In magnetic induction communication systems, channel capacity is often a major bottleneck that limits the system performance. This paper proposes a method to increase the channel capacity in such systems by means of an antenna array. A central challenge in the design of magnetic antenna arrays is to achieve low intra-array coupling along with high gain. These two properties are essential for increasing the channel capacity in comparison to single antenna communication systems of comparable volume. The method proposed in this paper utilizes circular loop antennas to reduce the intra-array coupling using magnetic flux cancellation. The mathematic approach employed in this paper considers each coil as a system of coupled inductors, where each inductor is a single turn loop, and the total coil self and mutual inductances are computed by summing the appropriate single turn loop inductances. Volume efficient coil topologies are identified, and an optimization method is proposed to minimize the intra-array coupling, subject to a required inductance. The proposed method allows to design volume efficient, up to 3×3, array, or pyramidal shaped 4×4 arrays. The results are verified experimentally using the multiple-frequency communication mode.
2. Sun, Z., P. Wang, M. C. Vuran, M. A. Al-Rodhaan, A. M. Al-Dhelaan, and I. F. Akyildiz, "Misepipe: Magnetic induction-based wireless sensor networks for underground pipeline monitoring," Ad Hoc Networks Journal, Vol. 9, No. 3, 218-227, Elsevier, 2011.
3. Tan, X. and Z. Sun, "An optimal leakage detection strategy for underground pipelines using magnetic induction-based sensor networks," International Conference on Wireless Algorithms, Systems, and Applications, 414-425, Springer, 2013.
4. Tariq, A. K., A. T. Ziyad, and A. O. Abdullah, "Wireless sensor networks for leakage detection in underground pipelines: A survey," Procedia Computer Science, Vol. 21, 491-498, 2013.
5. Sun, Z. and B. Zhu, "Channel and energy analysis on magnetic induction-based wireless sensor networks in oil reservoirs," IEEE International Conference on Communications (ICC), 1748-1752, 2013.
6. Agbinya, J. I., Principles of Inductive Near Field Communications for Internet of Things, River Publishers, Denmark, 2011, ISBN: 978-87-92329-52-3.
7. Sun, Z. and I. F. Akyildiz, "Underground wireless communications using magnetic induction," Proc. IEEE International Conference on Communications (ICC), 1-5, 2009.
8. Akyildiz, I. F. and E. P. Stuntebeck, "Wireless underground sensor networks: Research challenges," Ad Hoc Networks Journal, Vol. 4, 669-686, Elsevier, 2006.
9. Li, L., M. C. Vuran, and I. F. Akyildiz, "Characteristics of underground channel for wireless underground sensor network," Proc. Med-Hoc Net, Corfu, Greece, Jun. 2007.
10. Agbinya, J. I., "Investigation of near field inductive communication system models, channels and experiments," Progress In Electromagnetics Research B, Vol. 49, 129-153, 2013.
11. Agbinya, J. I., N. Selvaraj, A. Ollett, S. Ibos, Y. Ooi-Sanchez, M. Brennan, and Z. Chaczko, "Characteristics of the magnetic bubble ‘Cone of Silence’ in near-field magnetic induction communications terminals," Journal of Battlefield Technology, Vol. 13, No. 1, 21-25, Mar. 2010.
12. Sun, Z. and I. F. Akyildiz, "Deployment algorithms for wireless underground sensor networks using magnetic induction," Global Telecommunications Conference (GLOBECOM), 1-5, IEEE, 2010.
13. Domingo, M., "Magnetic induction for underwater wireless communication networks," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 6, 2929-2939, 2012.
14. Masihpour, M., D. Franklin, and M. Abolhasan, "Multiplehop relay techniques for communication range extension in near-field magnetic induction communication systems," Journal of Networks, Vol. 8, No. 5, 2013.
15. Akyildiz, I., Z. Sun, and M. Vuran, "Signal propagation techniques for wireless underground communication networks," Physical Communication, Vol. 2, No. 3, 167-183, 2009.
16. Sun, Z. and I. Akyildiz, "Optimal deployment for magnetic induction-based wireless networks in challenged environments," IEEE Transactions on Wireless Communications, Vol. 12, No. 3, 996-1005, 2013.
17. Kisseleff, S., I. Akyildiz, and W. Gerstacker, "Throughput of the magnetic induction based wireless underground sensor networks: Key optimization techniques," IEEE Transactions on Communications, Vol. 62, No. 12, 4426-4439, 2014.
