FIG. 7.

Linear array aperture geometry and directivity. (a) Ultrasound imaging linear array configuration. θ is the cross-propagation angle, p the pitch of the linear transducer array, x₁ the first element of the active aperture (blue elements), x_b the element along the aperture, and x_n an arbitrary element along the array. d_tx is the distance from the planar wavefront to a point along the bisector, and d_rx is the return distance to the array. Silent elements are labelled in orange. (b) Directivity of an individual element of the linear transducer array (p = 0.1 mm, f = 15.6 MHz). The red dotted line indicates the – 3 dB acoustic pressure level.