Waveguide adapter with contactless flange for operation in the millimeter wavelength range

Methods of increasing accuracy of the results of measuring the electrical parameters of waveguide devices operating in the upper region of the millimeter-wave range are reviewed. It is shown that accuracy and reliability of measuring the electrical parameters of waveguide devices depend on the quality of contact between waveguide flanges, since leakage of electromagnetic radiation through the gaps poses a significant problem and can lead to unreliable results in measuring the insertion losses and voltage standing-wave ratio. Therefore, the requirements related to the quality of contact between the measurement system and tested device operating in the millimeter range are becoming more stringent. A contactless waveguide adapter flange for operating in the millimeter has been developed that is insensitive to an air gap in the connection with the tested device. The waveguide adapter with contactless flange constitutes a section of a standard rectangular WR10 waveguide bounded by a standard UG-387 flange on one side and by the proposed contactless flange with a pin-like structure on the other side. By using the proposed adapter with a contactless flange, it becomes possible to minimize issues related to measuring direct and reverse losses caused by an imperfect contact or lack thereof when connecting two waveguide flanges. This type of flange connection can be used to perform express measurements, since no screw fastening of the flange is required. A comparative analysis of the standard and contactless-flange adapters was performed in a WR10 waveguide channel. The performance efficiency of the contactless connection was confirmed experimentally within the entire operating range of 75 to 110 GHz with a non-uniform (on one side) 100 μm gap in the waveguide connection. The use of a contactless-flange adapter makes it possible to perform faster and more accurate measurements of the electrical parameters of the tested devices. This adapter is indispensable when performing a quick certification of the millimeter-range waveguide devices using modern metrological tools (e.g., vector and scalar network analyzers).