Abstract: There is provided an apodizing wedge structure for a LIPUS treatment head. The LIPUS treatment head includes a low-volume fraction piezoelectric composite disc. The apodizing wedge structure includes an annular body for contacting a surface of the piezoelectric disc, the annular body including an inner perimeter having an inner thickness and an outer perimeter having an outer thickness. The annular body includes an inclined surface forming a continuous slope extending from the inner perimeter to the outer perimeter, the inner thickness being smaller than the outer thickness. The apodizing wedge is configured to change an apparent thickness of the piezoelectric disc with respect to resonant properties of the piezoelectric disc when the apodizing wedge structure is in acoustic communication with the piezoelectric disc, thereby allowing the LIPUS treatment head to generate a uniform near field. LIPUS treatment heads and ultrasonic transducers including such an apodizing wedge structure are also provided.

Abstract: There is provided an ultrasonic transducer having a sample-contacting portion and a back portion, the back portion being opposed to the sample contacting portion. The transducer includes a piezoelectric material configured to be in acoustic communication with a sample and a backing structure in acoustic communication with the piezoelectric material. The backing structure is configured to reflect acoustic energy towards the sample-contacting portion and away from the back portion of the ultrasonic transducer. The backing structure includes a low acoustic impedance layer and a high acoustic impedance layer. The transducer may also include a second dual layer de-matching backing. The second dual layer de-matching backing includes a second low acoustic impedance layer and a second high acoustic impedance layer.

Abstract: There are provided an ultrasonic transducer and methods for designing and manufacturing the same. The ultrasonic transducer includes a piezoelectric composite layer configured to be in acoustic communication with a sample and having at least partially decoupled acoustic impedance and electrical impedance properties. The piezoelectric composite layer includes an array of spaced-apart piezoelectric regions, each being made from a piezoelectric material, a filler material positioned between adjacent spaced-apart piezoelectric regions, the filler material comprising a polymer matrix and a non-piezoelectric material in contact with the polymer matrix.

Abstract: There are provided an ultrasonic transducer and methods for designing and manufacturing the same. The ultrasonic transducer includes a piezoelectric composite layer configured to be in acoustic communication with a sample and having at least partially decoupled acoustic impedance and electrical impedance properties. The piezoelectric composite layer includes an array of spaced-apart piezoelectric regions, each being made from a piezoelectric material, a filler material positioned between adjacent spaced-apart piezoelectric regions, the filler material comprising a polymer matrix and a non-piezoelectric material in contact with the polymer matrix.

Abstract: There are provided an ultrasonic transducer and methods for designing and manufacturing the same. The ultrasonic transducer includes a piezoelectric composite layer configured to be in acoustic communication with a sample and having at least partially decoupled acoustic impedance and electrical impedance properties. The piezoelectric composite layer includes an array of spaced-apart piezoelectric regions, each being made from a piezoelectric material, a filler material positioned between adjacent spaced-apart piezoelectric regions, the filler material comprising a polymer matrix and a non-piezoelectric material in contact with the polymer matrix.