Design and Development of Vacuum-Sealed Waveguide Window for mm-wave and sub mm-wave Applications

This paper presents design and development of vacuum-sealed waveguide windows at mm-wave and sub mm-wave frequencies and associated realization challenges. The vacuum-sealed waveguide windows are essential to isolate various environmental conditions required for characterization of microwave front-ends. The proposed window comprises of quarter wavelength spacer sandwiched between two epoxy filled shims. The vacuum-sealed waveguide windows are designed at four different frequency bands ranging from WR8.0 to WR2.8 and the measured leak-rate of developed waveguide windows is ≤1x 10-8 atm-cc/s. Detailed design methodology including simulations, parametric analysis, fabrication challenges, characterization results and analysis of these windows is discussed in this paper.