MEMS ultrasonic transducers are potentially valuable in both medical and non-destructive testing applications. A prime advantage of these transducers is their wide bandwidth together with the potential for economical fabrication of detector arrays. In this paper, we discuss issues related to the coupling of these transducers to solid and liquid media. We will show that appropriate choice of the...

This chapter is dedicated to ultrasonic piezoelectric ceramic power transducers. These elements are now the most popular source of high power ultrasound and is used in many industrial applications. High power ultrasonic waves are generally used in such industrial processes as welding, acceleration of chemical reactions, scavenging in gas medium, echo sounding and underwater communication (sonar...

The amplitude of an ultrasonic signal generated by electromagnetic acoustic transducers (EMATs) is typically low when compared to those generated by contacting transducers, which restricts the application of EMATs in the fields of nondestructive testing and nondestructive evaluation. The transmission process of a surface wave EMAT is studied, based on a previously established 3-D model, with th...

Ultrasonic technology is in several ways ideally suited to cardiac research and to routine clinical examinations. It provides truly real time images and detailed information on moving anatomical structures and blood. The portable nature and relatively low cost of the equipment makes it well suited to use in hospitals. Ultrasonic technology for cardiology is still developing and in recent years ...

In the fields such as evacuation guidance and entertainment, it is important for each listener to provide different sound information by using some loudspeakers in a same room. However, listeners have difficulty obtaining target sound information because various sound signals are mixed by using a general loudspeaker which has a wide directivity. To solve this problem, a parametric loudspeaker w...

The reproducibility of ultrasonic measurements complicates the interpretation of measurement results. The signal from ultrasonic transducers varies for to several reasons, like manufacturing tolerances in a batch, cable length, amplifier properties etc. A known problem that is caused by this effect is the quantitative interpretation of C-scan images from laminates, particularly the porosity pre...

The problems of development of high-temperature ultrasonic transducers for modern science and technology applications are analysed. More than 10 piezoelectric materials suitable for operation at high temperatures are overviewed. It is shown that bismuth titanate based piezoelectric elements are most promisable. Bonding methods of piezoelectric elements to a protector and backing are discussed. ...