MONOLITHIC HOLLOW WAVEGUIDE AND METHOD AND APPARATUS FOR MAKING THE SAME

摘要

The present application discloses a method and apparatus for making a low cost and highly efficient hollow waveguide (30) for transmitting electromagnetic radiation. The waveguide (30) is made from a solid substrate monolithic hollow tube (10) with a reflectivity enhancing dielectric film (40) formed directly over the inner surface (25). The film can be formed by native chemical reactions, with the material of the monolithic, hollow tube (10). The present application also discloses a method of polishing and cleaning the inner surface (25) of the hollow tube (10). One of the problems identified with the hollow metallic waveguide (30) has been the poor surface finish on the inner wall of the hollow tube (10) which results from the processes used to fabricate the metallic tube into final form. The coated reflectivity enhancing dielectric films more or less duplicate the surface roughness in the as formed tube thus seriously affecting the performance of the waveguide especially at the shorter wavelengths. The interior surface (25) of the as received metal tubes can be significantly improved by chemically polishing and cleaning the tube and thereby improving the transmission characteristic of the waveguides (30) for both infrared and visible wavelengths.