Comparing Standardized and Manufacturers’ Interfaces for Waveguides Used at Submillimeter Wavelengths

This article presents a comparison between the specified dimensions given in document standards (IEEE Std 1785.2-2016) and the measured dimensions for interfaces used with rectangular metallic waveguides at submillimeter wavelengths. The standardized dimensions of these waveguide interfaces are compared with several waveguides in the WM-380 band (500-750 GHz) manufactured by two different companies. The measured electrical performance (in terms of reflection coefficient) for these waveguide interfaces is also compared with values given in documentary standards. The article shows that although the manufactured waveguides do not strictly adhere to the dimensions given in the standard, very good electrical performance is still achievable by using slightly different dimensions for the manufactured waveguide interfaces. The use of additional alignment dowel pins (as specified in the IEEE standard) further improves the electrical performance of these interfaces.