3mm band measure radiometer/receiver system

A 3-mm band radiometer/receiver system is presented in this paper, which is used to measure characteristics of gaseous mass. The equipment works on double mode, active and passive, in different time. In active mode, it works as a narrow-band and high sensitive receiver that measures insertion loss of gaseous mass. And in passive mode, it is a millimeter wave radiometer that measures emissive characteristic of gaseous mass. The system principle and measuring method are discussed in detail in this paper.