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Introduction, History, and Selected Topics in Fundamental Theories of Metamaterials. N. Engheta and R. W. Ziolkowiski, Metamaterials – Physics and Engineering Explorations , Wiley, New York, Ch.1. Advisor: Prof. Ruey-Beei Wu Speaker: Ting-Yi Huang ( 黃定彝 ). Outlines. Introduction
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Introduction, History, and Selected Topics in Fundamental Theories of Metamaterials N. Engheta and R. W. Ziolkowiski, Metamaterials – Physics and Engineering Explorations, Wiley, New York, Ch.1 Advisor: Prof. Ruey-Beei Wu Speaker: Ting-Yi Huang (黃定彝)
Outlines • Introduction • Theory and simulation • Interesting phenomena • Basic Applications • Conclusion
Outlines • Introduction • History • Basic concepts • Theory and simulation • Interesting phenomena • Basic Applications • Conclusion
History (1/5) • Microwave experiment on twisted structures by Jagadis Chunder Bose, 1898 B: radiating box P: polarizer A: analyzer S, S’: screen R: receiver J. C. Bose, “On the rotation of plane of polarisation of electric waves by a twisted structure,” Proc. Roy. Soc., vol. 63, pp. 146–152, 1898.
History (2/5) • Artificial chiral media by embedding randomly oriented small wire helices in host media, Lindman, 1914 O: transmitter I: indicator B, U: metal tubes R: sensor dipole T: tuner V, G: display M: chiral medium I. V. Lindell, A. H. Sihvola, and J. Kurkijarvi, “Karl F. Lindman: The last Hertzian, and a Harbinger of electromagnetic chirality,” IEEE Antennas Propag. Mag., vol. 34, no. 3, pp. 24–30, 1992
History (3/5) • Lightweight microwave lenses by periodical spheres, disks, and strips, Kock, 1948 W. E. Kock, “Waveguide lens system,” U.S. Patent 2,596,251, May 13, 1952.
History (4/5) • Theoretical study on plane wave propagation in materials with negative permittivity and permeability, Veselago, 1967 V. G. Veselago, “The electrodynamics of substances with simultaneously negative values of ε and μ,” Sov. Phys. Uspekhi, vol. 10, no. 4, pp. 509–514, 1968. [Usp. Fiz. Nauk, vol. 92, pp. 517–526, 1967.]
History (5/5) • Anomalous refraction in composite medium, Smith and Schultz, 2000 R. A. Shelby, D. R. Smith, and S. Schultz, “Experimental verification of a negative index of refraction,” Science, vol. 292, no. 5514, pp. 77–79, 6 Apr. 2001
Basic Concepts (1/2) • Names and terminologies • Left-hand media • Media with negative refraction index • Backward-wave media • Double-negative (DNG) metamaterials
Basic Concepts (2/2) • Classification • Double positive (DPS) medium • Epsilon-negative (ENG) medium • Mu-negative (MNG) medium • Double-negative (DNG) medium
Outlines • Introduction • Theory and simulation • Material models • Wave parameters • FDTD simulations • Causality • Interesting phenomena • Basic Applications • Conclusion
Material Models (1/2) • Lorentz model : damping coefficient : coupling coefficient resonant at f0 for : electric susceptibility
Material Models (2/2) • Special cases producing negative ε • Debye model: small acceleration • Drude model: negligible restoring force – negative for – plasma frequency
Wave Parameters • DNG media with small loss • Wavenumber and impedance • Index of refraction
FDTD Simulations (1/2) • Finite-difference time-domain (FDTD) method … … K. S. Yee, “Numerical solution of initial boundary value problems involving Maxwell's equations in isotropic media,” IEEE Trans. Antennas Propagat., vol. 14, pp. 302-307, May 1966
FDTD Simulations (2/2) • Lossy Drude polarization/magnetization model • Model implementation in FDTD
Causality • Nondispersive DNG medium is noncausal
Outlines • Introduction • Theory and simulation • Interesting phenomena • Scattering • Backward waves • Negative refraction • Basic Applications • Conclusion
Scattering • Scattering with DNG slab • Growing evanescent wave in matched DNG slab
Negative Refraction (1/2) • Snell’s Law
Negative Refraction (2/2) • In DNG media • For matched low loss DNG slab
Outlines • Introduction • Theory and simulation • Interesting phenomena • Basic Applications • Phase compensation • Dispersion compensation • Subwavelength focusing • Zero index of refraction • Conclusion
Phase Compensation • Phase difference • Zero phase difference • Time-delayed WG with zero phase delay
Subwavelength Focusing (1/6) • Perfect focusing • Paraxial focusing y = 2d n=1 n=1 n=-1 n=-2 y = -2d
Subwavelength Focusing (2/6) • Perfect focus solution:
Subwavelength Focusing (3/6) • Paraxial foci
Subwavelength Focusing (4/6) • Source far from the slab
Subwavelength Focusing (5/6) • Gaussian beam with two different slabs
Subwavelength Focusing (6/6) • Planoconcave DNG lens
Zero Index of Refraction (1/3) • Matched zero-index medium • Maxwell’s equations Automatically satisfied for finite fields
Zero Index of Refraction (2/3) • Infinite cylindrical zero-index medium ⊙
Outlines • Introduction • Theory and simulation • Interesting phenomena • Basic Applications • Conclusion
Conclusion • Summary • Fundamental properties of DNG metamaterials • Interesting, unconventional features • Future work • More comprehensive review • Future potential applications