Higher bandwidth micromachined transducers mixed with biasing scheme

An ultrasound system, comprising:

• an ultrasound probe including a transducer array comprising at least one transducer element, the at least one transducer element including a first portion of capacitive micromachined ultrasound transducers (cMUTs) electrically coupled to a first bias voltage pad of the at least one transducer element, and a second portion of cMUTs electrically coupled to a second bias voltage pad of the at least one transducer element, wherein the first bias voltage pad and the second bias voltage pad are separate bias voltage pads housed within the at least one transducer element;
• a processor;
• and
• a non-transitory memory including instructions that when executed, cause the processor to:
• during a transmit mode of the at least one transducer element:
• apply a first DC bias voltage to the first portion of cMUTs of the at least one transducer element;
• apply a second DC bias voltage to the second portion of cMUTs of the at least one transducer element, the second DC bias voltage different from the first DC bias voltage, wherein a ratio between the first DC bias voltage and the second DC bias voltage is selected to maximize constructive interference while maintaining destructive interference at a level small enough to be damped by a coupling layer;
• apply an AC drive signal to the first portion of cMUTs to generate a first acoustic signal based on a first combination of the first DC bias voltage and the AC drive signal, causing membranes of the first portion of cMUTs to vibrate at a first resonance frequency defined by the first DC bias voltage;
• apply the AC drive signal to the second portion of cMUTs to generate a second acoustic signal based on a second combination of the second DC bias voltage and the AC drive signal, the second combination causing membranes of the second portion of cMUTs to vibrate at a second resonance frequency defined by the second DC bias voltage, the second resonance frequency different from the first resonance frequency by a threshold difference;
• and
• combine the first acoustic signal and the second acoustic signal to generate a higher-bandwidth signal, the higher-bandwidth signal based on constructive interference between a first transmit transfer function of the first portion of cMUTs and a second transmit transfer function of the second portion of cMUTs.