In a convex array, the crystals are typically about how wide?

• A. 1/4 wavelength
• B. 1/2 wavelength
• C. 1 wavelength
• D. 2 wavelengths

Answer: (C)

The size of each crystal relative to the wavelength sets the aperture of the transducer, which directly shapes the ultrasound beam. In a convex array, using crystals about one wavelength wide provides a practical aperture that yields a reasonably narrow, steerable beam across the curved surface while keeping manufacturing feasible. If the elements were much narrower, the aperture would be too small and the beam would be wide, reducing lateral resolution. If they were much wider, the aperture would grow, potentially complicating the design and increasing sidelobe or grating-lobe issues unless the spacing and geometry are carefully managed. So, about one wavelength wide is a typical, balanced choice for convex arrays.