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 electrical signal applied to the at least one minority carrier injector; at least two substrate taps located in the substrate for providing a majority carrier current density with associated electric field in the substrate in reply to a second electrical signal applied to the at least two substrate taps. The majority carrier current density's associated electric field determines the drift direction of the injected minority carriers. The mixer further comprises at least two minority carrier collectors located in the substrate, for collecting minority carriers from the substrate. Each minority carrier collector is located adjacent to one of the at least two substrate taps. A minority carrier collector destination is determined by the drift direction of the injected minority carriers, and current outputted by the minority carrier collectors based on the number of minority carriers collected at the collector destination, form an output signal of the mixer.