A double-balanced wide band RF mixer includes a first bifilar balun transformer coupling a high level source of RF signal to the primary windings of a pair of trifilar balun transformers. The two output windings of each trifilar transformer are connected in series with the drain-source circuits of a pair of FET transistors which are alternately activated by a symmetric local oscillator signal. An IF signal with reduced second order products of the RF signal is developed between the output windings of the two trifilar balun transformers.