200 and 270 GHz SIS receivers for radiometric observation of stratospheric minor constituents

200 and 270 GHz radiometer/spectrometer is being developed in Communications Research Laboratory (CRL). This system is designed for the observations of height distribution of ozone, chlorine monoxide (ClO), and other minor constituents in the stratosphere. System design and present status of the system are shown. The system consists of antenna, front-end and back-end. The authors focus their discussion on the front-end of the system. The front-end includes SIS mixers and a special internal reference noise source to realize precise measurements of emission spectrum. The system including the back-end and the antenna will be completed in early 1994. The authors will start the observation with this system in the spring of 1994.<
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