Fig. 2: Characteristics of a single element.

a Transmit efficiency and b receive sensitivity as a function of frequency in water. c Transmit efficiency at 8.93 MHz as a function of location at transducer surface measured in water. d Magnitude and e phase of the electrical impedance as a function of frequency for the condition in which the active surface area of the transducer is in contact with air or oil. Experimental results are indicated by solid lines. Modeled results use dotted lines.