This paper presents the design of an 8-element linear array for Adaptive Antenna applications using the Least Mean Square (LMS) algorithm towards improving the directive gain, beam steering capabilities, half-power beamwidth, sidelobe level, and bandwidth of array. A conventional patch antenna is optimized to operate at 3.6 GHz (5G applications) with two symmetrical slots and Quarter Wave Transformer for feeding, and this design is extended up to 8 elements using CST Microwave Studio parameterization. The Return Loss (S11), Directivity, HPBW and VSWR of the antenna array are observed for the 2, 4, and 8 element adaptive array. The inter-element spacing for resulting eight-element antenna array geometry is optimized to obtain maximum directive gain. This geometry appears promising in improving the directive gain from 7.6 dBi to 15.1 dBi for a single element to eight elements respectively. Further, the LMS algorithm is used to compute the optimal complex weights, considering different angles for the desired User (+45˚ and -45˚) and Interferer (+20˚ and -20˚) during MATLAB simulation, and then these optimal weights are fed to antenna elements using CST for beam steering in a different direction. Maximas in the direction of user and nulls in the direction of interferer are obtained using CST software and found closely matching with MATLAB results.
2. Srar, J. A. S. and K.-S. Chung, "Adaptive array beam forming using combined RLS-LMS algorithm," Proceedings of APCC 2008 IEICE 08 SB 0083, 2008.
3. Godara, L. C., "Application of antenna arrays to mobile communications, part-II: Beam-forming and direction-of-arrival considerations," Proceedings of the IEEE, Vol. 85, No. 8, 1195-1245, August 1997. doi:10.1109/5.622504
4. Haji, I. A., Md. Rafiqul Islam, A. H. M. Zahirul Alam, O. O. Khalifa, and S. Khan, "Design and optimization of linear array antenna based on the analysis of direction of arrival (DOA) estimation and beamforming algorithms," (ICCCE 2010), Kuala Lumpur, Malaysia, May 11-13, 2010.
5. Wang, H., Z. Zhang, and Z. Feng, "A Beam-switching antenna array with shaped radiation patterns," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 818-821, 2012. doi:10.1109/LAWP.2012.2206362
6. Amsavalli, A. and K. R. Kashwan, "Smart patch antenna array for uplink in 4G mobile communication based on LMS algorithm for DS-CDMA technique," Journal of Convergence Information Technology (JCIT), Vol. 9, No. 1, January 2014.
7. Balanis, C. A., Antenna Theory: Analysis and Design, 3rd Ed., Wiley, Hoboken, NJ, 2005, ISBN 047166782X (hbk).
8. Hossaini, S., M. T. Islam, and S. Serikawa, "Adaptive beam-forming algorithms for smart antenna systems," International Conference on Control, Automation and Systems 2008 in COEX, Seoul, Korea, October 14–17, 2008.
9. Dungriyal, K., S. Ananad, and D. Sriram Kumar, "Performance of MIR-LMS algorithm for beamforming in smart antenna," IJISET, Vol. 1, No. 5, July 2014.
10. Navia-Vzquez, A., M. M. Beamforming, L. E. Garca-Muoz, and C. G. Christodoulou, "Approximate Kernel orthogonalization for antenna array processing," IEEE Transactions on Antennas and Propagation, Vol. 58, No. 12, 3942-3950, December 2010. doi:10.1109/TAP.2010.2078458
11. Navia-Vzquez, A., M. Martnez-Ramn, L. E. Garca-Muoz, and C. G. Christodoulou, "Adaptive approximate Kernel orthogonalization for antenna array processing," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 8, 4091-4100, August 2013. doi:10.1109/TAP.2013.2263276
12. A white paper on ``Enabling 5G in India,'', February 22, 2019.
13. Zainarry, S. N. M., N. Nguyen-Trong, and C. Fumeaux, "A frequency- and pattern-reconfigurable two-element array antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 17, No. 4, 617-620, April 2018. doi:10.1109/LAWP.2018.2806355
14. Gan, Z., Z.-H. Tu, and Z.-M. Xie, "Pattern-reconfigurable unidirectional dipole antenna array fed by SIW coupler for millimeter-wave application," IEEE Access, Vol. 6, 22401-22407, 2018. doi:10.1109/ACCESS.2018.2810194
15. Chang, L., H.-Y. Yang, H. N. Chu, and T.-G. Ma, "Two-element retro-directive/beam-switching array using dual-mode coupler," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 2240-2243, 2017. doi:10.1109/LAWP.2017.2710086
16. Chou, H.-T. and C.-T. Yu, "Design of phased array antennas with beam switching capability in the near-field focus applications," IET Microwaves, Antennas & Propagation, Vol. 9, No. 11, 1120-1127, The Institution of Engineering and Technology, 2015, ISSN 1751-8725. doi:10.1049/iet-map.2015.0034
17. Radaydeh, R. M. and M.-S. Alouini, "Comparisons of receive array interference reduction techniques under erroneous generalized transmit beamforming," IEEE Transactions on Communications, Vol. 62, No. 2, 600-615, February 2014. doi:10.1109/TCOMM.2013.122813.130275