Electroacoustic transducer array

An electroacoustic transducer array comprising:

• one or more active elements;
• an acoustic coupling layer arranged to acoustically couple, in use, at least some of the one or more active elements to a liquid transmission medium, wherein the acoustic coupling layer comprises an acoustic meta-material having pores, voids and/or spacings;
• at least one of the one or more active elements is spaced from the acoustic coupling layer by a cavity arranged between the at least some of the one or more active elements and the acoustic coupling layer, wherein the cavity is in fluid communication with the liquid transmission medium via the pores, voids, and/or spacings, and wherein the cavity contains part of the liquid transmission medium, in use;
• and
• an array housing arranged to house the one or more active elements and wherein the acoustic coupling layer is arranged to extend across at least a part of a surface of the array housing.

An electroacoustic transducer array for use in a liquid transmission medium, comprising:

• one or more active elements;
• an acoustic coupling layer arranged to acoustically couple, in use, the one or more active elements to a liquid transmission medium, wherein the acoustic coupling layer comprises an acoustic meta-material having pores, voids, and/or spacings;
• the one or more active elements spaced from the acoustic coupling layer by a cavity arranged between at least one of the one or more active elements and the acoustic coupling layer, wherein the cavity is in fluid communication with the liquid transmission medium via the pores, voids, and/or spacings, and wherein the cavity contains part of the liquid transmission medium, in use;
• and
• wherein the transmission medium provides a fluid reservoir to the cavity.