Development and characterization of a sparse ellipsoidal 256 element array for volumetric ultrasound imaging

Sparse 2D matrix arrays represent an alternative to fully populated arrays for a more efficient use of available electronic channels. While individually driving the elements of fully populated matrix arrays requires electronics with thousands of elements, the requirements to the multichannel electronics can be dramatically reduced with sparse arrays. In our work, we developed and characterized a sparse 2D array with a spiral element pattern. The array consists of 256 elements in a 513 µm pitched matrix. An elliptical geometry was chosen in view of a later use in volumetric transperineal imaging. The array was processed on a conductive backing. An average centre frequency of 4,2 MHz (1,4 MHz −6 dB bandwidth) was measured. A wire phantom was used for assessment of the imaging performance. When excited with a single plane wave (0°), the FWHM ranged between 750 µm and 1100 µm (in x- and y- direction respectively).