Primary standard of the unit of spectral power density of noise radio-emission in the 220–300 GHz frequency range: experimental prototype
摘要
We consider the problems of metrological support of rapidly developing fields of technology, such as electronics, radio-vision, and security systems. The extension of the state standard base into a higher-frequency region (for frequencies within range 100–1000 GHz) is required for the successful technological mastering, verification, and certification of the devices and measuring instruments operating in the terahertz (millimeter) frequency band. The frequency band of the State Primary Standard for the unit of spectral power density of radio-noise radiation specified by GET 21-2021 equal to 0.002–178.3 GHz does not enable the researchers to perform precise testing and certification of currently developed devices and working high-precision measuring instruments. We present the results of development and investigation of an experimental sample of the primary standard of unit of the spectral power density of radio-noise radiation within the frequency range 220–300 GHz. The experimental sample includes a radiometer, a signal generator for the heterodyne channel, a low-temperature noise generator, a matched load, and a model attenuator. We attained the following characteristics of the experimental sample: the equivalent noise temperature of a low-temperature noise generator constitutes 103–120°K within the frequency range from 220 Hz up to 300 GHz; the sensitivity of the comparator based on the radiometer is equal to 0.86°K. The characteristics of the experimental sample are comparable with the characteristics of similar devices produced by the Radiometer Physics (Germany), world leading manufacturer. The developed experimental sample can be used for calibration of low-noise receiving and amplifying devices operating in the terahertz range, which now find extensive applications in various fields of science and technology. As an important field of application of the developed experimental sample of primary standard, we can mention the verification of radiometers used in passive radar systems. It seems also promising to use the developed radiometer (220–300 GHz) for the solution of various scientific problems encountered in the process of ground-based radio-astronomical observations in the terahertz range, in particular, in the atmospheric transparency windows at wavelengths of 1.3 and 0.8 mm, where numerous spectral lines of atoms and molecules are located.