volume | PIER Journals

Abstract

The use of conformal antennas in a MIMO link scenario is investigated. Conformal slot antennas are considered both in the transmitter and the receiver. First, a new modified correlation coefficient is derived that goes beyond the Clarke coefficient and takes into account the element radiation pattern. Secondly, a hybrid formulation that accounts for the impact of the mutual coupling and the pattern dependent correlation on the capacity is presented. The mutual coupling for slots placed circumferentially on a paraboloid substrate is derived using a rigorous approach based on Uniform Theory of Diffraction (UTD). The capacity is evaluated for the case of Rayleigh fading channel considering the new pattern dependent correlation coefficient and the conformal antenna mutual coupling. The planar case is included as a limiting case. It is shown that for conformal antennas on a paraboloid the capacity degradation compared to the planar case is up to 0.5 bps/Hz due to coupling and correlation.

1. Gesbert, D., M. Shafi, D.-S. Shiu, et al. "From theory to practice: An overview of space time coded wireless systems," IEEE Journal on Selected Areas in Communications, Vol. 21, 283-302, 2003.
doi:10.1109/JSAC.2003.809458

2. Foschini, G. J. and M. J. Gans, "On limits of wireless communications in a fading environment when using multiple antennas," Wireless Personal Communications, Vol. 6, No. 3, 311-335, Mar. 1998.
doi:10.1023/A:1008889222784

3. Shiu, D. S., J. Foschini, J. Gans, and J. M. Kahn, "Fading correlation and its effect on the capacity of multielement antenna system," IEEE Transactions on Communications, Vol. 48, 502, 2000.
doi:10.1109/26.837052

4. Clerckx, B. and C. Oestges, MIMO Wireless Networks: Channels, Techniques and Standards for Multi-antenna, Multi-user and Multi-cell Systems, Academic Press, 2013.

5. Nyberg, D., P. S. Kildal, A. Gummalla, and J. Carlsson, "Degradation of MIMO capacity due to correlation and efficiency of practical antennas," International Symposium on Antennas and Propagation, Taipei, Taiwan, Oct. 27-30, 2008.

6. Gesbert, D., H. Bolcskei, D. Gore, and A. Paulraj, "MIMO wireless channels: Capacity and performance prediction," IEEE Global Telecommunications Conference (GLOBECOM’00), Vol. 2, 2000.

7. Varzakas, P., "Average channel capacity for rayleigh fading spread spectrum MIMO systems," International Journal of Communication Systems, Vol. 19, No. 10, 1081-1087, Dec. 2006.
doi:10.1002/dac.784

8. Janaswamy, R., "Effect of mutual coupling on the capacity of fixed length linear arrays," IEEE Antenna and Wireless Propagation Letters, Vol. 1, 157-160, 2002.
doi:10.1109/LAWP.2002.807570

9. Chae, S., S. Oh, and S. Park, "Analysis of mutual coupling, correlations, and TARC in WiBro MIMO array antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 6, 122-125, 2007.
doi:10.1109/LAWP.2007.893109

10. Fei, Y., Y. Fan, B. K. Lau, and J. S. Thompson, "Optimal single-port matching impedance for MIMO capacity maximization," IEEE Transactions on Antennas and Propagation, Vol. 56, No. 11, 3566-3575, Nov. 2008.

11. Kalialakis, C., A. Collado, and A. Georgiadis, "Capacity of linear rectangular microstrip antenna arrays," Proceedings of 3rd European Conference on Antennas and Propagation (EuCAP 2009), Berlin, Germany, Mar. 23-27, 2009.

12. Josefsson, L. and P. Persson, Conformal Array Antenna Theory and Design, John Wiley & Sons, 2006.
doi:10.1002/047178012X

13. Adams, J. J., E. B. Duoss, T F. Malkowski, et al. "Conformal printing of electrically small antennas on three-dimensional surfaces," Advanced Materials, Vol. 23, No. 11, 1335-1340, Mar. 18, 2011.
doi:10.1002/adma.201003734

14. Nikolaou, S., G. E. Ponchak, J. Papapolymerou, and M. M. Tentzeris, "Conformal double exponentially tapered slot antenna (DETSA) on LCP for UWB applications," IEEE Transactions on Antennas and Propagation, Vol. 54, No. 6, 1663-1669, 2006.
doi:10.1109/TAP.2006.875915

15. Boeykens, F., L. Vallozzi, and H. Rogier, "Cylindrical bending of deformable textile rectangular patch antennas," International Journal on Antennas and Propagation, Article ID 17020, 11 pages, 2012.

