Abstract
The present work details a novel approach to increase the transmitting sensitivity of piezoelectric micromachined ultrasonic transducer arrays and performing the direct modulation of digital information on the same device. The direct modulation system can reach 3× higher signal-to-noise ratio level and 3× higher communication range (from 6.2 cm boosted to 18.6 cm) when compared to more traditional continuous wave drive at the same energy consumption levels. When compared for the same transmission performance, the direct modulation consumes 80% less energy compared to the continues wave. The increased performance is achieved with a switching circuit that allows to generate a short high-AC voltage on the ultrasonic array, by using an LC tank and a bipolar junction transistor, starting with a low-DC voltage, making it CMOS-compatible. Since the modulation signal can directly be formed by the transmitted bits (on/off keying encoding) this also serve as the modulation for the data itself, hence direct modulation. The working principle of the circuit is described, optimization is performed relative to several circuital parameters and a high-performance experimental application is demonstrated.
Highlights
Ultrasonic transducers are devices that are able to generate ultrasonic waves and propagate them in either air or water-like media
The generation of the ultrasonic waves is due to the displacement of a membrane that consists of a piezoelectric layer, sandwiched between two electrodes, and a structural layer, all suspended on top of a cavity trenched on the handling wafer Figure 1b
The higher the voltage, the higher the membrane displacement, and the output pressure generated by the pMUT
Summary
Ultrasonic transducers are devices that are able to generate ultrasonic waves and propagate them in either air or water-like media (water, de-ionized water, silicone oil, castor oil, tissue phantom or human tissue). The higher the voltage, the higher the membrane displacement, and the output pressure generated by the pMUT These devices can be used for a wide variety of applications, such as fingerprint sensors [5,6,7], range finders [8,9,10], power transfer [11,12,13], medical imaging [14,15,16,17,18], and more recently, for intra-body and underwater communication [19,20,21,22]. In order to extend the range of transmission and minimize the power consumption, there is the need for more sensitive elements This translates into higher output pressure given a fixed input voltage (transmitter sensitivity) and higher received voltage given a fixed input pressure (receiver sensitivity). The most commonly used technique to increase the sensitivity is to combine single pMUTs into arrays and to make the latter work as a single radiating element [23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
