In this paper, a novel technique for electronic beam steering in time modulated linear array (TMLA) is proposed. The beam steering technique is realized at the first sideband by controlling the switch-on time sequences of each element in the TMLA without using phase shifters. The differential evolution (DE) algorithm is employed to improve the gain and suppress the sidelobe levels (SLLs) at both the center frequency and the first sideband, simultaneously. An S-band 8-element double-layered printed dipole linear array was used to verify the technique experimentally. Measured results are compared with numerical data, and good agreement is reported. Moreover, some simulation results on the binary phase shift keying (BPSK) modulated signals arriving from different directions received by the proposed approach are presented, which validates the application of the proposed beam steering technique.
2. Yang, S., Y. B. Gan, and A. Qing, "Sideband suppression in time-modulated linear arrays by the differential evolution algorithm," IEEE Antennas Wireless Propagat. Lett., Vol. 1, 173-175, 2002.
3. Yang, S., Y. B. Gan, and P. K. Tan, "Comparative study of low sidelobe time modulated linear arrays with different time schemes," Journal of Electromagnetic Waves and Applications, Vol. 18, No. 11, 1443-1458, 2004.
4. Yang, S., Y. B. Gan, A. Qing, and P. K. Tan, "Design of a uniform amplitude time modulated linear array with optimized time sequences," IEEE Trans. Antennas Propagat., Vol. 53, No. 7, 2337-2339, July 2005.
5. Fondevila, J., J. C. Bregains, F. Ares, and E. Moreno, "Application of time modulation in the synthesis of sum and difference patterns by using linear arrays," Microwave. Opt. Technol. Lett., Vol. 48, No. 5, 829-832.
6. Shanks, H. E. and A new technique for electronic scanning, IEEE Trans. Antennas Propagat., Vol. 9, No. 2, 162-166, March 1961.
7. Tennant, A. and B. Chambers, "A two-element time-modulated array with direction-¯nding properties," IEEE Antennas Wireless Propagat. Lett., Vol. 6, 64-65, 2007.
8. Yang, S., Y. B. Gan, and P. K. Tan, "Evaluation of directivity and gain for time modulated linear antenna arrays," Microwave Opt. Technol. Lett., Vol. 42, No. 2, 167-171, July 2004.
9. Qing, A., "Electromagnetic inverse scattering of multiple two-dimensional perfectly conducting objects by the differential evolution strategy," IEEE Trans. Antenna Propagat., Vol. 51, No. 6, 1251-1262, June 2003.
10. Chen, Y., S. Yang, and Z. Nie, "The application of a modified di®erential evolution strategy to some array pattern synthesis problems," IEEE Trans. Antennas Propagat., Vol. 56, No. 7, 1919-1927.
11. Shahoei, H., H. Ghafoori-Fard, and A. Rostami, "A novel design methodology of multiclad single mode optical fiber for broadband optical networks," Progress In Electromagnetics Research, Vol. 80, 253-275, 2008.
12. Panduro, M. A. and C. Del Rio Bocio, "Design of beam-forming networks for scannable multi-beam antenna arrays using CORPS," Progress In Electromagnetics Research, Vol. 84, 173-188, 2008.
13. Li, J.-Y. and J. L. Guo, "Optimization technique using differential evolution for Yagi-Uda antennas," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 4, 449-461, 2009.
14. Bregains, J. C., J. Fondevila-Gomez, G. Franceschetti, and F. Ares, "Signal radiation and power losses of time-modulated arrays," IEEE Trans. Antennas Propagat., Vol. 56, No. 6, 1799-1804, June 2008.
15. Li, G., G., S. Yang, Z. Zhao, and Z. Nie, "A study of AM and FM signal reception of time modulated linear antenna arrays," Progress In Electromagnetics Research Letter, Vol. 7, 171-181, 2009.
16. Zhou, Z., S. Yang, and Z. Nie, "A novel broadband printed dipole antenna with low cross-polarization," IEEE Trans. Antenna Propagat., Vol. 55, No. 11, 3091-3093, November 2007.