A microwave radiometer for deep noninvasive diagnostics of thermal fields inside a biological object

A microwave radiometer for a wavelength of 10.5 cm with a frequency band of received signals of 200 MHz is described. It allows one to perform remote noninvasive temperature measurements deep in a biological object. The use of a modified null–reception method as the basis of the instrument operation made it possible to reduce the influence of the reflectance at the location of the contact between an applicator antenna and a body on the measurement accuracy and increase the dynamic characteristics during mapping of a biological object. At a storage signal time of 1 s, the measurement accuracy was 0.047 K. The output–signal changes were within 0.1 K when the reflectance was varied from 0.1 to 0.5.