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Zhang K.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2015 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2015 | Year: 2015

There are many advantages of broadband transducers, such as reducing of signal distortion, widening the security about information transmission, reducing the ratio of false codes. The use of eight 33 mode single crystal pieces, a thin light beryllium alloy head mass and a thick heavy tungsten alloy tail mass can expand the bandwidth of the middle-frequency transducer. The one-fourth finite element model of transducer was set up with ANSYS software and the structure of the transducer was optimized. A final transducer was designed, fabricated and measured, and its longitudinal size is about 21mm. The bandwidth of the transducer is 17 kHz-120 kHz, in which the ripple of the transmitting voltage response does not exceed ±5dB. There are several conclusions from the research: the bandwidth of tonpilz transducers can be expanded by the use of single crystal pieces, beryllium alloy head mass and tungsten alloy tail mass; and it gives a method to achieve the broad-band projecting performance of middle-frequency transducers. © 2015 IEEE. Source


Bai L.-L.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

According to Berktay the far-field solution of parametric array, self-demodulatory sound pressure is proportional to squared of envelope function to the second derivative of the time. The excitation input signals of parametric array were designed and analyzed. A parameter array is measured under the different excitation signals. The results show that: (1) When the input signals is single-sideband amplitude modulatory signal the harmonic distortion of the sound field is relatively small compared to the double sideband amplitude modulated signal and the difference frequency wave acoustic source level is higher; (2) The difference frequency wave source level will increase rapidly with increase of input power of the parametric array. But too much power may cause the power amplifier to produce nonlinear, thus the harmonic amplitude increase and the conversion efficiency will be lower. © 2012 IEEE. Source


Zhang K.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

There many advantages of broadband transducers, such as reducing of signal distortion, widening the security about information transmission, reducing the ratio of false codes. The combine of piezoelectric pillars and dual matching layers can expand the bandwidth of the high-frequency transducer. The one-eighth finite element model of transducer was set up with ANSYS software and the structure of the transducer was optimized. A final transducer was designed, which used the first thickness mode, the second thickness mode and the third thickness mode. The bandwidth of the transducer is 47kHz-159kHz, in which the ripple of the transmitting voltage response does not exceed ±3dB. There are several conclusions from the research: the bandwidth of pillar transducers can be expanded by the first thickness mode, the second thickness mode and the third thickness mode, and it gives a method to achieve the broad-band projecting performance of high-frequency transducers. © 2012 IEEE. Source


Zheng Z.-Y.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

The equivalent circuit model of piezoelectric ceramic pillar transducer with matching layer material is proposed, and the applicability of this model in the U-shape transducer array is discussed. The vibration character and directivity pattern of the transducer are analyzed by the finite element method. The manufactured U-shape transducer array has verified feasibility of the piezoelectric ceramic pillar transducer with matching layer design. The broadband and high power density characters of such design are suitable for high frequency broadband acoustic emission with special directivity. © 2012 IEEE. Source


Xu X.-R.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

In this paper, a new structure with a perforated electrode design in free-flooded 33-mode ring transducer is proposed. The FEM is utilized to simulate the performance of the transducer, and several design parameters are optimized to achieve higher output power over a wider bandwidth. The tested performance of the manufactured transducers verify the validity of the design. The influence of different shape openings of transducer on its performance is also studied experimentally. © 2012 IEEE. Source

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