A frequency converter uses first and second complementary symmetry FET's to perform respective oscillator and mixer functions. The first and second FET's are arranged with respective conduction channels connected in series. The oscillator function is performed by the first FET via feedback provided between its source or drain electrode to its gate electrode. The mixer function is provided by the second FET via an input circuit coupling an input signal to its gate electrode. Sum and difference beat frequencies are available at the circuit node interconnecting the conduction channels of the first and second FET's.