Apparatus and method for beamforming in an ultrasonic transducer array

An ultrasound apparatus including an array of acoustic transducer elements for providing both transmit and receive functions for said ultrasound apparatus comprising:

• means for applying simultaneously a beam steering linear time delay distribution and quadratic focusing time delay distribution to said array of elements;
• and
• means for electronically changing the effective spacing of said elements between transmit and receive functions whereby the grating lobe levels of the pattern of said array are lowered, said means for changing comprising:
• means for forming adjacent groups of said elements with each group comprising at least two elements;
• and
• means for applying simultaneously a linear time delay distribution and a quadratic focusing time delay distribution to said groups of elements, the time delay to each element in a group being the same.

The method of reducing the effects of grating lobes in the pattern of an array of acoustic transducer elements comprising:

• changing electronically the effective spacing of the elements in the array between the transmit and receive modes of operation, the step of changing the effective spacing comprising:
• organizing the array into adjacent groups of elements;
• applying a beam steering time delay distribution to the array by setting a time delay for the energy associated with each element during one mode of operation;
• and
• applying the beam steering time delay distribution to the array by setting a time delay for the energy associated with each group during the remaining mode of operation, the time delay set for each element in group being the same.

An ultrasound apparatus including an array of acoustic transducer elements for providing both transmit and receive functions for said ultrasound apparatus comprising:

• means for applying a beam steering time delay distribution to said array of elements;
• and
• means for electronically changing the effective spacing of said elements between transmit and receive functions whereby the grating lobe levels of the pattern of said array are lowered, said means for changing the effective spacing comprising:
• means for forming adjacent groups of said elements with each group comprising at least two elements;
• and
• means for applying a beam steering time delay distribution to said groups of elements, the time delay to each element in a group being the same.