Peak sensitivity of W-band radiometers

W-band radiometers occupy an important role in astrophysical observations and passive remote sensing. The most important characteristics of W-band radiometers, which determine their application possibilities, are temperature sensitivity and sensitivity of the spectral power of the radio signal at the receiving antenna. In this regard, an analysis of the achievable sensitivity limits for W-band radiometers at the current level of scientific and technological development was carried out. The achievable maximum temperature sensitivity of modern W-band radiometers reaches 65 μК, and the spectral power sensitivity reaches 22 μJy. The most sensitive W-band radiometers currently available (Planck space observatory) have a temperature sensitivity of about 100 μК and a spectral power sensitivity of about 10 mJy. Thus, W-band radiometers have great potential for increasing sensitivity, which opens up great opportunities for their use in promising applied (development of orientation and navigation systems based on the CMB) and fundamental (measurement of CMB polarization, observation of cold matter in the Universe) tasks.