• Title/Summary/Keyword: acoustic transducer

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A Study on the Acoustic Properties of Acoustic Treansducer with PZT/Metal (PZT/Metal로 구성된 음향변환기의 음향특성에 관한 연구)

  • Kim, Jin-Soo;Kang, Dae-Ha;Kim, So-Jung;Kim, Ho-Gi;Lee, Deok-Chool
    • The Journal of the Acoustical Society of Korea
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    • v.11 no.2
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    • pp.28-37
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    • 1992
  • In the study, the Acoustic transducer of a thin circular disc-type with PZT/Metal was manufactured. The 'tape casting method' was introduced to prepare the thin disc-type of piezoelectric ceramics. The acoustic characteristics of PZT/Metal acoustic transducer for piezoelectric buzzer and piezoelectric speaker etc. have been studied and analyzed. As a result, the sound pressure level (dB), in the range from -6dB to -14dB, increased with increasing the piezoelectric coeffeicient ($d_{31}$) of ceramics. The optimal conditions of the sound pressure characteristics of acoustic transducer were that the radius ratio(${\eta}$) of ceramics and metal plate is 0.7-0.8 and the thickness ratio(${\beta}$) is 1.0, and the value were -15~-165dB.

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LSAW Velocity Measurement by Using a PVDF Line-Focus Ultrasonic Transducer (PVDF 직선집속 초음파 트랜스듀서에 의한 누설탄성표면파 속도 측정)

  • 윤혁준;하강열;김무준;윤종락
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.1
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    • pp.62-67
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    • 2001
  • Velocities of leaky surface acoustic waves (LSAW/sub s/) were measured by using a line-focus polyvinylidene fluoride (PVDF) transducer and compared with theoretically calculated ones. Isotropic materials of Cu, Al, fused quartz, and anisotropic one of Z-cut α-quartz crystal were used as specimens. The velocities were obtained by the separation time between wave components reflected directly from the surface of specimen and LSAW components according to the defocusing distance. The measured velocities well agree with the theoretical results within 1% error, and it was shown that the leaky pseudo-surface acoustic wave (LPSAW) as well as the LSAW propagates with the typical 6-fold anisotropy on the (0,0,1) surface of α-quartz.

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The Electro-Mechanical Signal Transformation of Piezo-Electric Transducer (압전식 탐촉자의 기계-전기 신호 변환)

  • Ahn, Tae-Won
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.2
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    • pp.110-115
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    • 2000
  • The electromechanical reciprocity identity is introduced to relate the voltage at the terminals of a transducer to the acoustic wavefields scattered from the specimen. The voltage at the terminals of the transducer is expressed as an integral equation in terms of the displacement and stress of the incident and scattered waves on the closed surface enclosing the scatterer. The equation is used to relate the voltage at the terminals of an acoustic microscope's transducer to the acoustic wavefields at the interface between the specimen and the coupling fluid. The voltage calculated using the integral equation is compared with the experimental result.

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A study for implementation of ultrasonic transducer in the prostate cancer hyperthermia (전립선암의 온열치료를 위한 초음파변환기 개발에 관한 연구)

  • Park, Mun-Kyu;Noh, Si-Cheol;Park, Jae-Hyun;Choi, Heung-Ho
    • Journal of Sensor Science and Technology
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    • v.18 no.5
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    • pp.377-384
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    • 2009
  • The ultrasonic hyperthermia for oncology has been developed and studied. The HIFU(high intensity focused ultrasound) is the most recent method to treat the tumor by using ultrasound. In this study, an insertion-type transducer for treating a prostate cancer, which can focus the ultrasonic beam mechanically and electrically, was designed and developed. The developed transducer was composed of three arrays, and each array has 32 elements. For the purpose of the mechanical focusing, both side arrays are slanted to the center array by $15^{\circ}$. With this structure, NFL(near field length) was set up as 30 mm. The PZT-4 and two matching layers were used, and the backing layer was excepted to prevent energy losses. The acoustic field analysis and the heating test were performed to evaluate the performance of developed transducer. The shape of an acoustic field, peak pressure, and acoustic pressure distribution were compared with numerical simulation. The NFL was 32 mm, the beam width was 5 mm, focal area was $40\;mm^2$, and peak pressure was 5.5 MPa. With heating by using developed transducer, the temperature increased up to $33^{\circ}C$ at focal zone. As a result of this study, the usefulness of suggested transducer for prostate cancer hyperthermia was confirmed by the acoustic field analysis and the heating test with TMM(tissue mimicking) phantom.

