Slow waves caused by cuts perpendicular to a single subwavelength slit in metal

Resonant transmission of microwaves through a subwavelength slit in a thick metal plate, into which subwavelength cuts have been made, is explored. Two orientations of the cuts, parallel and perpendicular to the long axis of the slit, are examined. The results show that the slits act as though filled with a medium with anisotropic effective relative permeability which at low mode numbers has the two values similar to( 1, 9.1), increasing to similar to( 1, 14.4) for higher mode numbers.