Remarkable transmission of microwaves through a wall of long metallic bricks

The transmitted intensity of a microwave beam through a thick continuous me tal wall will be effectively zero due to the almost complete exclusion of t he electric field from the metal. However, it is shown here that by removin g less than 20% of the wall material to produce a regular array of bricks, up to 90% of the radiation is transmitted, despite the gaps between the bri cks being less than 5% of the incident wavelength. This result is attribute d to the excitation of a set of resonant waves along the cavity length thro ugh the coupling together of surface-plasmon modes across its width. (C) 20 01 American Institute of Physics.