For producing a low-power, low-phase noise oscillating signal using a self-injection locking oscillator, examples include: producing, using an oscillator, a signal having a base frequency component and an Nth harmonic component, in which N is a selected integer and N>1; filtering the signal through a bandpass filter with Q factor ≥5, the filter configured to pass the Nth harmonic component as a filtered Nth harmonic component; and injecting the filtered Nth harmonic component into the oscillator to self-injection lock the base frequency of the signal.