K. H. (Koko) LAM Research group

K. H. (Koko) Lam - The Hong Kong Polytechnic University © All rights reserved.

Ultrasonic Transducer Technology

Ultrasonic transducers have been widely employed in many different areas including biomedical imaging and NDE applications. The transducers developed previously were mainly used for biomedical imaging applications, microfluidic applications and microbeam applications.

One of the main contributions is to develop ultrahigh frequency transducers for resolution enhancement. With using a lead–free KNN/BNT thick film, I developed a ceramic ultrasonic transducer with the highest center frequency (>300 MHz) ever reported. It was found that the experimental data was in good agreement with the modeling results.​

Selected Publications:

Lam, K.H.*, et al. Ultrasonics, Vol.53, pp.1033-1038 (2013).

Besides the single–element transducers, array transducers were also studied including linear array, phased array and annular array for specific applications. ​

Selected Publications:

Chen, R.M., Wu, J.C., Lam, K.H., et al. The IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol.59(12), pp.2777–2784 (2012)
​Cheung, K.F., Zhou, D., Lam, K.H., et al. Sensors and Actuators: A, Vol.172(2), pp.511-515 (2011) 

Dai, J.Y., Cheung, K.F., Zhou, D., Chiu, Y.C, Lam, K.H., et al. Chinese Patent Appl. No. 201110132195.1 (25/05/2011).

Research effort on ultrasonic transducers also involves the development of a mechanical dimpling technique that is used to fabricate focused transducer elements. Compared to the conventional press–focused technique, the mechanical dimpling technique would not damage the transducer element during the shaping process. This technique can be used for all kinds of materials including fragile single crystals. 

Selected Publications:

Lam, K.H., et al. Chinese Patent No. ZL201010542689.2, Sep. 2013

Lam, K.H., et al. U.S. Patent No. US20120123272, May 2012

Lam, K.H.*, et al. Ultrasonics, Vol.52(1), pp.20–24 (2012) 

In the study of ultrasonic transducers, biomedical imaging is one of main research applications. Fluid analysis is also the other application of ultrasonic transducer. By measuring the velocity of sound in the solution, the potassium chloride content can be determined. 

Selected Publications:

Yan, X., Lam, K.H., et al. The IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol.60(7), 1537 (2013)

Lee, S.T.F., Lam, K.H., et al. Review of Scientific Instruments, Vol.82, 024903(2011)