Surface-topography-induced enhanced transmission and directivity of microwave radiation through a subwavelength circular metal aperture
Lockyear, Matthew J.
Hibbins, Alastair P.
Sambles, J. Roy
Lawrence, Christopher R.
University of Exeter; QinetiQ Ltd, Farnborough
Applied Physics Letters
American Institute of Physics
Strongly enhanced transmission of microwave radiation (λ0~5 mm) is observed through a single subwavelength circular aperture of diameter d = 2.5 mm in a metallic plate. The phenomenon is caused by resonant excitation of electromagnetic surface waves supported by four concentric grooves surrounding the aperture on the illuminated side of the sample. It is also shown that similar surface patterning on the output face of the sample results in very strong angular confinement (directivity) of the transmitted beam. A finite element code is used to investigate the electromagnetic fields on both the illuminated and the exit side of the structure, the predictions from which show excellent agreement with the experimental results.
Copyright © 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 84 (2004) and may be found at http://link.aip.org/link/?APPLAB/84/2040/1
84 (12), pp. 2040-2042