The active element is typically made of piezoelectric crystals or newer materials for higher sensitivity and bandwidth. The lens or matching layer is often composed of acoustic polymers to optimize impedance matching between the transducer and tissue.

Operates at specific frequencies, with higher frequencies offering better resolution but shallower penetration. Multi-frequency probes support adjustable frequencies for different imaging depths.

• Linear array: Flat footprint, high near-field resolution (e.g., vascular imaging)
• Curved array (convex): Wider field of view for deep abdominal scans
• Phased array: Small footprint with steering capability (e.g., cardiac imaging)

The physical size and shape vary by application (e.g., small footprints for interventional or pediatric use).

A backing layer absorbs backward-directed vibrations to shorten pulse duration, improving axial resolution.

Reduces acoustic impedance mismatch between the transducer and tissue, enhancing energy transmission.

Designed to minimize heat generation (meeting FDA/IEC limits for surface temperature rise). Electrically insulated to protect patients and operators.

Modern probes support dynamic focusing, electronic steering, and multi-line acquisition for real-time imaging.

Encased in robust materials (e.g., plastic, metal) resistant to wear and chemical disinfectants. Some probes are waterproof for intraoperative or endoscopic use.

3D/4D probes: Incorporate mechanical or matrix arrays for volumetric imaging. Intracavitary probes: Miniaturized designs for transvaginal/transrectal applications.