  We present a design for a superconducting, on-chip circulator composed of
dynamically modulated transfer switches and delays. Design goals are set for
the multiplexed readout of superconducting qubits. Simulations of the device
show that it allows for low-loss circulation (insertion loss < 0.35 dB and
isolation >20 dB) over an instantaneous bandwidth of 2.3 GHz. As the device is
estimated to be linear for input powers up to -65 dBm, this design improves on
the bandwidth and power-handling of previous superconducting circulators by
over a factor of 50, making it ideal for integration with broadband quantum
limited amplifiers.
