• 전자공학회논문지 IE
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• v.48 no.2
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• pp.40-46
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• 2011

In this study, PZT-5A green sheet were prepared by using tape casting technique, and the piezoelectric properties of PZT-5A by variation of sintering temperature was investigated. After, design and piezoelectric properties of 2-2 piezocomposite ultrasonic transducers by menas of the FEA. The acoustic impedance and piezoelectric charge constant of the 2-2 type piezocomposite transducer decreased proportionally due to the density decrease caused by the PZT volume fraction decrease. The piezocomposite acoustic impedance were 7~3 MRayl between 0.6 and 0.2 allowing it to be used for a ultrasonic transducer. The resonance characteristics and the electro-mechanical coupling factor were the best when the volume fraction PZT was 0.6. The PZT volume fraction shows the fixed value, 0.6~0.65, approximately within the range between 0.2 and 0.6 while it is increased to decreased over the range. The result of the experiment above confirmed that the 2-2 piezoelectric composites could be used as the ultrasonic transducers.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.3
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• pp.196-213
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• 2001

A split beam ultrasonic transducer operating at a frequency of 70 kHz to use in the fish sizing echo sounder was developed and the acoustic radiation characteristics were experimentally analyzed. The amplitude shading method utilizing the properties of the Chebyshev polynomials was used to obtain side lobe levels below -20 dB and to optimize the relationship between main beam width and side lobe level of the transducer, and the amplitude shading coefficient to each of the elements was achieved by changing the amplitude contribution of elements with 4 weighting transformers embodied in the planar array transducer assembly. The planar array split beam transducer assembly was composed of 36 piezoelectric ceramics (NEPEC N-21, Tokin) of rod type of 10 mm in diameter and 18.7 mm in length of 70 kHz arranged in the rectangular configuration, and the 4 electrical inputs were supplied to the beamformer. A series of impedance measurements were conducted to check the uniformity of the individual quadrants, and also in the configurations of reception and transmission, resonant frequency, and the transmitting and receiving characteristics were measured in the water tank and analyzed, respectively. The results obtained are summarized as follows : 1. Average resonant and antiresonant frequencies of electrical impedance for four quadrants of the split beam transducer in water were 69.8 kHz and 83.0 kHz, respectively. Average electrical impedance for each individual transducer quadrant was 49.2$\Omega$ at resonant frequency and 704.7$\Omega$ at antiresonant frequency. 2. The resonance peak in the transmitting voltage response (TVR) for four quadrants of the split beam transducer was observed all at 70.0 kHz and the value of TVR was all about 165.5 dB re 1 $\mu$Pa/V at 1 m at 70.0 kHz with bandwidth of 10.0 kHz between -3 dB down points. The resonance peak in the receiving sensitivity (SRT) for four combined quadrants (quad LU+LL, quad RU+RL, quad LU+RU, quad LL+RL) of the split beam transducer was observed all at 75.0 kHz and the value of SRT was all about -177.7 dB re 1 V/$\mu$Pa at 75.0 kHz with bandwidth of 10.0 kHz between -3 dB down points. The sum beam transmitting voltage response and receiving senstivity was 175.0 dB re 1$\mu$Pa/V at 1 m at 75.0 kHz with bandwidth of 10.0 kHz, respectively. 3. The sum beam of split beam transducer was approximately circular with a half beam angle of $9.0^\circ$ at -3 dB points all in both axis of the horizontal plane and the vertical plane. The first measured side lobe levels for the sum beam of split beam transducer were -19.7 dB at $22^\circ$ and -19.4 dB at $-26^\circ$ in the horizontal plane, respectively and -20.1 dB at $22^\circ$ and -22.0 dB at $-26^\circ$ in the vertical plane, respectively. 4. The developed split beam transducer was tested to estimate the angular position of the target in the beam through split beam phase measurements, and the beam pattern loss for target strength corrections was measured and analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1645-1652
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• 2013

In this paper, a new piezoelectric transducer for high performance ultrasonic flaw detector used in non-destructive test (NDT) is implemented. Here, the goals for some major characteristics such as piezoelectric strain constant and electro-mechanical coupling factor are fixed in advanced. Then, the parameters obtained by finite element analysis (FEA) are exploited to design and implement the piezoelectric transducer. As a result of experiments using manufactured samples, it is proved that the new PZT ceramics satisfy the goals very well. It has much improved impedance characteristic at the resonant frequency and generation of ultrasonic signals. In addition, ultrasonic flaw detector with the new transducer provides increased flaw detecting gain than the conventional one. Thus, it is considered that the new flaw detector contributes significantly to improve reliability of the NDT.

