Abstract: For ultrasound imaging using a matrix transducer, interconnects or switches are provided to allow sub-arrays forming a 1D array, such as with sub-arrays one element wide with the maximum number of elements in elevation. Where groups are used to limit the switches and available system channels per group, an extra switch may connect between elements of different groups through a group output to extend a sub-array across groups. To further limit the number of switches, the group may be sub-divided where different combinations of sub-groups are connectable with different combinations of the system channels for the group.