Near Field Distance of Flat Transducers in Water | ||||
Frequency | Element Diameter | N | Focal Length (PTF)** | |
Min | Max | |||
(MHz) | (inches) | (inches) | (inches) | (inches) |
0.5 | 1.50 | 4.757 | 2.15 | 3.80 |
1.125 | 2.661 | 1.50 | 2.10 | |
1.00 | 2.095 | 1.25 | 1.65 | |
0.75 | 1.164 | 0.78 | 0.93 | |
1.0 | 1.50 | 9.559 | 2.50 | 7.65 |
1.125 | 5.366 | 1.90 | 4.30 | |
1.00 | 4.235 | 1.625 | 3.38 | |
0.75 | 2.372 | 1.00 | 1.90 | |
0.50 | 1.043 | 0.60 | 0.80 | |
2.25 | 1.50 | 21.534 | 2.70 | 14.50 |
1.125 | 12.099 | 2.15 | 9.50 | |
1.00 | 9.554 | 1.875 | 7.60 | |
0.75 | 5.364 | 1.00 | 4.30 | |
0.50 | 2.374 | 0.80 | 1.90 | |
0.375 | 1.329 | 0.50 | 1.06 | |
0.25 | 0.584 | 0.35 | 0.45 | |
3.5 | 1.00 | 14.868 | 1.95 | 11.5 |
0.75 | 8.350 | 1.00 | 6.65 | |
0.50 | 3.699 | 0.83 | 2.95 | |
0.375 | 2.073 | 0.60 | 1.65 | |
0.25 | 0.914 | 0.385 | 0.70 | |
5.0 | 1.00 | 21.243 | 1.95 | 14.40‡ |
0.75 | 11.932 | 1.00 | 9.50 | |
0.50 | 5.287 | 0.75 | 4.20 | |
0.375 | 2.965 | 0.60 | 2.35 | |
0.25 | 1.309 | 0.43 | 1.00 | |
7.5 | 0.75 | 17.900 | 1.00 | 12.75‡ |
0.50 | 7.933 | 0.75 | 6.30‡ | |
10 | 1.00 | 42.490 | 2.00 | 20.00‡ |
0.75 | 23.868 | 1.00 | 15.375‡ | |
0.50 | 10.579 | 0.75 | 8.40‡ | |
0.375 | 5.934 | 0.60 | 4.75‡ | |
0.25 | 2.622 | 0.46 | 2.10 | |
15 | 0.50 | 15.870 | 0.75 | 11.75‡ |
0.375 | 8.902 | 0.60 | 7.10‡ | |
0.25 | 3.935 | 0.50 | 3.15‡ | |
20 | 0.25 | 5.247 | 0.50 | 4.20‡ |
0.125 | 1.290 | 0.25 | 1.00‡ | |
25 | 0.25 | 6.559 | 0.50 | 5.25‡ |
** Olympus Immersion Transducers with straight connectors can be focused between the Minimum and Maximum Point Target Focal (PTF) distance limits listed above. Please consult Olympus before ordering a transducer focused outside these limits.
‡ Consideration should be given to attenuation effects which increase linearity and with the square of frequency and the square of bandwidth. In applications where long water paths are required the effects of frequency dependent attenuation should be checked per ASTM E 1065 Annex A7. It is advisable to consider the effects of frequency dependent attenuation if the focal distance equals or exceeds the following values:
