Ultrasound selectable frequency response system and method for multi-layer transducers

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer;
• (b) transferring energy in a second layer;
• (c) altering a first signal associated with the first layer relative to a second signal associated with the second layer, the alteration a function of a difference in acoustic transfer characteristics of the first and second layers;
• and
• (d) determining a resonance frequency of the element as a function of (c) with first and second separate receive beamformation channels for the first and second layers, respectively.

An ultrasound transducer element of a transducer array for imaging at one or more frequencies, the transducer element comprising:

• a first layer;
• and
• a second layer stacked with the first layer along a range dimension;
• and
• a matching layer adjacent the second layer, the matching layer varying in an impedance characteristic along one dimension;
• and
• wherein the matching layer matches a lower frequency at an edge portion along the elevation dimension and matches a higher frequency at a center portion, the higher frequency a harmonic of the lower frequency.

An ultrasound transducer element of a transducer array for imaging at one or more frequencies, the transducer element comprising:

• a first layer;
• and
• a second layer stacked with the first layer along a range dimension;
• and a matching layer adjacent the second layer, the matching layer varying in an impedance characteristic along one dimension;
• and
• wherein the matching layer comprises at least two different materials, a density of the first material greater at edge portions than at a center portion of the matching layer and a density of the second material greater at the center portion than at the edge portions of the matching layer.

An ultrasound transducer element of a transducer array for imaging at one or more frequencies, the transducer element comprising:

• a first layer;
• and
• a second layer stacked with the first layer along a range dimension;
• and a matching layer adjacent the second layer, the matching layer varying in an impedance characteristic along one dimension;
• and
• wherein the matching layer is patterned along an elevation dimension, the patterning providing one of apertures, divots and indentions.

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer;
• (b) transferring energy in a second layer;
• (c) increasing a bandwidth of the transducer element as a function of an impedance variation of a matching layer along one dimension, the matching layer adjacent the second layer;
• (d) matching an impedance for a lower frequency at an edge of the element;
• and
• (e) matching an impedance for a higher frequency at a center of the element, the higher frequency being a harmonic of the lower frequency.

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer;
• (b) transferring energy in a second layer;
• (c) increasing a bandwidth of the transducer element as a function of an impedance variation of a matching layer along one dimension, the matching layer adjacent the second layer;
• wherein (c) comprises varying a density of a first matching layer material relative the density of a second matching layer material, the density of the first matching layer material being greater at edge portions of the element along an elevation dimension.

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer;
• (b) transferring energy in a second layer;
• (c) increasing a bandwidth of the transducer element as a function of an impedance variation of a matching layer along one dimension, the matching layer adjacent the second layer;
• wherein (c) comprises patterning the matching layer, the patterning providing one of apertures, divots and indentions.

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer;
• (b) transferring energy in a second layer;
• (c) increasing a bandwidth of the transducer element as a function of an impedance variation of a matching layer along one dimension, the matching layer adjacent the second layer;
• wherein the first layer comprises a solid piezoelectric material and the second layer comprises a peizo-composite material;
• and further comprising:
• (d) altering a first signal associated with the first layer relative to a second signal associated with the second layer, the alteration a function of a difference in acoustic transfer characteristics of the first and second layers.

An ultrasound transducer multiplexer for connecting a bi-layer transducer element, the multiplexer comprising:

• a first switch connectable between a first path and a first electrode of the bi-layer transducer element;
• a second switch connectable between a second path and the first electrode;
• and
• a third switch connectable between the second path and a second electrode of the bi-layer transducer element.

A method for operating a bi-layer transducer element, the method comprising:

• (a) transferring energy in a first layer of the bi-layer transducer element;
• (b) transferring energy in a second layer of the bi-layer transducer element;
• and
• (c) selecting connections between at least two electrodes and two paths for (a) and (b), a frequency of operation responsive to the selection.