Instrumental complex and the results of precise measurements of millimeter- and submillimeter-wave propagation in condensed media and the atmosphere

Abstract

We describe an instrumental complex based on high-Q open Fabry-Perot resonators for the frequency band 36-370 GHz and present original measurement techniques and the latest results of measuring (i) refractive indices and losses of modern high-quality dielectrics for high-power electronics (with prognosis for up to the terahertz band) and general-purpose dielectrics including films, (ii) reflectivities of both antenna reflectors of cryogenic-receiver radiotelescopes and the so-called "hot" antennas for future Mercurian missions, and (iii) the atmospheric absorption for the development of high-precision wave-propagation models including the continuum absorption. The instrumentation and the measurement techniques are intended for studying condensed-media parameters at temperatures 80-900 K and atmospheric parameters at temperatures from −40 • C to +60 • C and humidities from 0 to 80%.

Precision Characterization of Gyrotron Window Materials

“…Additional, high-quality, room temperature measurements were obtained on samples of CVD diamond, sapphire, and quartz. Comparison of these results with those from the Microwave Diagnostic Laboratory of the Institute of Applied Physics of the Russian Academy of Sciences (3) provided confirmation of our data's accuracy. Regrettably, we were not able to measure samples of other wide-gap semiconductors as originally proposed.…”

Measurement of Dielectric Properties for Low-Loss Materials at Millimeter Wavelengths

“…For comparison purposes, the data available on very low-loss materials at frequencies above 100 GHz has come primarily from two laboratories, the Institut für Materialforschung (IMF I) at Forschungzentrum Karlsruhe [11][12][13] and the Institute of Applied Physics (IAP) of the Russian Academy of Sciences [14,15]. Table 3 shows a comparison of our loss tangent values for CVD diamond, sapphire, and quartz, with data from those laboratories.…”

Dielectric parameters of the modern low-loss ceramics in the microwave, millimeter, and submillimeter ranges.

“…A more detailed description of the measurement techniques is presented in [4][5][6]. And the measurement setup and its specifications are presented in [7,8].…”