Journal ID : TRKU-21-09-2020-11130
[This article belongs to Volume - 62, Issue - 09]
Total View : 402

Title : Flexible based Piezoelectric Ultrasonic Transducer with Air Backing for Wideband High-Frequency Underwater Ultrasonic Applications

Abstract :

High-frequency ultrasonic transducer has been used in an underwater non-destructive application, underwater acoustic imaging, and high-frequency sonar. Normally, all these applications need a high-resolution transducer. For this reason, the transducer must be a high-resolution transducer subsequently, the transducer must be a good receiving sensitivity and wide bandwidth. In this paper, a flexible piezoelectric ultrasonic transducer (FPUT) was designed and characterized in an open-circuit receiving response for underwater application. The target operating frequency is a high-frequency ultrasonic range between 25 kHz to 1.5 MHz for an acoustic transducer. Polyimide is used as a flexible substrate for the cover layer and the flexible circuit. The electrodes for positive potential and ground were designed in a lateral structure whereby this design can improve the receiving sensitivity. A Polyvinylidene fluoride (PVDF) film was functioning as a sensing element and placed on the top of an electrode. A polyimide layer is used as it is a semipermeable membrane manufactured principally for use in water purification or water desalination systems. A 3M tape was used as a matching layer interface between water and PVDF. The air backing was used as a signal absorber to expand the frequency bandwidth. The pulse-echo method is used to characterize the sensitivity of ultrasonic transducer in underwater. The receiving sensitivity and frequency bandwidth are two important parameters to describe the electro-acoustic energy conversion efficiency of an ultrasonic transducer. An FPUT has a receiving sensitivity of -25.1827 dB rel 1 V/┬ÁPa dB with a resonance frequency of 425 kHz. The frequency bandwidth of this FPUT is 61.2%. This can conclude that a FPUT with air backing is capable to be a high receiving sensitivity ultrasonic transducer and wide frequency bandwidth for high-frequency ultrasonic applications

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