Third order intermodulation distortion in Film Bulk Acoustic Resonators at resonance and antiresonance

This paper presents recent measurements and modeling of the third order intermodulation products of a Film Bulk Acoustic Resonator (FBAR), for a various values of frequency spacing between driving tones. The frequency dependence of voltage and current in the acoustic branch rules out a voltage-dependent nonlinearity. The results show different slopes at resonance and antiresonance, which are correctly adjusted by the model with a current dependent inductor and/or capacitor. The intermodulation distortion is found to be dependent on the frequency spacing between driving tones, indicating memory effects.