An ultrasonic transducer comprising: a piezoelectric element having a characteristic acoustic impedance; a front acoustic impedance converter coupled to said piezoelectric element , wherein said front acoustic impedance converter comprises: a front polymer layer having a substantially uniform thickness t p1 coupled to said piezoelectric element ; and a front metal layer for transmitting acoustic energy between said front polymer layer and a propagation medium having a characteristic acoustic impedance, said front metal layer having a substantially uniform thickness t m1 and being coupled to said front polymer layer , wherein said characteristic acoustic impedance of said propagation medium is lower than said characteristic acoustic impedance of said piezoelectric element, and wherein said front acoustic impedance converter has an effective characteristic acoustic impedance Z c between said piezoelectric element and said propagation medium characteristic acoustic impedances, characterized in that said front polymer layer is arranged intermediate said piezoelectric element and said front metal layer , so that the front metal layer is disposed on the polymer layer ; and in that the front polymer layer has parallel opposing planar first surface and second surface , and metal layer has parallel opposing planar first surface and second surface , wherein the first surface of the metal layer is bonded or otherwise coupled to the second surface of polymer layer . a piezoelectric element having a characteristic acoustic impedance; a front acoustic impedance converter coupled to said piezoelectric element , wherein said front acoustic impedance converter comprises: a front polymer layer having a substantially uniform thickness t p1 coupled to said piezoelectric element ; and a front metal layer for transmitting acoustic energy between said front polymer layer and a propagation medium having a characteristic acoustic impedance, said front metal layer having a substantially uniform thickness t m1 and being coupled to said front polymer layer , a front polymer layer having a substantially uniform thickness t p1 coupled to said piezoelectric element ; and a front metal layer for transmitting acoustic energy between said front polymer layer and a propagation medium having a characteristic acoustic impedance, said front metal layer having a substantially uniform thickness t m1 and being coupled to said front polymer layer , wherein said characteristic acoustic impedance of said propagation medium is lower than said characteristic acoustic impedance of said piezoelectric element, and wherein said front acoustic impedance converter has an effective characteristic acoustic impedance Z c between said piezoelectric element and said propagation medium characteristic acoustic impedances, characterized in that said front polymer layer is arranged intermediate said piezoelectric element and said front metal layer , so that the front metal layer is disposed on the polymer layer ; and in that the front polymer layer has parallel opposing planar first surface and second surface , and metal layer has parallel opposing planar first surface and second surface , wherein the first surface of the metal layer is bonded or otherwise coupled to the second surface of polymer layer . <EOS>