**41**, 3, pp. 599–612, 2016

**10.1515/aoa-2016-0058**

### Research and Modeling of Mechanical Crosstalk in Linear Arrays of Ultrasonic Transducers

*in vivo*. The crosstalk phenomenon occurs during the operation of transducers in which electrical voltages and mechanical vibrations are transmitted to adjacent components. As a result of such additional excitation of the transducers in the array, the directivity characteristics of the aperture used changes, and consequently there is interference with proper operation of a given array and the emergence of distortions in the obtained ultrasound image that reduce its quality. This paper studies the manner of propagation of mechanical crosstalk in the designed model of a linear array of ultrasonic transducers on the basis of unwanted signals, which appeared on elementary piezoelectric transducers when power is supplied to the selected transducer in the array. The universal model of linear array of ultrasonic transducers, which has been developed, allowed the simulation of mechanical crosstalk, taking into account the cross-coupling phenomenon in all of its structure with the use of finite elements method (FEM) implemented in COMSOL Multiphysics software. The analysis of crosstalk signals showed that they consist of aggregated pulses propagating with different speeds and frequencies. This signifies the formation of different vibration modes transmitted simultaneously via different paths. The paper is an original approach which enables to identify different vibration modes and estimate their participation in the crosstalk signal and their ways of propagation. Conclusions from the research allow predicting specific design changes which are significant due to the minimization of mechanical crosstalk in linear arrays of ultrasonic transducers.

**Keywords**: mechanical crosstalk; ultrasonic transducer array; FEM modeling; COMSOL Multiphysics.

**Full Text:**PDF

#### References

Abboud N.N., Wojcik G.L., Vaughan D.K., Mould J., Powell D.J., Nikodym L. (1998), Finite element modeling for ultrasonic transducers, Medical Imaging: Ultrasonic Transducer Engineering, Proc. SPIE, 3341, 19–42.

Acevedo P., García-Nocetti D.F., Recuero M., Sánchez I. (2015), Simulation of the crosstalk effect of a piezoelectric matrix array oscillating in the lateral mode, International Journal of Physical Sciences, 3, 2, 021–031.

Ballandras S., Edoa P.F., Langrognet F., Steichen W., Pierre G. (2000), Prediction and measurement of cross-talk effects in a periodic linear array built using ultrasound micromachining, Proceedings of the IEEE Ultrasonics Symposium, San Juan, Puerto Rico, 1139–1142.

Bayram B., Yaralioglu G.G., Kupnik M., Khuri-Yakub B.T., Ginzton E.L. (2006), Acoustic crosstalk reduction method for CMUT arrays, IEEE Ultrasonics Symposium, 590–593.

Berg S., Rønnekleiv A. (2006), Reducing fluid coupled crosstalk between membranes in CMUT arrays by introducing a lossy top layer, 2006 IEEE Ultrasonic Symposium, 594–597.

Bertora F. (2007), Ultrasound transducers, [in:] Physics for Medical Imaging Applications, Ch. 1, Y. Lemoigne et al. [Eds.], Springer, 111–121.

Blackstock D.T. (2000), Fundamentals of Physical Acoustics, John Wiley and Sons, Inc., 568 pages.

Bybi A., Assaad J., Hladky-Hennion A.-Ch., Benmeddour F., Grondel S., Rivart F. (2013), Numerical study of the cross-talk effects in acoustical transducer arrays and correction, Proceedings of Meetings on Acoustics, 19 (030049), 8 pages.

Celmer M., Opielinski K.J. (2014), Crosstalk effects in multielement ultrasonic transducer arrays, European Acoustics Association Proceedings of the 7th Forum Acusticum, Krakow, Poland, 5 pages.

Celmer M., Opieliński K.J. (2015), Study of Crosstalk in Linear Ultrasonic Transducer Arrays, Acta Acustica united with Acustica, 101, 46–54.

Celmer M., Opieliński K.J. (2015), Research on crosstalk in commercial ultrasonography arrays [in Polish], [in:] Progress of Acoustics, K.J. Opieliński [Ed.], Wrocław Division of Polish Acoustical Society, Wrocław, 63–74.

COMSOL (2012), Comsol Multiphysics User’s Guide, ver. 4.3, COMSOL Multiphisicsr, www.comsol.com, 1292 pages.

COMSOL (2013), Acoustic Module User’s Guide, ver.4.3b, COMSOL Multiphisicsr, www.comsol.com, 444 pages.

Dominguez I.S., Contla P.A., Hernandez E.M., von Kruger M.A. (2011), Crosstalk effects caused by the geometry of piezoelectric elements in matrix ultrasonic transducers, Brazilian Journal of Biomedical Engineering, 27, 90–97.

Domínguez I.S., Contla P.A. (2013), Construction and Characterization of an Ultrasonic Array Using Different Backing Materials to Evaluate Crosstalk, Journal of Materials Science and Engineering B, 3, 8, 493–497.

Drinkwater B.W., Wilcox P.D. (2006), Ultrasonic arrays for nondestructive evaluation: A review, NDT & E International, 39, 525–541.

Eames M.D.C., Hossack J.A. (2008), Fabrication and evaluation of fully-sampled, twodimensional transducer array for “Sonic Window” imaging system, Ultrasonics, 48, 376–383.

Gudra T., Opielinski K.J. (2006), The ultrasonic probe for the investigating of internal object structure by ultrasound transmission tomography, Ultrasonics, 44, e679–e683.

Guess F., Oakley’ C.C., Douglas S.J., Morgan R.D. (1995), Cross-talk paths in array transducers, Proceedings of the IEEE Ultrasonics Symposium, 1279–1282.

