Increase of the transmission in cut-off metallic hole arrays

In this letter, the phenomenon of extraordinary transmission through arrays of subwavelength holes in the microwave range is demonstrated. It is also shown that the magnitude of the transmission is strongly dependent on the number of holes in the sample. Prototypes have been designed and fabricated in an Al plate. The transmission response is measured with a millimeter wave quasi-optical vector network analyzer in the range between 40 and 70GHz. These measurements show a resonant total transmission at wavelengths close to the period of the array which depends strongly on the number of resonant holes. These results can give rise to interesting applications such as frequency selective surfaces and other quasi-optical structures.