Ultrasonic catheter

An ultrasonic catheter comprising:

• a body having a longitudinal axis and a distal end;
• and
• a piezoelectric micromachined ultrasonic transducer (pMUT) array disposed within the distal end of the body, wherein the pMUT array comprises a plurality of linear phased pMUT array elements arranged on a substrate, wherein each of the linear phased pMUT array elements comprises a plurality of pMUT cells arranged in a linear array,
• wherein an insulating material is disposed over and completely encapsulates the distal end of the body, along a longitudinal shaft of the body, and over an imaging window, to provide electrical isolation and allow transmission of ultrasound signals;
• wherein one of the plurality of linear phased pMUT array elements has periodically varied spacing between the pMUT cells in a lateral direction along a longitudinal length of the one of the plurality of linear phased pMUT array elements, wherein the lateral direction is perpendicular to the longitudinal length that the one of the plurality of linear phased pMUT array elements extends;
• and
• wherein the pMUT cells of the one of the plurality of linear phased pMUT array elements are arranged in a plurality of laterally adjacent columns extending along the longitudinal length, such that at each position along the longitudinal length there are at least two pMUT cells occupying different lateral positions, and the spacing between the laterally adjacent pMUT cells at each said position varies periodically from position to position along the longitudinal length.