Surface wave resonances supported on a square array of square metallic pillars

A family of transverse-magnetic surface waves is shown to be supported at microwave frequencies by a square array of subwavelength square cross-section metal pillars on a conducting ground plane. These surface waves are experimentally characterised with a collimated microwave beam apparatus that utilises a pair of two-dimensional parabolic mirrors positioned on the sample surface. The dispersion of the modes, each associated with a quantisation of the electromagnetic field in the depth of the slits, is fully characterised and compared with the predictions of finite element modelling. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691949]