Variable-size elements in 2D sparse arrays for 3D medical ultrasound

The sparse array technique is an excellent approach to tackle the connection difficulties due to the huge number of elements of 2D matrix arrays. However, the reduction of the element number leads to significant performance reduction, especially in terms of energy loss. An efficient alternative to increase the array sensitivity is using elements wider than λ/2 while non-grid positioning strategies are adopted. To further decrease the unwanted lobes of the array beam, the variable-size elements array is proposed. This new configuration, combining the randomness of elements position and of their size, leads to excellent beam patterns. In addition, the main lobe width can be controlled to change the array spatial resolution.