Method of waveguides with conductive vacuum coating fabrication

Presented is the way of fabrication of waveguides and waveguide elements using the electroformed method of applying conductive vacuum coating that meets the technical requirements imposed on the waveguide elements: the minimum ratio of a standing wave voltage (VSWR) - 1,03-1,05; minimal loss of energy during the passage of the wave is not more than 5 ∙ 10 -2dB; electrokinetically flange products - up to 40-50 dB. Also the demands on the roughness of the inner surface of the channel (Ra is not more than 0.2 μm) and the deviation from the nominal size in the range of ±0,01 mm. The paper uses the method of manufacturing of a waveguide millimeter range, including the manufacture of the mandrel of aluminum alloy, the outer surface of which follows the shape of the internal channel of the waveguide, causing the mandrel which is a metal layer for forming conductive coating of the inner channel and the body of the waveguide, and further etching the mandrel. Investigated are the microstructure of the waveguide housing tract, the adhesion of the silver coating to the body of the waveguide and the measured roughness of the waveguide path are. Studies of the inner surface of the waveguide path in the presence of various impurities are made. The technology of vacuum deposition of the coating on the mandrel and capacity copper waveguide housing tract with subsequent etching of the mandrel has been developed. In this way it is possible to make the waveguides and waveguide elements tracts complex cross-sections. The conductive coatings, deposited by vacuum method, becomes dense and homogeneous, no absorption, and prevents chemical contamination of the coatings, resulting in reduced energy loss when passing waves and improves the quality of the transmitted signal. This method was made a waveguide of circular cross section with a diameter of 10 mm and length of 120 mm which has high adhesion with a conductive coating to the body of the waveguide.