On Chip Noise Cancellation for Piezoelectric Micromachined Ultrasound Transducers

A novel method to cancel temporal electro-magnetic (EM) noise for piezoelectric micromachined ultrasound transducers (PMUT) is presented. When in operation, the PMUT transducer is exposed to environmental EM noise that can severely impact image quality. Since these EM bursts can be temporal, they cannot be effectively removed using averaging. By leveraging a dummy row of electrodes without cavities, a cancellation mechanism is shown that can remove temporal EM noise from the received signal. Using this approach, temporal EM noise can be reduced by up to 20 dB and reductions in harmonic components can also be seen across the frequency spectrum.