With linear sequential arrays each crystal is about ______ in width and the array is up to ______ long.

With linear sequential arrays each crystal is about ______ in width and the array is up to ______ long.

• A. 0.5 wavelength; 20 cm
• B. 1.0 wavelength; 5 cm
• C. 1.5 wavelength; 8 cm
• D. 1 wavelength; 10 cm

Answer: (D)

In linear sequential arrays, each crystal is designed to be about one wavelength wide, and the overall array is kept to a practical length, around ten centimeters. This combination provides a good balance between beam control and practicality: a width near a wavelength helps produce a predictable beam with reasonable lateral resolution, while a ten-centimeter aperture keeps the probe compact and the electronics manageable. If the crystal were much narrower than a wavelength, you’d need many more elements to form the same field of view, leading to greater complexity and potential grating-lobe issues. If the crystal were wider than a wavelength, the beam shaping and focusing would change, and the probe would become bulkier with a less flexible beam pattern. A significantly longer array would also be unwieldy for typical handheld use. So, the pairing of about one wavelength in width with a total length up to around 10 cm best matches standard linear sequential array design.

In linear sequential arrays, each crystal is designed to be about one wavelength wide, and the overall array is kept to a practical length, around ten centimeters. This combination provides a good balance between beam control and practicality: a width near a wavelength helps produce a predictable beam with reasonable lateral resolution, while a ten-centimeter aperture keeps the probe compact and the electronics manageable. If the crystal were much narrower than a wavelength, you’d need many more elements to form the same field of view, leading to greater complexity and potential grating-lobe issues. If the crystal were wider than a wavelength, the beam shaping and focusing would change, and the probe would become bulkier with a less flexible beam pattern. A significantly longer array would also be unwieldy for typical handheld use. So, the pairing of about one wavelength in width with a total length up to around 10 cm best matches standard linear sequential array design.