A Study of a Wideband Acoustic Transducer for Underwater Communication Using 1-3 Type Piezoelectric Transducer (1-3형 압전 복합체를 이용한 광대역 수중 통신용 음향 트랜스듀서에 관한 연구)

  • Lee, Kyung-Woo;So, Hyoung-Jong;Lim, Sil-Mook;Kim, Won-Ho;Cho, Wun-Hyun
    • Journal of Ocean Engineering and Technology
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    • v.22 no.2
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    • pp.65-71
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    • 2008
  • Recently, many researches in relation to data transmission with faster speed and greater volume, many researches have been carried out on sonar systems for underwater communication. According to these researches, an acoustic transducer for underwater communication requires wide bandwidth properties. In domestic researches for underwater communication sonar, an operating frequency in the range of $20{\sim}40\;kHz$ is used. In this paper, we propose anon-resonance type acoustic transducer for underwater communication. The TVR (transmitting voltage response) characteristics increased linearly as the frequency increased, and the RVS (receiving voltage sensitivity) characteristics were constant as the frequency increased. Traditional techniques for wide bandwidth transducershave a limit and a transmission loss difference at lower and higher frequency operating ranges. In this paper, the new transducer proposed decreased the transmission loss under some conditions. It was optimized with the FE analysis tool (ATILA) and evaluated using the TVR and the RVS characteristics in the range of $10{\sim}90\;kHz$. The value of TVR was 138 dB at 20 kHz and 148 dB at 40 kHz, and the differences was 12 dB. The value of RVS was $195{\pm}2\;dB$ and nearly constant. From theseresults, it is certain that the developed transducers can be used for an underwater communication network in the 1.3 km range with both a 20 kHz bandwidth and 30 kHz center frequency.

Estimation of Equivalent Circuit Parameters of Underwater Acoustic Piezoelectric Transducer for Matching Network Design of Sonar Transmitter (소나 송신기의 정합회로 설계를 위한 수중 음향 압전 트랜스듀서의 등가회로 파라미터 추정)

  • Lee, Jeong-Min;Lee, Byung-Hwa;Baek, Kwang-Ryul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.3
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    • pp.282-289
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    • 2009
  • This paper presents an estimation technique of the equivalent circuit parameters for an underwater acoustic piezoelectric transducer from the measured impedance. Estimated equivalent circuit can be used for the design of the impedance matching network of the sonar transmitter. A fitness function is proposed to minimize the error between the calculated impedance of the equivalent circuit and the measured impedance of the transducer. The equivalent circuit parameters are estimated by using the fitness function and the PSO(Particle Swarm Optimization) algorithm. The effectiveness of the proposed method is verified by the applications to a sandwich-type transducer and a dummy load. In addition, the impedance matching network is also designed by using the estimated equivalent circuit model.

Development of an Impedance Matching Layer in an Ultrasound Transducer with Gradient Properties

  • Jeong, Jihoon
    • Journal of Sensor Science and Technology
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    • v.27 no.6
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    • pp.374-379
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    • 2018
  • The piezocomposite transducer is widely used because it is highly efficient in transforming electric energy into mechanical energy, and its frequency range is broader than that of other types of ultrasound transducers. A general piezocomposite transducer is composed of an acoustic lens, impedance matching layers, piezoelectric materials, and backing layers. When an input voltage is applied to a piezoelectric material as an active material, it generates sound waves while vibrating. At that time, an impedance matching layer helps the sound waves to propagate forward while reducing the impedance mismatch that may occur at the interface between the active material and its front material. The impedance mismatch has a negative effect on the signal of an ultrasound transducer; thus, it is important to design a matching layer to overcome the issue. In this study, an optimized feature of a matching layer with gradient properties is studied. An objective function is defined to minimize both the average and the deviation of the reflection coefficients that are functions of the frequencies. As a result, an improvement in the signal characteristics with respect to the sensitivity and bandwidth is reported.