16. Tunc, C., A. E. Irci, O. Bakir, et al. "Investigation of planar and conformal printed arrays for MIMO performance analysis," European Conference on Antennas and Propagation (EuCAP), 1-6, Nov. 6-10, 2006.
doi:10.1109/TAP.2006.877762

17. Craddock, I. J., D. L. Paul, C. M. Tan, et al. "Investigation of array performance for MIMO channel characterisation," URSI EMTheory Symposium, 69-71, 2004.

18. Orlob, C., Q. H. Dao, and B. Geck, "Conformal log-periodic antenna with integrated feeding network for UWB-MIMO applications," 7th German Microwave Conference (GeMiC), 1-4, Mar. 12-14, 2012.

19. Yetisir, E., D. Psychoudakis, and J. L. Volakis, "Small size conformal UWB arrays for MIMO and diversity applications," IEEE Antennas and Propagation Society International Symposium, Jul. 8-14, 2012.

20. Gamage, J. K. H., B. Holter, J. A. Jensen, et al. "A wideband conformal antenna array for cognitive radio/MIMO applications," European Conference on Antennas and Propagation (EUCAP), 725-729, Apr. 11-15, 2011.

21. Clarke, R. H., "A statistical theory of mobile radio reception," Bell Systems Technical Journal, Vol. 47, No. 6, 957-1000, Jul.-Aug. 1968.
doi:10.1002/j.1538-7305.1968.tb00069.x

22. Petrus, P., J. Reed, and T. S. Rappaport, "Geometrical-based statistical macrocell channel model for mobile environments," IEEE Transactions on Communications, Vol. 50, 495-502, 2002.
doi:10.1109/26.990911

23. Kaifas, T. N., T. Samaras, K. Siakavara, and J. N. Sahalos, "A UTD-OM technique to design slot arrays on a perfectly conducting paraboloid," IEEE Transactions on Antennas and Propagation, Vol. 53, No. 5, 1688-1698, May 2005.
doi:10.1109/TAP.2005.846791

24. Janaswamy, R., "Spatial diversity for wireless communication systems," Handbook of Antennas in Wireless Communications, Chap. 19, L. C. Godara, ed., CRC Press, 2002.

25. Lipschutz, M. M., Differential Geometry, McGraw-Hill, New York, 1995.

26. Pathak, P. and N. Wang, "Ray analysis of mutual coupling between antennas on a convex surface," IEEE Trans. Antennas Propagat., Vol. 29, No. 6, 911-922, 1981.
doi:10.1109/TAP.1981.1142682

27. Pathak, P., N. Wang, W. D. Burnside, and R. Kouyoumjian, "A uniform GTD solution for the radiation from sources on a convex surface," IEEE Trans. Antennas Propagat., Vol. 29, No. 4, 609-622, 1981.
doi:10.1109/TAP.1981.1142636

28. Wu, K. and B. Ottersten, "Models for MIMO propagation channels - A review," Wirel. Commun. Mob. Comput., 653-666, 2002.

29. Pozar, D., Microwave Engineering, Addison-Wesley, 1993.

30. Kalialakis, C., D. Anagnostou, and M. Chryssomallis, "Mutual coupling effects on the MIMO capacity using dual band Wi-Fi double-T printed antennas," 2015 IEEE AP-S Symposium on Antennas and Propagation, Vancoover, Canada, Jul. 2015.

31. Von Winckel, G., "Legendre-Gauss quadrature weights and nodes,", authored 25/2/2004, Available at http://www.mathworks.com/matlabcentral/fileexchange/4540-legendre-gauss-quadratureweights-and-nodes/content/lgwt.m.

32. Kaifas, T. N., "Study of systems of conformal arrays,", PhD. Dissertation (in Greek), Dept. of Physics, Aristotle University of Thessaloniki, Greece, 2003.

Dr. Christos Kalialakis

Dr. Theodoros Kaifas

Dr. Apostolos Georgiadis