Broad band microwave spectroscopy of cooled monolithic circuits

The use of a high-T/sub c/ Josephson junction for broadband spectrum analysis is discussed. A YBCO grain boundary junction was coupled to a YBCO/SiO/Pb microstrip resonator and spectra were taken in the frequency range 0-300 GHz and over temperatures from 4-70 K. Values of microstrip attenuation (>0.003 dB/ mu m) and phase velocity ( approximately 0.17 c/sub 0/, where c/sub 0/ is the speed of light in vacuum) were extracted. In particular, a signal dispersion of less than 3% over the range 80-220 GHz was observed.<
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