research B, Vol. 9, 105-116, 2008.
29. Zhou, T., T. Hu, and Z. Ge, "Dispersive rayleigh wave attenuation using inverse-dispersion method," ASEG Extended Abstracts, 1-4, 2010.
30. Tagay, Z. and C. Valagiannopoulos, "Highly selective transmission and absorption from metasurfaces of periodically corrugated cylindrical particles," Phys. Rev. B, Vol. 98, No. 11, 115306, 10 Pages, 2018.
31. Siddiqui, O. F. and A. S. Mohra, "Microwave dielectric sensing in hyperbolically dispersive media," IEEE Sensors Letters, Vol. 1, No. 6, 1-4, 2017.
32. Valagiannopoulos, C. A. and S. A. Tretyakov, "Symmetric absorbers realized as gratings of PEC cylinders covered by ordinary dielectrics," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 10, 5089-5098, 2014.
33. Alitalo, P., C. A. Valagiannopoulos, and S. A. Tretyakov, "Simple cloak for antenna blockage reduction," 2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 669-672, Spokane, WA, USA, 2011.
34. Chen, L., X. Ren, Y.-Z. Yin, and Z. Wang, "Broadband CPW-fed circularly polarized antenna with an irregular slot for 2.45 GHz RFID reader," Progress In Electromagnetics Research Letters, Vol. 41, 77-86, 2013.
35. Valagiannopoulos, C., "Single-series solution to the radiation of loop antenna in the presence of a conducting sphere," Progress In Electromagnetics Research, Vol. 71, 277-294, 2007.