volume | PIER Journals

Abstract

Two focus-scanning schemes, viz. lens-fixed scanning scheme and lens-combined scheme, are proposed for near-field target detection and imaging. Specific lens size must be determined for future lens building in order to achieve desired imaging resolution and convenient data acquisition. Influence of LHM lens size on the performance of two different focus-scanning schemes are investigated and compared by simulating the detection of a perfect electric conductor target of diameter of 2 mm. Numerical simulations indicate that the lens-combined scanning system using thick LHM lens of thickness of two wavelengths requires at least a length of one wavelength to achieve resolution better than 0.4 wavelengths, while the lens-fixed scanning system requires a lens of lengthof approximately 3 wavelengths. When a thin LHM lens is used, high imaging resolution is not a consequent result for the focus-scanning approaches, although thin lens generally yields high focusing resolution. Some guidelines on the selection of length and thickness of flat LHM lens are reported.

1. Veselago, V. G., "The electrodynamics of substances with simultaneously negative values of ε and μ," Sov. Phys. Usp., Vol. 10, No. 4, 509-514, 1968.
doi:10.1070/PU1968v010n04ABEH003699

2. Caloz, C. and T. Itoh, "Metamaterials for high-frequency electronics," Proc. IEEE, Vol. 93, No. 10, 1744-1751, 2005.
doi:10.1109/JPROC.2005.853540

3. Engheta, N. and R. W. Ziolkowski, "A positive future for double-negative metamaterials," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 4, 1535-1556, 2005.
doi:10.1109/TMTT.2005.845188

4. Grzegorczyk, T. M. and J. A. Kong, "Review of left-handed metamaterials: Evolution from theoretical and numerical studies to potential applications," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 14, 2053-2064, 2006.
doi:10.1163/156939306779322620

5. Pendry, J. B., "Negative refraction makes a perfect lens," Phys. Rev. Lett., Vol. 85, 3966-3969, 2000.
doi:10.1103/PhysRevLett.85.3966

6. Cummer, S. A., "Simulated causal subwavelengthfo cusing by a negative refractive index slab," Appl. Phys. Lett., Vol. 82, 1503-1505, 2003.
doi:10.1063/1.1554778

7. Rao, X. S. and C. K. Ong, "Subwavelengthimaging by a left-handed material superlens," Phys. Rev. E, Vol. 68, 0676011-3, 2003.

8. Fang, N. and X. Zhang, "Imaging properties of a metamaterial superlens," Appl. Phys. Lett., Vol. 82, 161-163, 2003.
doi:10.1063/1.1536712

9. Feise, M. W. and Y. S. Kivshar, "Sub-wavelength imaging with a left-handed material flat lens," Phys. Lett. A, Vol. 334, 326-330, 2005.
doi:10.1016/j.physleta.2004.11.031

10. Yu, G. X. and T. J. Cui, "Imaging and localization properties of LHM superlens excited by 3D horizontal electric dipoles," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 1, 35-46, 2007.
doi:10.1163/156939307779391795

11. Lagarkov, A. N. and V. N. Kissel, "Near-perfect imaging in a focusing system based on a left-handed-material plate," Phys. Rev. Lett., Vol. 92, 774011-4, 2004.

12. Parimi, P., W. T. Lu, P. Vodo, and S. Sridhar, "Imaging by flat lens using negative refraction," Nature, Vol. 426, 404, 2003.
doi:10.1038/426404a

13. Grbic, A. and G. V. Eleftheriades, "Overcoming the diffraction limit witha planar left-handed transmission-line lens," Phys. Rev. Lett., Vol. 92, 1174031-4, 2004.
doi:10.1103/PhysRevLett.92.117403

14. Ran, L. X., J. Huangfu, H. Chen, X. M. Zhang, K.-S. Cheng, T. M. Grzegorczyk, and J. A. Kong, "Experimental study on several left-handed metamaterials," Progress In Electromagnetics Research, Vol. 51, 249-279, 2005.
doi:10.2528/PIER04040502

15. Aydin, K., I. Bulu, and E. Ozbay, "Focusing of electromagnetic waves by a left-handed metamaterial flat lens," Opt. Express, Vol. 13, 8753-8759, 2005.
doi:10.1364/OPEX.13.008753

16. Wang, G., J. Fang, and X. T. Dong, "Resolution of near-field target detection and imaging by using flat LHM lens," IEEE Trans. Antennas Propagat., Vol. 55, No. 12, 3534-3541, 2007.
doi:10.1109/TAP.2007.910365

17. Wang, G., J. Fang, and X. T. Dong, "Refocusing of backscattered microwaves in target detection by using LHM flat lens," Opt. Express, Vol. 15, No. 6, 3312-3317, 2007.
doi:10.1364/OE.15.003312

18. Chen, L., S. He, and L. Shen, "Finite-size effects of a left-handed material slab on the image quality," Phys. Rev. Lett., Vol. 92, No. 10, 107404-1-4, 2004.

19. Chen, J. J., T. M. Grzegoczyk, B.-I. Wu, and J. A. Kong, "Imaging properties of finite-size left-handed material slabs," Phys. Rev. E, Vol. 74, 046615, 2006.
doi:10.1103/PhysRevE.74.046615

20. Kissel, V. N. and A. N. Lagarkov, "Superresolution in left-handed composite structures: From homogenization to a detailed electrodynamic description," Phys. Rev. B, Vol. 72, 085111, 2005.
doi:10.1103/PhysRevB.72.085111

Prof. Gang Wang

Dr. Yu Gong

Dr. Hongjin Wang