Dynamical isolation of a cryogenic processor

A method of operation of a multiplexer microwave circuit, the multiplexer microwave circuit comprising a plurality of microwave paths, each microwave path travelling between an input and a respective one of a plurality of outputs, wherein each microwave path comprises at least one broadband switch, and a plurality of addressing lines, each addressing line communicatively coupled to one or more broadband switches, the method comprising:

• modulating an addressing line communicatively coupled to the at least one broadband switch on a microwave path in the plurality of microwave paths to set the at least one broadband switch to a passing state;
• and
• applying a signal to the input, the signal travelling to one of the outputs along the microwave path where the at least one broadband switch is in a passing state.