Detecting Microwave Emissions from Terrestrial Sources: A Feasibility Study

摘要

A Dicke receiver has been designed and constructed in our effort to detect the 22GHz spontaneous emission from water vapor. The receiver compares the brightness temperatures of two waveguides, one containing gaseous H2O at low pressure, the other containing dry air. Each waveguide is terminated with polished brass, which provides a low background brightness temperature, at one end and connects to the input of the receiver at the other end. The system is capable of detecting a brightness temperature difference of about 0.2 deg K. In this experiment, the radiation from water vapor produced the brightness temperature difference between source and reference of 0.28 to 0.33 deg K The experimental results proved that emission from water vapor was being detected.