Abstract: Various methods and systems are provided for increasing a fractional bandwidth of an ultrasound device, for use in both low and high frequency applications. In one example, where a transducer array includes one or more transducer elements comprising a plurality of capacitive micromachined ultrasound transducers (cMUT), the fractional bandwidth may be advantageously increased by applying different bias voltages to different groupings of cMUTs within each transducer element. A ratio between the different bias voltages may be optimized to maximize the fractional bandwidth. In another example, the different bias voltages may be configured to operate a first grouping of cMUTs in a transmit mode, and a second grouping of cMUTs in a receive mode.

Abstract: Various methods and systems are provided for a microelectromechanical systems (MEMS) device. In one example, the MEMS device may include a silicon wafer with a first oxide coating, a cavity in the first oxide coating having a substantially flat floor formed of a layer of the first oxide coating and etched to a first depth prior to deposition of a masking layer, and a membrane coupled to the silicon wafer and spaced away from the substantially flat floor of the cavity by a second depth of the cavity. The second depth is a sum of the first depth and a height of a second oxide coating formed at the post regions of the MEMS device after the masking layer is removed from the post regions.

Abstract: A capacitive transducer is provided. The capacitive transducer includes a plate including a protruding center mass and a substrate with a center depression configured to accept the center mass. The capacitive transducer also includes a first electrode coupled to a non-horizontal edge surface of the center mass and a second electrode coupled to a non-horizontal edge surface of the center depression. The capacitive transducer further includes a third electrode coupled to a horizontal edge surface of the center mass and a fourth electrode coupled to a horizontal edge surface of the center depression. The plate is coupled to the substrate at least along an outer perimeter area of the plate and the substrate.

Abstract: A micromachined ultrasonic transducers with non-coplanar actuation and displacement comprising a plate with a protruding center mass, a substrate with a center depression configured to accept the center mass, a first electrode coupled to a non-horizontal edge surface of the center mass, and a second electrode coupled to a non-horizontal edge surface of the center depression. The plate may be coupled to the substrate at least along an outer perimeter area of the plate and the substrate.

Abstract: A capacitive transducer comprising a top electrode and a bottom electrode, and a sidewall between the top electrode and the bottom electrode. The sidewall is configured to separate the top electrode and the bottom electrode by a gap. There is a high contact resistance part on one or both of a bottom side of the top electrode or a top side of the bottom electrode.

Abstract: A capacitive transducer is provided. The capacitive transducer includes a plate including a protruding center mass and a substrate with a center depression configured to accept the center mass. The capacitive transducer also includes a first electrode coupled to a non-horizontal edge surface of the center mass and a second electrode coupled to a non-horizontal edge surface of the center depression. The capacitive transducer further includes a third electrode coupled to a horizontal edge surface of the center mass and a fourth electrode coupled to a horizontal edge surface of the center depression. The plate is coupled to the substrate at least along an outer perimeter area of the plate and the substrate.

Abstract: A micromachined ultrasonic transducers with non-coplanar actuation and displacement comprising a plate with a protruding center mass, a substrate with a center depression configured to accept the center mass, a first electrode coupled to a non-horizontal edge surface of the center mass, and a second electrode coupled to a non-horizontal edge surface of the center depression. The plate may be coupled to the substrate at least along an outer perimeter area of the plate and the substrate.

Abstract: A capacitive transducer comprising a top electrode and a bottom electrode, and a sidewall between the top electrode and the bottom electrode. The sidewall is configured to separate the top electrode and the bottom electrode by a gap. There is a high contact resistance part on one or both of a bottom side of the top electrode or a top side of the bottom electrode.

Abstract: A device for thermal keratoplasty, the device comprising a plurality of ultrasonic transducers for emitting ultrasound waves, wherein the ultrasound waves of at least one of the transducers is focused on a corresponding area of the cornea in order to heat these area and cause collagen shrinkage and at least one of the transducers is capable of receiving ultrasound waves for ocular imaging.