Domino circuit and related architectures and methods for carrier aggregation. In some embodiments, a Domino circuit can include first and second signal paths for respective first and second frequency bands, and each signal path can be configured to present an approximately zero impedance to a signal in the other frequency band. The Domino circuit can further include a coupling circuit that couples the first and second signal paths, and configured such that the approximately zero impedance presented by the signal path to the signal in the other frequency band results in the signal in the other frequency band being substantially excluded from the signal path.