Power Supply of Ultrasonic Phased Array for Focus Control of Acoustic Pressure (음압 초점제어를 위한 초음파 위상배열의 전원 장치)

  • Jung, Hyung-Jon;Kim, Ui-Young;You, Bum-Jae;Choy, Ick
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.1
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    • pp.137-146
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    • 2019
  • The ultrasonic phased arrays are used for treating tumors in the human body by the focus control of the acoustic pressure at the desired position. The magnitude and phase of the surface acoustic pressure in each ultrasonic transducer is controlled by the magnitude and phase of the applied voltage to it. In this paper, the relationship between the applied voltage and the surface acoustic pressure of the ultrasound transducer is modelled, and the desired voltage is realized by PWM technique. The validity of the proposed method is verified by computer simulation of the focus control of a ultrasonic phased array composed of 61 ultrasonic transducers.

Design and output control technique of sonar transmitter considering impedance variation of underwater acoustic transducer (수중 음향 트랜스듀서의 임피던스 변화를 고려한 소나 송신기의 설계 및 출력 제어 기법)

  • Shin, Chang-Hyun;Lee, Yoon-Ho;Ahn, Byoung-Sun;Yoon, Hong-Woo;Kwon, Byung-Jin;Kim, Kyung-Seop;Lee, Jeong-Min
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.5
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    • pp.481-491
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    • 2022
  • The active sonar transmission system consists of a transmitter that outputs an electrical signal and an underwater acoustic transducer that converts the amplified electrical signal into an acoustic signal. In general, the transmitter output characteristics are dependent on load impedance, and an underwater acoustic transducer, which is a transmitter load, has a characteristic that the electrical impedance varies largely according to frequency when driven. In such a variable impedance condition, the output of the active sonar transmission system may become unstable. Hence, this paper proposes a design and control technique of a sonar transmitter for transmitting a stable transmission signal even under variable impedance conditions of an underwater acoustic transducer in an active sonar transmission system. The electrical impedance characteristics of the underwater acoustic transducer are experimentally analyzed, and the sonar transmitter is composed of a single-phase full-bridge inverter, an LC filter, and a matching circuit. In this paper, the design and output control method of the sonar transmitter is proposed to protect the transmitter and transducer. It can secure stable output voltage characteristics even if it transmits the Linear Frequency Modulation (LFM) signal. The validity is verified through the simulation and the experiment.

Numerical analysis of acoustic field inside sonar dome by using a beam tracing method and the theory of elastic wave propagation (빔 추적기법과 다층구조에서의 탄성파 전파이론을 적용한 소나돔 내부 음장 수치해석)

  • Han, Seung-Jin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.9 no.2 s.25
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    • pp.26-33
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    • 2006
  • A sonar dome is basically designed and installed to protect sonar array from shocks, sea wave slaps and floating matters. The acoustic wave passing through sonar dome, however, can be distorted in magnitude and phase. This paper presents a numerical method for predicting the steady-state sound pressure on the surface of transducer array in the sonar dome and typical results of sonar beam pattern affected by sonar dome. A beam tracing model with phase information and a multi-layered elastic boundary model are involved. A full three-dimensional sonar dome is modeled as a GRP acoustic window, a rubber coated steel baffle and a rubber coated steel hull. A transducer array is modeled as thick steel cylinder. There are some assumptions such as incidence of plane wave, specular reflection on boundary and directionality of transducer element.