Potential use of UNCD membranes as broadband vacuum windows at W-band frequencies

Ultra nano-crystalline diamond (UNCD) film is being studied for use as broadband vacuum windows in W-band applications. Several diamond membrane samples were obtained for testing,, ranging in thickness from 11 to 80μm. A fixture was fabricated to capture the diamond membranes between WR-10 waveguides to obtain rf transmission measurements. Ansoft HFSS was used to analyze the results. This initial investigation shows that from an electrical point of view, UNCD membranes could be used as low loss, broadband waveguide windows at W-band frequencies.