Microwave switch based on S-N transition in high-Tc superconducting film

An effective microwave switch using the transition from the superconducting state to the normal slate (S-N transition) is presented. The main problem in designing an S-N switch arises from the low surface resistance of high-T-C superconducting mms in the N-state, which makes it difficult to obtain a low return loss. The authors have found a way to overcome this difficulty by including transformation circuits as an essential part of the S-N switch.