Near-field plates: subdiffraction focusing with patterned surfaces.
Using a patterned, grating-like plate to control the electromagnetic near field, we demonstrate focusing well beyond the diffraction limit at approximately 1 gigahertz. The near-field plate consists of only capacitive elements and focuses microwaves emanating from a cylindrical source to a spot of size approximately lambda/20 (half-power beamwidth), where lambda is the free-space wavelength. These plates will find application in antennas, beam-shaping devices, nonradiative wireless power-transfer systems, microscopy, and lithography.
Grbic
Anthony
A
Radiation Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2122, USA. agrbic@umich.edu
Jiang
Lei
L
Merlin
Roberto
R