Departmental Papers (ESE)


Here, we explore theoretically the concept of enhanced directivity from electrically small subwavelength radiators containing negative-parameter materials, such as plasmonic materials with negative permittivity at THz, infrared and optical frequencies. In particular, we study higher order plasmonic resonances of a subwavelength core-shell spherical nano-antenna, and we analyze the near-zone field distributions and far-field radiation patterns of such a structure when it is excited by a small dipole source, demonstrating analytically and numerically the possibility of having highly directive patterns from a nano-structure with electrically small dimensions. Radiation characteristics and intrinsic limitations on performance are analyzed in detail, and a potential application of this novel technique for super-resolution detection of the displacement of a nano-object is also pointed out.

Document Type

Journal Article

Date of this Version

November 2007


Copyright 2008 IEEE. Reprinted from IEEE Transactions on Antennas and Propagation, Volume 55, Issue 11, Part 1, November 2007, 3027-3039.

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metamaterials, nanoantennas, optical frequencies, super-directivity



Date Posted: 02 September 2008

This document has been peer reviewed.