An innovative waveguide interface for millimeter wave and sub-millimeter wave applications

An inherent problem with waveguide interface above 110 GHz is waveguide flange misalignment. This misalignment occurs as the result of machining tolerances. Under the current MIL SPECS specified tolerances and the standard alignment pins to alignment holes method, the smaller the waveguide, the greater the relative misalignment and the greater the impact to the system electrical performance. At 680 GHz, the flange and the waveguide can be misaligned as much as a quarter (¿) wavelength - that is, half (1/2) the physical waveguide dimension. This paper describes an innovative waveguide interface design that offers improved performance repeatability, VSWR frequency response and a more robust mechanical handling without the use of conventional alignment pins to alignment holes technique. Integrated into the design are ease of manufacturing and ease of alignment. The uniqueness of the novel waveguide interface is discussed and the performance of the WR-05 (140 GHz to 220 GHz) waveguide interface is presented.