Engineered materials with unusual electromagnetic properties such as a negative index of refraction
Our group has pioneered the method of loaded transmission lines to synthesize artificial materials (metamaterials) with unusual electromagnetic properties such as a negative index of refraction . These transmission-line metamaterials offer unique advantages such as small losses and large operating bandwidths . We are utilizing the unique advantages and properties of these metamaterials to synthesize some novel microwave devices and structures. These include:
a) The first ever Veselago-Pendry lens than can overcome the diffraction limit .
b) The first ever 3-dimensional Veselago-Pendry lens that can overcome the diffraction limit .
c) Novel couplers than support "complex waves" and exhibit high coupling levels and high directivity .
d) Novel phase-shifting lines that exhibit a very short length and can provide positive/zero/negative phase shifts with small losses .
e) Compact and broadband power-dividers/combiners .
f) Multi-band lines for synthesizing multi-band passives for emerging wireless applications ,.
g) The first ever combination of CMOS ICs and metamaterials to synthesize low-beam squinting phase-shifters and phased arrays ,.
e) The first artificial transmission lines that exhibit simultaneously a negative phase and negative group index .
Such structures have unique properties that can be used for delay equalization on interconnects, for broadband phase shifters and for instrumentation .
Exciting opportunities are awaiting for the invention of the next generation of these novel devices and their integration in sub-systems and systems. Particular emphasis will be placed on the combination of metamaterials and electronics.
DEVICE RESULTS AND STRUCTURES
 G.V. Eleftheriades, A.K. Iyer and P.C. Kremer, "Planar negative refractive index media using periodically L-C loaded transmission lines", IEEE Trans. on Microwave Theory and Techniques, vol. 50, no. 12, pp. 2702-2712, Dec. 2002 (designated by ISI as a 'Hot Paper in Engineering', March 2004, 'the fast moving front paper in Computer Science for September 2005' and 'the fast moving front paper in Engineering' for January 2008).
 G.V. Eleftheriades, "Analysis of bandwidth and loss in negative-refractive-index transmission-line (NRI-TL) media using coupled resonators", IEEE Microwave and Wireless Components Letters, pp. 412-414, June 2007.
 A. Grbic and G.V. Eleftheriades, "Overcoming the diffraction limit with a planar left-handed transmission-line lens", Physical Review Letters, vol. 92, no. 11, pp. 117403 , March 19, 2004 (featured on the front cover).
 R. Islam, F. Elek and G.V. Eleftheriades, "A coupled-line metamaterial coupler having co-directional phase but contra-directional power flow", (Electronics Letters), vol. 40, no. 5, pp. 315-317, March 04, 2004.
 M.A. Antoniades and G.V. Eleftheriades, "Compact, linear, lead/lag metamaterial phase shifters for broadband applications", IEEE Antennas and Wireless Propagation Letters, vol. 2, issue 7, pp. 103-106, July 2003.
 M. Antoniades and G.V. Eleftheriades, "A broadband series power divider using zero-degree metamaterial phase-shifting lines", IEEE Microwave and Wireless Component Letters, vol. 15, pp. 808- 810, Nov. 2005.
 G.V. Eleftheriades, "A generalized negative-refractive-index transmission-line (NRI-TL) metamaterial for dual-band and quad-band applications", IEEE Microwave and Wireless Components Letters, vol. 17, pp. 415-417, June 2007.
 A. C. Papanastasiou, G. E. Georghiou and G. V. Eleftheriades, "A quad-band Wilkinson power divider using NRI transmission lines", IEEE Microwave and Wireless Components Letters, vol. 18, pp. 521-523, August 2008.
 M. A.Y. Abdalla, K. Phang, and G.V. Eleftheriades, "A planar electronically steerable patch array using tunable PRI/NRI phase shifters;, IEEE Trans. on Microwave Theory and Techniques, vol. 57, pp. 531-541, March 2009.
 M. Abdalla, K. P hang, and G.V. Eleftheriades, " A compact highly-reconfigurable CMOS MMIC directional coupler", IEEE Trans. on Microwave Theory and Techniques, vol. 56, pp. 305-319, Feb. 2008.
 O. Siddiqui, M. Mojahedi, and G.V. Eleftheriades, "Periodically loaded transmission line with effective negative refractive index and negative group velocity", IEEE Trans. on Antennas and Propagation (Special Issue on Metamaterials), vol. 51, no. 10, pp. 2619-2625, Oct. 2003.
 H. Mirzaei, R. Islam and G.V. Eleftheriades, "Anomalous negative group velocity in coupled positive-index/negative-index guides supporting complex modes ", IEEE Trans. on Antennas and Propagation, vol. 59, pp. 3412-3420, Sept. 2011.