Guo N.Q., Cawley P. (1990), Three dimensional analysis of the vibration characteristics of piezoelectric discs, Review of Progress in Quantitative Nondestructive Evaluation, 9, 789–794.

Gutierrez M.I., Vera A., Leija L. (2010), Finite element modeling of acoustic field of physiotherapy ultrasonic transducers and the comparison with measurements, [in:] Pan American Health Care Exchange (PAHCE), 76–80.

Khuri-Yakub B.T., Oralkan Ö. (2011), Capacitive micromachined ultrasonic transducers for medical imaging and therapy, Journal of Micromechanics and Microengineering, 21, 5, 54004–54014.

Kino G., Baer R. (1983), Theory for cross-coupling, 1983 IEEE Ultrasonics Symposium, 2, 1013–1019.

Lamberti N. (1999), Radiation pattern distortion caused by the interelement coupling in linear array transducer, IEEE Ultrasonics Symposium, 1071–1075.

Lerch R. (1990), Simulation of piezoelectric devices by two- and three-dimensional finite elements, IEEE transactions on Ultrasonics, Ferroelectric and Frequency Control, 37, 2, 233–247.

Martínez-Graullera O., Gomez-Ullate L., Romero D., Martín C.J., Godoy G. (2011), Design of Curvilinear Array Apertures for 3D Ultrasonic Imaging, [in:] Ultrasound Imaging, Ch. 2, Masayuki Tanabe [Ed.], INTECH, Rijeka, 17–36.

Medina J.E.S.M., Buiochi F., Adamowski J.C. (2006), Numerical modeling of a circular piezoelectric ultrasonic transducer radiating in water, ABCM Symposium Series in Mechatronics, 2, 458–464.

Nakamura K. (2012), Ultrasonic Transducers. Materials and Design for Sensors, Actuators and Medical Applications, Woodhead Publishing Limited, 722 pages.

Noliac: Piezoceramics specifications. www.noliac.com.

Opieliński K.J., Gudra T., Pruchnicki P. (2010), A digitally controlled model of an active ultrasonic transducer matrix for projection imaging of biological media, Archives of Acoustics, 35, 1, 75–90.

Opieliński K.J., Gudra T., Pruchnicki P. (2010), Narrow beam ultrasonic transducer matrix model for projection imaging of biological media, Archives of Acoustics, 35, 1, 91–109.

Opielinski K.J. (2012), Ultrasonic Projection, [in:] Ultrasonic Waves, Ch. 1, A. Dos Santos Junior [Ed.], INTECH, Rijeka, 29–58.

Opieliński K.J., Celmer M., Pruchnicki P., Roguski W., Gudra T., Majewski J., Bulkowski M., Piotrowski T., Wiktorowicz A. (2014), The effect of crosstalk in a circular transducer array on ultrasound transmission tomography of breast, Proceedings of Meetings on Acoustics, 21, 167th Meeting of the Acoustical Society of America, Providence, Rhode Island, 075001, 6 pages.

Opieliński K.J., Pruchnicki P., Gudra T., Podgórski P., Kurcz J., Kraśnicki T., Sąsiadek M., Majewski J. (2015), Imaging results of multi-modal ultrasound computerized tomography system designed for breast diagnosis, Computerized Medical Imaging and Graphics, 46, 83–94.

Powell D.J., Wojcik G.L., Desilets C.S., Gururaja T.R., Guggenberger K., Sherrit S., Mukherjee B.K. (1997), Incremental “Model-Build-Test” validation exercise for a 1-D biomedical ultrasonic imaging array, IEEE Ultrasonics Symposium, 2, 1669–1674.

Sherrit S., Mukherjee B.K. (2012), Characterization of Piezoelectric Materials for Transducers, [in:] Dielectric and Ferroelectric Reviews, Srowthi S.N., Bharadwaja and Robert A. Dorey[Eds.], Research Singpost, 175–244.

Song J., Xue Ch., He Ch., Zhang R., Mu L., Cui J., Miao J., Liu Y., Zhang W. (2015), Capacitive Micromachined Ultrasonic Transducers (CMUTs) for Underwater Imaging Applications, Sensors, 15, 23205–23217.

Viggen E.M. (2013), Acoustic multipole sources from the Boltzmann equation, 36th Scandinavian Symposium on Physical Acoustics, 5 pages.

Wildes D.G., Chiao R.Y., Daft C.M.W., Rigby K.W., Smith L.S., Thomenius K.E. (1997), Elevation performance of 1.25D and 1.5D transducer arrays, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 44, 1027–1037.

Wilm M., Armati R., Daniau W., Ballandras S. (2004), Cross-talk phenomena in a 1-3 connectivity piezoelectric composite, JASA, 116, 5, 2948–2955.

Wong S.H., Kupnik M., Watkins R.D., Butts-Pauly K., Khuri-Yakub B.T. (2010), Capacitive Micromachined Ultrasonic Transducers for Therapeutic Ultrasound Applications, IEEE Transactions on Biomedical Engineering, 57, 1, 114–123.

Wójcik J. (1998), Conservation of energy and absorption in acoustic fields for linear and nonlinear propagation, Journal of Acoustical Society of America, 104, 5, 2654–2663.

Zhou S., Wojcik G.L., Hossack J.A. (2003), An Approach for Reducing Adjacent Element Crosstalk in Ultrasound Arrays, IEEE Transactions on Ultrasonics,

Ferroelectrics, and Frequency Control, 50, 12, 1752–1761.

DOI: 10.1515/aoa-2016-0058

Copyright © Polish Academy of Sciences & Institute of Fundamental Technological Research (IPPT PAN)