• The Journal of the Acoustical Society of Korea
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• v.19 no.7
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• pp.3-6
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• 2000

Because the generally reported radiation impedance has been calculated for vibrating surface with infinite baffle, the results have difficulties to apply for design of the real transducers with finite baffle. In this paper, with assuming a vibrating surface as a set of small point sources, a new calculation method for the vibrating surface with finite baffle is suggested by considering the effect of finite baffle on the source strength of each point source. As an example, the variation of self-radiation impedance for rectangular vibrating surface is calculated according to the size of baffle. The results show that the suggested method is useful.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1259-1263
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• 2004

In this paper, the optimum design of ultrasonic dry cleaning head was investigated. The transducer instead of mechanical dynamic structure was used to generate ultrasonic wave and the horn-shape amplifier was utilized to solve the energy decaying problem of ultrasonic wave with propagating it through the media. The analyses of ultrasonic wave and a fluid for the selected structure of a cleaning head were carried out using SYSNOISE and ANSYS simulators, respectively. Based on simulator results, the distance between a horn and the substrate of 4 mm and the horn diameter of 10 mm were determined to maximize the energy of ultrasonic waves. The cooling structure was also considered to reduce the heat from the transducer and the horn. The equivalent circuit for the fabricated horn was deduced from HP4194A impedance/gain/phase analyzer and the frequency of an ultrasonic wave of 20.25 kHz was confirmed using the parameters of the equivalent circuit.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.278-286
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• 2022

In this study, a 33-mode Free-Flooded Ring (FFR) transducer was designed to apply piezoelectric single crystal PIN-PMN-PT, which has high piezoelectric constants and electromechanical coupling coefficient. To ensure low-frequency high transmitting sensitivity characteristics with a small size of FFR transducer, the commercial FFR transducer based on piezoelectric ceramics was compared. To develop the FFR transducer with broadband characteristics, a piezoelectric segmented ring structure inserted with inactive elements was applied. The oil-filled structure was applied to minimize the change of acoustic characteristics of the ring transducer. It was verified that the transmitting voltage response, underwater impedance, and beam pattern matched the finite element numerical simulation results well through an acoustic test. The difference in the transmitting voltage response between the measured and the simulated results is about 1.3 dB in cavity mode and about 0.3 dB in radial mode. The fabricated FFR transducer had a higher transmitting voltage response compared to the commercial transducer, but the diameter was reduced by about 17 %. From this study, it was confirmed that the feasibility of a single crystal-applied FFR transducer with compact size and high-power characteristics. The effectiveness of the performance prediction by simulation was also confirmed.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1199-1201
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• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT was preapred from the mixture of PZT and PVA powders by BURPS(BURnout plastic Sphere) technique. The acoustic properties with various plastic sphere wt.% were studied. The acoustic impedance of porous PZT was smaller than that of single phase PZT ceramics. And the pulse-reponse of porous PZT maded transducer was significantly advanced to that of solid PZT maded transducer.

• Journal of the Korean Ceramic Society
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• v.27 no.1
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• pp.74-78
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• 1990

In this study, to develope the ultrasonic transducer element, the extrusion method which is the processing technique of the piezoelectric composite materials is introduced, the connectivity of the piezoelectric composite materials is the 1-3 type, and we study the properties of the materials. The electromechanical coupling factor(kt) of the materials is above 0.6, the resonance property(fr) is the thickness mode in the frequency range of 0.5 to 2 [MHz] and the acoustic impedance(Zac) is about 5 to 7 [Maryl]. From these results, it is known that the piezoelectric composite materials manufactured byt he extrusion method will be able to develope the ultrasonic transducer elements.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.717-722
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• 2013

In this study, we investigated the design of a wire wedge bonding ultrasonic tool horn using finite element method (FEM) simulations. The proposed method is based on an initial design estimate obtained by FEM analysis. An ultrasonic excitation causes various vibrations of a transducer horn and capillary. A simulated ultrasonic transducer horn and resonator are then built and characterized experimentally using a laser interferometer and electrical impedance analyzer. The vibration characteristics and resonance frequencies close to the exciting frequency are identified using ANSYS. FEM analysis is developed to predict the resonance frequency of the ultrasonic horn and use it in the optimal design of an ultrasonic horn mode shape.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.90-94
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• 2005

As the structure of the piezoelectric bimorph cantilever becomes increasingly more complicated, a more accurate and efficient analysis of piezoelectric media is needed. In this paper, the piezoelectric transducer is analyzed by using the three-dimensional finite element method. The validity of the three-dimensional finite element routine is confirmed by comparing the experimental result. The resonance characteristics, such as resonance frequency and anti-resonance frequency, of the piezoelectric cantilever are calculated by the experimentally verified three dimensional finite element method. Subsequently, the characteristics, such as mechanical displacement and impedance, are calculated at the resonance frequency. Besides, to design the piezoelectric bimorph cantilever shape that maximizes displacement at the tip, the ES (Evolution Strategy) algorithm is applied. Finally, optimal design for the fan of the piezoelectric cantilever is fulfilled to obtain maximum displacement at the tip. From these results, the application potentiality of the piezoelectric bimorph cantilever fan is identified.