18. Akyildiz, I. F., P. Wang, and Z. Sun, "Realizing underwater communication through magnetic induction," IEEE Communications Magazine, Vol. 53, No. 11, 42-48, 2015.
19. Coillot, C., J. Moutoussamy, R. Lebourgeois, S. Ruocco, and G. Chanteur, "Principle and performance of a dual-band search coil magnetometer: A new instrument to investigate fluctuating magnetic fields in space," IEEE Sensors J., Vol. 10, No. 2, 255-260, 2010.
20. Grosz, A., E. Paperno, S. Amrusi, and B. Zadov, "A three-axial search coil magnetometer optimized for small size, low power, and low frequencies," IEEE Sensors J., Vol. 11, No. 4, 1088-1094, 2011.
21. Lukoschus, D., "Optimization theory for induction-coil magnetometers at higher frequencies," IEEE Transactions on Geoscience Electronics, Vol. 17, No. 3, 56-63, 1979.
22. Grosz, A. and E. Paperno, "Analytical optimization of low-frequency search coil magnetometers," IEEE Sensors J., Vol. 12, No. 8, 2719-2723, 2012.
23. Cavoit, C., "Closed loop applied to magnetic measurements in the range 1 of 0.1–50 MHz," Rev. Sci. Instrum., Vol. 77, No. 6, 2006, http://dx.doi.org/10.1063/1.2214693.
24. Tal, N., Y. Morag, and Y. Levron, "Increasing the sensitivity of search coil magnetometer by capacitive compensation," IEEE Sensors J., Vol. 16, No. 12, 4671-4672, 2016.
25. Nguyen, H., J. I. Agbinya, and J. Devlin, "Channel characterisation and link budget of MIMO configuration in near field magnetic communication," Int. J. Electron. Telecommun., Vol. 59, No. 3, 255-262, Aug. 2013.
26. Gottula, R. B., "Discrete-time implementation antenna design and MIMO for near-field magnetic induction communications,", 2012, http://hdl.lib.byu.edu/1877/etd5440.
27. Kim, H. J., J. Park, K. S. Oh, J. P. Choi, J. E. Jang, and J. W. Choi, "Near-field magnetic induction MIMO communication using heterogeneous multiplepole loop antenna array for higher data rate transmission," IEEE Transactions on Antennas and Propagation, Vol. 64, No. 5, 1952-1962, 2016.
28. Yenchek, M. R., G. T. Homce, N. W. Damiano, and J. R. Srednicki, "NIOSH-sponsored research in through-the-Earth communications for mines: A status report," IEEE Transactions on Industry Applications, Vol. 48, No. 5, 1700-1707, 2012.
29. Sarris, I. and A. R. Nix, "Design and performance assessment of high-capacity MIMO architectures in the presence of a line-of-sight component," IEEE Transactions on Vehicular Technology, Vol. 56, No. 4, 2194-2202, 2007.
30. Yu, K., M. Bengtsson, B. Ottersten, and M. Beach, "Narrowband MIMO channel modeling for LOS indoor scenarios," Proc. XXVIIth Trienn. Gen. Assem. Int. URSI, Aug. 2002.
31. Cottatellucci, L. and M. Debbah, "On the capacity of MIMO rice channels," Proc. 42nd Allerton Conf., 1506-1516, 2004.
32. Sakaguchi, K., H. Y. E. Chua, and K. Araki, "MIMO channel capacity in an indoor line-ofsight (LOS) environment," IEEE Transactions on Communications, Vol. E88-B, No. 7, 3010-3019, Jul. 2005.
33. Agbinya, J. I. and M. Masihpour, "Power equations and capacity performance of magnetic induction communication systems," Wireless Pers. Commun., Vol. 64, 831-845, 2012.
34. Elliot, R. S., "Electromagnetics in free space," Electromagnetics, Ch. 5, 314, McGraw-Hill, 1966.
35. Conway, J. T., "Inductance calculations for noncoaxial coils using Bessel functions," IEEE Trans. Mag., Vol. 43, No. 3, 1023-1034, 2007.
36. Conway, J. T., "Mutual inductance for an explicitly finite number of turns," Progress In Electromagnetics Research B, Vol. 28, 273-287, 2011.