Table 1.

Characteristics of the ultrasound transducers

Center frequency, MHz	−6 dB bandwidth, MHz	−20 dB bandwidth, MHz	Aperture diameter, mm	Panametrics part no	Type
2.25	1.4–2.8	0.7–3.5	13	V-306-SU	Flat
5.0	3.1–6.7	1.2–8.1	13	V-309-SU	Flat
10.0	6.3–12.1	2.5–14.5	13	V-311-SU	Flat
2.5	1.8–3.4	1.5–4.6	13	Krautkramer, Gamma Series	Focused
5.0	3.4–6.8	1.9–8.5	13	V-309-SU	Focused