A sub-harmonic electronic mixer has at least one field effect transistor (FET) having a gate, source, and drain; and a useful signal input at a useful frequency; and a local oscillator input. The input receives the oscillator signal at a frequency being an integral fraction of the useful frequency, plus or minus a mixing frequency to provide a signal output. A gate of the FET and/or the drain and/or the source receives the useful signal to generate a gate-source voltage and/or a drain-source voltage whereby the gate receives the local oscillator signal to generate a gate-source voltage, and the drain or a source receives the local oscillator signal to generate a drain-source voltage. A phase shift is introduced between the signal received at the gate and the signal received at the drain or source of the FET.