Microwave Signal Limiters and Commutators Based on Superconducting Films

An essential property of the superconducting film is S-N transition which can be induced by ac or dc current and exhibits in the large change of the film surface resistance. The S-N transition is used for performing microwave signal limiters or commutators with a high operational speed. The theory and practical realization of such devices have been developed. Some elements of CAD for HTSC microstrip lines has been elaborated on the base of the phenomenological model of the HTSC microwave surface resistance. The signal limiter and commutator are contributions to the HTSC microwave technique along with such elements as stripline, resonator, filter, patch antenna. The possibility of combining all these elements into cryogenic microwave integrated circuits is discussed.