In this article, an efficient method for the pattern synthesis of the linear antenna arrays with the prescribed null and multi-lobe Beamforming is presented. Multi-lobe pattern and adaptive nulling of the pattern is achieved by controlling only the phase of each array element. The proposed method is based on the Sequential Quadratic Programming (SQP) algorithm and the linear antenna array synthesis was modelled as a multi-ob jective optimization problem. Multi-ob jective optimization is concerned with the maximization (or minimization) of a vector of ob jectives functions in the directions of desired signal that can be sub ject of a number of constraints (in our case, the constraints can be imposed as the null in the direction of interfering signal). To verify the validity of the technique, several illustrative examples of uniform excited array patterns with the main beam is placed in the direction of the useful signal and null is placed in the direction of potential interferers, and multi-beam patterns are demonstrated.
2. Wells, M.C., "Increasing the capacity of GSM cellular radio using adaptive antennas," IEEProc. Commun., Vol. 143, No. 5, 304-310, 1996.
3. Lehne, P. H. and M. Pettersen, "An overview of smart antenna technology for mobile communications systems," IEE Communications Surveys, Vol. 2, No. 2, 2-13, 1999.
4. Baird, D. andG. Rassweiler, "Adaptive side lobe nulling using digitally controlled phase shifters," IEEE Trans.on Antennas and Propagation, Vol. 24, No. 5, 638-649, 1976.
5. Steyskal, H., "Synthesisof antenna pattern with prescribed nulls," IEEE Trans. on Antennas and Propagation, Vol. 31, 273-279, 1982.
6. Steyskal, H., "Simple method for pattern nulling by phase perturbation," IEEE Trans. on Antennas and Propagation, Vol. 31, 163-166, 1983.
7. Vu, T. B., "Simultaneous nulling in sum and difference patterns by amplitude control," IEEE Trans. on Antennas and Propagation, Vol. 34, 214-218, 1986.
8. Haupt, R. L., "Phase-only adaptive nulling with a genetic algorithm," IEEE Trans. on Antennas Propagation, Vol. 45, 1009-1015, 1997.
9. Liao, W. P. and F. L. Chu, "Array pattern nulling by phase and position perturbations with the use of the genetic algorithm," Microwave and Optical Technolo. Letters, Vol. 15, No. 4, 1997.
10. Vescovo, R., "Null synthesis by phase control for antenna array," Electronics Letters, Vol. 36, No. 33, 2000.
11. Karaboga, N., K. Güney, and A. Akdagli, "Null steering of linear antenna arrays with use of modified touring Ant Colony Optimization Algorithm," Int. J. RF and Microwave CAE, Vol. 12, 375-383, 2002.
12. Abu-Al-Nadi, D. I. and M. J. Mismar, "Genetically evolved phase-aggregation technique for linear arrays control," Progress In Electromagnetics Research, Vol. 43, 287-304, 2003.
13. Ismail, T. H., D. I. Abu-AL-Nadi, and M. J. Mismar, "Phase- only control for antenna pattern synthesis of linear arrays using Levenberg-Marquart algorithm," Electromagnetic., Vol. 24, 555-564, 2004.
14. Abu-Al-Nadi, D. I., T. H. Ismail, and M. J. Mismar, "Interference suppression by element position control of phased arrays using LM algorithm," Int. J. Electron. Commun. (AEÜ), 2005.
15. Boggs, P. T. and J. W. Tolle, "Sequential quadratic programming," Acta Numerica, 1-51, 1995.
16. Stoer, J., "Foundations of recursive quadratic programming methods for solving nonlinear program," Computational Mathematical Programming, Vol. 15, 1985.
17. Sunar, M., "A comparative study of multiobjective optimization methods in structural design," Turk. J. Engin. Environ. Sci., Vol. 25, 69-78, 2001.