A mixer comprises a substrate of a first conductivity type; at least one minority carrier injector for injecting minority carriers in the substrate in reply to a first signal applied to the at least one minority carrier injector; at least one minority carrier collector for collecting minority carriers from the substrate; and at least two substrate taps for providing a majority carrier current flow in the substrate in reply to a second signal applied to the at least two substrate taps. The at least one minority carrier injector, the at least one minority carrier collector and the at least two substrate taps are connected to the substrate such that when a majority carrier current flow is provided in the substrate, and minority carriers are injected in the substrate, the majority carrier current flow guides the minority carriers in the opposite direction of the majority carrier current flow, for collection by the minority carrier collector.