The ultra-low absorption investigation in dielectrics and atmosphere within 45-200 GHz frequency band

The new generation set of 45-200 GHz band for the investigation of dielectric absorption, including the atmosphere is created. Special attention is paid both to the investigation of ultralow absorption in the modern high-quality dielectrics, including thin films and to the atmospheric absorption, including the lines of oxygen and water absorption. It was found that Si and diamond output windows for the megawatt microwave gyrotrons have the essential absorption in thin, /spl Lt//spl lambda/, surface layer, leading to surface discharges. Practically all rolled film materials have the distinct anisotropy of dielectric parameters, which also depend upon the producer. The results of atmospheric absorption measurement have been compared with theoretical models.