Rectangular sparse array with equal transmit-receive element counts for 3D ultrasound imaging

2-D arrays which enable dynamic focusing and steering capability in the 3-D space offer clinical benefits over 1-D arrays in volumetric imaging, but also present challenges associated with massive element counts. Various sparse array designs have been proposed to drive 2-D arrays at reduced cost, while minimizing degradation in beam patterns by effectively suppressing grating and side lobes. Deterministic sparse arrays, which produce layouts based on equations or pre-determined patterns with radial, spiral, or rectangular shapes, are designed to have different density for both transmit and receive arrays to suppress grating lobes. As a result, for most designs, a pair of designed layouts requires an unequal number of active elements. This means that customized systems are needed to operate such arrays since ultrasound imaging systems often come with an equal number of transmit and receive channels. Here, a new deterministic design method is presented that produces a pair of layouts with equal element counts. Our method is based on rectangular sparse arrays where two 1-D sparse patterns are applied orthogonally to x- and y-axis. Specifically, one 1-D pattern is first applied to the x-axis of the transmit array while the other 1-D pattern is applied to the y-axis. For the receive array, the later 1-D pattern is applied to the x-axis, and the former to the y-axis. Two arrays based on 64 × 64 and 64 × 32 footprints were designed, and their performance was assessed via a series of simulations and compared to previous methods and fully sampled arrays.