source: © 2018 IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Ultrasound detection is commonly performed by piezoelectric transducers that are optimized for a specific application. Since the piezoelectric technology is not configurable, transducers designed for one application may not be compatible with other applications. In addition, some designs of ultrasound transducers may be difficult to implement owing to production constraints. In this paper, we propose a simple, low-cost method to reconfigure the geometry of ultrasound transducers. The technique is based on using apertures in thin sheets of acoustic blockers. We experimentally demonstrate this method for an ultrasound transducer with a central frequency of 1 MHz and show that it can emulate detectors of various sizes. An added advantage of this technique is its capability to achieve semi-isotropic detection sensitivity due to diffraction when the aperture size is comparable to the acoustic wavelength even when the angular sensitivity of the transducer is inherently limited.[Read More…]
Fig. 1 (a) Side view illustration of the detection scheme used in this paper. An ultrasound blocking mask with an aperture is placed in front of a large-area ultrasound receiver, resulting in an emulated detector whose detection characteristics depend on the aperture geometry. (b) Illustration of the experimental setup in which the emulated detector was used to characterize the 2-D diffraction map from an ultrasound transmitter. (c) Illustration of the setup used for characterizing the angular sensitivity of the emulated detector. (b) and (c) Transmitter was scanned in the xy plane while keeping the same z value for the transmitter, the receiver, and the aperture mask centers.
