AlN Piezoelectric Nanoelectromechanical Isolator via Parametric Frequency Conversion and Amplification

We report on a novel aluminum nitride (AlN) resonant nanoelectromechanical systems (NEMS) approach to realizing an electrically tunable nonreciprocal isolator by exploiting nonlinear parametric frequency conversion and efficient mechanical amplification in a radio-frequency (RF) AlN membrane NEMS resonator. The isolator is constructed by combining frequency conversion enabled by the NEMS resonator's strong parametric effect, and tandem band-pass filtering, so that the signal can be transmitted or blocked according to its propagation direction and frequency. In the band of the isolator that is set by the NEMS resonance, it exhibits up to ~60dB signal isolation between measured S21 and S12 transmission. Further, the isolation band frequency and width can be tuned via a dc polarization voltage.