volume | PIER Journals

Abstract

In most practical applications of the phased array antennas, the generated nulls toward the interfering signals should have enough depth and width to accommodate fluctuations in frequency and direction of the interferer. Due to these fluctuations, the nulls can be easily deviated from its desired angular locations in the traditional adaptive nulling arrays since the nulls are very sharp and sensitive. An innovative technique for wide nulling arrays has been recently presented. The wide nulls can be introduced by setting properly the excitation coefficients of the two edge elements of the antenna array. In this paper, the effect of frequency fluctuation on the nulling performance is investigated. By generating wide and deep nulls toward and around the interference directions, the proposed method provides robustness against frequency fluctuation. Simulation results in realistic situations with frequency fluctuation are presented to illustrate the performance of the proposed technique. Comparisons with the standard fully adaptive nulling array are shown.

1. Applebaum, S. P., Adaptive arrays and Propagat., Vol. 24, 585-598, IEEE Trans. on Antennas, Sep. 1976.

2. Steyskal, H., R. A. Shore, and R. L. Haupt, Methods for null control and their effects on the radiation pattern, Vol. 34, 404-409, IEEE Trans. on Antennas and Propagat., 1986.

3. Lu, Y. and B. K. Yeo, "Adaptive wide null steering for digital beam forming array with the complex coded genetic algorithm," IEEE Int. Conf. on Phased Array Systems and Technology, 557-560, 2000. Google Scholar

4. Haupt , R. L., "Phase-only adaptive nulling with a genetic algorithm," IEEE Trans. on Antennas and Propagat., Vol. 45, No. 6, 1009-1015, 1997.
doi:10.1109/8.585749 Google Scholar

5. Li, W.-T., X.-W. Shi, L. Xu, and Y.-Q. Hei, "Improved GA and PSO culled hybrid algorithm for antenna array pattern synthesis," Progress In Electromagnetics Research, Vol. 80, 461-476, 2008.
doi:10.2528/PIER07121503 Google Scholar

6. Morabito, A. F. and P. Rocca, "Optimal synthesis of sum and difference patterns with arbitrary sidelobes subject to common excitations constraints," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 623-626, Jul. 2010.
doi:10.1109/LAWP.2010.2053832 Google Scholar

7. Mangoud, M. A.-A. and H. M. Elragal, "Antenna array pattern synthesis and wide null control using enhanced particle swarm optimization," Progress In Electromagnetics Research B, Vol. 17, 1-14, 2009.
doi:10.2528/PIERB09070205 Google Scholar

8. Mouhamadou, M., P. Vaudon, and M. Rammal, "Smart antenna array patterns synthesis: Null steering and multi-user beamforming by phase control ," Progress In Electromagnetics Research, Vol. 60, 95-106, 2006.
doi:10.2528/PIER05112801 Google Scholar

9. Mohammed, J. R., "Phased array antenna with ultra-low sidelobes," Electronics Letters, Vol. 49, No. 17, 18-19, 2013.
doi:10.1049/el.2013.1642 Google Scholar

10. Compton, R. T., Adaptive Antennas: Concepts and Performance, Prentice-Hall, 1987.

11. Monzingo, R. A., R. L. Haupt, and T. W. Miller, Introduction to Adaptive Arrays, 2nd Ed., SciTech Publishing, 2011.

12. Van Veen, B. D. and K. M. Buckley, "Beam forming: A versatile approach to spatial filtering," IEEE ASSP Mag., Vol. 5, No. 2, 4-24, Apr. 1988.
doi:10.1109/53.665 Google Scholar

13. Morgan, D., "Partially adaptive array techniques," IEEE Trans. on Antennas and Propagat., Vol. 26, No. 6, 823-833, 1978.
doi:10.1109/TAP.1978.1141952 Google Scholar

14. Haupt, R. L., "Adaptive nulling with weight constraints," Progress In Electromagnetics Research B, Vol. 26, 23-38, 2010.
doi:10.2528/PIERB10070804 Google Scholar

15. Mohammed, J. R. and K. H. Sayidmarie, "A new technique for obtaining wide-angular nulling in the sum and difference patterns of monopulse antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 1242-1245, 2012. Google Scholar

16. Balanis, C. A., Modern Antenna Handbook, John Wiley, 2008.
doi:10.1002/9780470294154

Prof. Khalil Hassan Sayidmarie

Prof. Jafar Ramadhan Mohammed