한수지 50(5), 605-615, 2017 Original Article Korean J Fish Aquat Sci 50(5),605-615,2017 다중공진광대역음향변환기의대역폭개선 이대재 * 부경대학교해양생산시스템관리학부 Bandwidth Improvement of a Multi-resonant Broadband Acoustic Transducer Dae-Jae Lee* Division of Marine Production System Management, Pukyong National University, Busan 48513, Korea A multi-resonant broadband acoustic transducer with six Tonpilz elements operating at different resonant frequencies in a transducer assembly was fabricated, tested, and analyzed. A compensated transducer, modified by adding series inductance to the developed multi-resonant broadband transducer, was shown to provide improved bandwidth performance with a relatively more uniform frequency response compared with the uncompensated transducer. By controlling the series inductance, flat frequency response characteristics at two frequency bands were obtained over the range 38-52 khz with 1.1 mh inductance and 50-60 khz with 0.4 mh inductance. These results suggest that the operating frequency of the developed multi-resonant broadband transducer in a chirp echo sounder can be shifted to a different frequency band that is optimized according to the environment for more effective echo surveys of fishing grounds. Key words: Multiple resonance, Broadband acoustic transducer, Matching inductance, Bandwidth improvement 서론 (sonar) (narrowband acoustic transducer) (Stansfield, 1991)., (broadband acoustic transducer) (Coates and Maquire, 1989; Ramesh and Ebenezer, 2008; Huang and Paramo, 2011; Airmar, 2013). head mass (Inoue et al., 1989), Tonpilz (Hawkins and Gough, 1996; Yao and Bjorno, 1997; Rajapan, 2002; Kim et al., 2013), (Kachanov and Sokolov, 2007; Lee, 2014; Lee et al., 2014), (Coates and Mathams, 1988; Coates, 1991; Stansfield, 1991; Radmanovic and Mancic, 2004). (Lee et al., 2014),, (transmitting voltage response, TVR) (ripple).,.,,. https://doi.org/10.5657/kfas.2017.0605 Korean J Fish Aquat Sci 50(5) 605-615, October 2017 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 27 September 2017; Revised 7 October 2017; Accepted 12 October 2017 *Corresponding author: Tel: +82. 51. 629. 5889 Fax: +82. 51. 629. 5885 E-mail address: daejael@pknu.ac.kr Copyright 2017 The Korean Society of Fisheries and Aquatic Science 605 pissn:0374-8111, eissn:2287-8815
606 이대재 재료 및 방법 초음파 진동소자의 제작과 배열 본 연구에서는 공진주파수가 서로 다른 6개 주파수의 tonpilz 형 진동체를 설계, 제작한 후, Fig. 1a에서와 같이 2 3 패턴 으로 배열하여 Fig. 1b의 다중공진 음향변환기를 개발하였다. Fig. 1a의 tonpilz형 진동체는 외경, 내경 및 두께가 각각 25 mm, 8 mm, 5 mm인 2개의 PZT 세라믹 링(PZ26, Ferroperm Piezoceramics, Denmark)을 서로 전극면이 반대가 되도록 적 층한 후, 전면과 후면에 각각 알류미늄 재질의 head mass와 tail mass를 고강력 stud bolt로서 체결한 형태이다. 이들 진동체 의 head mass는 가로와 세로가 각각 30 mm, 높이는 주파수에 따라 12-40 mm 범위였다. tail mass는 외경과 내경이 각각 28 mm, 8 mm이었고, 높이는 주파수에 따라 13-20 mm 범위였다. 또한, 체결 stud bolt의 직경 및 길이는 각각 8 mm, 32 mm이었 다. 전기펄스신호를 공급하기 위한 전극판의 재질은 인청동으 로서, 그 외경, 내경 및 두께는 각각 30 mm, 8 mm, 0.2 mm이 었다. 본 연구에서는 Fig. 1a에 나타낸 6개 주파수의 tonpilz형 진동체를 우레탄 고무(scotchcast 2130, 3M, USA) 윈도(window)에 장착한 후, 폴리우레탄으로 수밀, 몰딩 처리하여 다중 공진 광대역 음향변환기를 완성하였다. 다중 공진 음향변환기의 전기적인 등가회로 본 연구에서 설계, 제작한 다중 공진 광대역 음향변환기의 전 기적인 등가회로는 Fig. 2와 같다(Coates and Maguire, 1989; Ramesh and Ebenezer, 2008; Huang and Paramo, 2011). Fig. 2a의 등가회로에는 Fig. 1에 나타낸 6개의 각 tonpilz 진동소 자에 대한 직렬공진 등가회로가 병렬로 접속되어 있는데, 이들 모든 진동소자에 대한 제동용량(clamped capacitance)은 합성 정전용량 Co로서 나타내었다. 이들 각 등가회로 branch에서 전기소자 R, C, L은 각각 저항, 인덕턴스(inductance), 커패시 턴스(capacitance)이다. Fig. 2a에는 음원(전력 증폭기)의 출력 임피던스 Rs와 음향변환기로부터 방사되는 음향출력의 불규칙 Fig. 1. Photographs of the 6 tonpilz transducer elements operating at different resonance frequencies and the multi-resonant broadband acoustic transducer developed in this study. The transducer elements were arranged in a 2 3 array configuration on the acoustic window of polyurethane. Rs Vi Ls C0 Rs Ls C1 C3 C6 L1 L3 L6 R1 R3 R6 C1 C3 C6 array transducer Vi C0 L1 L3 L6 Rs jxl -jxc Vi Rs jxl matching network RL array -jx transducer C Vi Fig. 2. Electrical equivalent model for a 2 3 array RLresistance and R1 transducer R3to account for R6 multiple resonant frequencies with a source a series matching inductor. Series representation of input electrical impedance for a 2 3 array transducer with an inductive reactance for eliminating or minimizing the capacitive reactance in the frequency band of interest. array transducer matching network array transducer
