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COMMUNICATIONS APPLICATIONS OF CRYOGENIC TECHNIQUES - THE CRYOGENIC DIPLEXER.
Final rept. Mar 65-Apr 66,
RADIO CORP OF AMERICA NEW YORK COMMUNICATIONS SYSTEMS DIV
Pagination or Media Count:
Theory has been reviewed and formulated in which the resonator Q can be determined as a function of cavity temperature. It can be shown that an X-band superconducting filter can be realized with an unloaded Q of 1 million at a temperature of 4.2 K. By cooling the filter to a superfluid state of 2 K, the unloaded Q increases to 1 billion. These high-Q results imply that a 100-kilowatt transmitter can be located in frequency 50 kHz away from a receiver at 10 Gcs without producing any discernible cross or intermodulation products. This report also contains a materials study of various superconducting elements such as niobium tin, and lead. Also, the power-handling capability of a superconductor is discussed in great detail. A special task of this program was devoted to an investigation of the refrigeration cooling capacity of closed-cycle units for the various filter applications. The results of this program clearly indicate that a superconducting filter at microwave frequencies can handle vast amounts of power and give better selectivity than that commonly obtained in superheterodyne receivers.
APPROVED FOR PUBLIC RELEASE