An annular array transducer has its piezoelectric elements arranged in a series of concentric circles, like a target or bullseye pattern. This design allows the ultrasound beam to be electronically focused at different depths, producing better resolution throughout the image compared to a simple single-element transducer. However, because annular arrays cannot steer the beam electronically, they must be mechanically moved to create a complete image, which limits their frame rate. While annular arrays are less commonly used than linear or phased array transducers in modern practice, understanding their design helps sonography students grasp the principles of beam focusing and transducer technology.
Sonography Term