Real Time Rotatable Waveguide Twist Using Contactless Stacked Air-Gapped Waveguides

A novel real-time rotatable rectangular waveguide twist is presented in this letter. The proposed waveguide twist is based on the contactless waveguide flange technique. The electromagnetic wave is confined inside the rectangular waveguide if the air gap between the two flanges does not exceed the maximum allowed distance. Therefore, relative rotation between the contactless flanges is allowed. Seven rectangular waveguide plates with smooth surface on one side of it but bed of nails on the other side are manufactured. They are stacked together layer by layer and are placed into a hollow circular housing. Two adjacent plates have a maximum twist angle of 15°. Therefore, the proposed stacked twist can realize any twist angle between 90°. A Ka-band prototype is designed, manufactured, and tested. The measured return loss is better than 15 dB, while the insertion loss is better than 0.3 dB over the whole Ka-band.