URSI 2009, XXIV Simposium Nacional de la Unión Científica Internacional de Radio, Santander
This document presents the design and characterization of a waveguide transition mounted in a cryostat window for cryogenic RF measurements in the Ka band. This waveguide transition comprises a vacuum window that enables to separate two environments with very different pressures, and a thermal break that isolates the test area inside the cryostat from the heat coming into it through the waveguide. Waveguide chokes are designed both in vacuum window and thermal break to improve RF response due to existing gaps between waveguide flanges. The transition, designed for the WR28 waveguide, covers the full band 26 – 40 GHz showing excellent return and insertion losses as well as a good thermal isolation and low air leakage.
