“…Such a calibration in the millimeter-wave range is usually performed by placing special matched loads in front of the antenna or including them in the antenna channel so that one load is at the temperature of the medium surrounding the equipment, while the other load is at the temperature of boiling nitrogen. In this case, the time of measuring the received radiation usually ranges from one-third to one-half of the duration of the entire measurement-calibration cycle, although there exist variants of calibration devices that are free of such losses of the measurement time (see, e.g., [1]). …”