A4.2 - Measurement of Frequency Dependent Radiation Patterns of Ultrasonic (Wedge) Transducers
- AMA Conferences 2015
2015-05-19 - 2015-05-21
- Proceedings SENSOR 2015
- A4 - Ultrasound II
- P. Ploß, S. Rupitsch, R. Lerch - University of Erlangen-Nuremberg, Erlangen (Germany)
- 99 - 103
It is well known from theory that a transducer's radiation pattern depends on the aperture and driving frequency. Futhermore, it is widely assumed that the main lobe's orientation does not change with frequency. This work presents a novel measurement method for quickly obtaining the frequency resolved radiation pattern of ultrasonic (wedge) transducers (UT). The setup comprises a water basin, where an UT is mounted on an angle controlled tilting unit. A pulsed excitation is applied to the UT and the emitted acoustic wave is received by the same UT after being reflected at a fixed reflector plate. The received pulse is then analyzed by means of Fourier decomposition. Repetition for different angles yields a two-dimensional map angle vs. frequency. It is shown that piston-type transducer's behavior matches theoretical models very well. Wedge transducers though exhibit a frequency dependent change of the dominant radiation angle, which is not described in literature. Similar results are obtained by attaching a small plate to the wedge transducer.