다중공진광대역음향변환기의대역폭개선 607 ripple ( ) (tuning inductance) L s., Fig. 2b Fig. 2a (conjugate input electrical impedance) Z( ) resistance R L ( ) reactance X c ( )., Z( ) Z( ) = R L ( ) + jx C ( ) (1), (f) X L ( ) = X C ( ) (2) L s ( ) = X C (ω) (3)., = 2 f. (3) ripple L s. 1, (f s )., reactance X C ( ) (matching inductor)., Fig. 2a 6 (i = 1-6) (admittance) Y( ), (conductance) G pi ( ), (susceptance) B pi ( ), tonpilz R i, L i, C i C o (Coates and Maguire, 1989; Ramesh and Ebenezer, 2008; Huang and Paramo, 2011). Y( ) = N Y i ( ) = N {G pi ( ) + jb pi ( )} (4) i = 1 i = 1 G pi ( ) = 2 C i 2 R i (5) 2 C i 2 R i 2 +(1-2 L i C i ) C B pi ( ) = C o + i (1-2 L i C i ) 2 C 2 i R 2 i + (1-2 L i C i ) R i = 1 G pi (ω si ) (6) (7) S 2 C o = 1 - N + N 2 pi 2 i = 1 si (8) C i = C o { 2 pi -1} (9) 2 si L i = 1 si 2 C i (10), f si i tonpilz ( si = 2 f si ), f pi i tonpilz ( pi = 2 f pi )., S ( Y( ) ) zero, S = d Y(ω) d, 30 khz d Y( ) (Coates and Maguire, 1989). 음향변환기의주파수응답특성측정, LCR meter (7600, QuadTech, USA)., (receiving sensitivity, SRT) (L B D, 5 6 5 m)., Fig. 3 chirp (33120A, HP, USA), (Dong and Cui, 2012; Lee et al., 2016). Fig. 3 400 mv, 1-70 khz chirp (2713, B&K, Denmark),. (model 8100, B&K, Denmark), (model 2610, B&K, Denmark), (DS1530, EZ, Korea) FFT (3525, AND, Japan).. 결과및고찰 다중공진음향변환기의어드미턴스특성및정합인덕턴스의추정 측정및계산어드미턴스의비교 6 tonpilz.,
608 이대재 Fig. 3. Time-frequency response characteristic of chirp pulse signal at the electrical terminal of multi-resonant broadband transducer. (coupling)., Fig. 4. Fig. 4 Y( ), G p ( ) B p ( ),, (ms), (khz)., Fig. 4 (f si ) (f pi ) Table 1. Table 1 tonpilz (f si ) (f pi ), G pi ( si ) (7)-(10) C o R i, L i, C i, (4) Fig. 5. Fig. 5, (ms), (khz). Fig. 4 Fig. 5, tonpilz., Fig. 4 60.3, 65.1 68.5 khz Fig. Fig. 4. Measured admittance patterns of the multi-resonant broadband transducer with no tuning. The magnitude of admittance ( Y ) is in red and the conductance and susceptance is in black and purple, respectively. Table 1. Resonance (f s ) and anti-resonance frequencies (f p ) obtained from the measured admittance curve (Fig. 4) as a function of length (L) for 6 tonpilz elements of multi-resonant broadband acoustic transducer Element No. f s (khz) f p (khz) L(mm) 1 31.84 32.95 70 2 35.57 36.96 60 3 39.40 40.24 54 4 43.08 44.39 48 5 49.79 51.30 44 6 57.06 57.80 35
다중공진광대역음향변환기의대역폭개선 609 Fig. 5. Calculated admittance patterns of the multi-resonant broadband transducer with no tuning. The magnitude of admittance ( Y ) is in red and the conductance and susceptance is in black and purple, respectively. Fig. 7. Change of series inductance values as a function of frequency calculated from an inductive reactance for eliminating the capacitive reactance in Fig. 2. Fig. 6. Measured Impedance patterns of the multi-resonant broadband transducer with no tuning. The resistance is in red and the reactance is in black. 5., stress bolt,, head mass flapping,. Fig. 4 Fig. 5. 정합인덕턴스의추정, Fig. 4 (ripple).,,, 38-50 khz 50-60 khz Fig. 8. Measured conductance and susceptance patterns of the multi-resonant broadband transducer with no-tuning (purple), series tuning inductors of 0.4 mh (black) and 1.1 mh (red). resistance R L ( ) reactance X C ( ) Fig. 6., Fig. 6 reactance (3) Fig. 7. Fig. 6 Fig. 2b
610 이대재 Fig. 9. Transmitting time-frequency response and relative TVR spectrum of the multi-resonant broadband transducer with no tuning. resistance reactance., Fig. 7 Fig. 2b reactance X C ( ) L s ( ), Fig. 6 Fig. 7 (khz). Fig. 2b X L ( ) = X C ( ) R s = R L., Fig. 2a L s Fig. 4 Fig. 7 30-40 khz 50-60 khz, 0.9-1.7 mh 0.35-0.74 mh.,, 38-50 khz L s L s = 1.1 mh,, 50-60 khz L s L s = 0.4 mh,., Fig. 2a, Fig. 8. Fig. 8 a b. Fig. 2a L s = 0.4 mh, 30 khz 54-59 khz
다중공진광대역음향변환기의대역폭개선 611 Fig. 10. Transmitting time-frequency response and relative TVR spectrum of the multi-resonant broadband transducer with a 0.4 mh series tuning inductor.., L s = 1.1 mh, 35-38 khz,., 0.4 mh 59kHz, 1.1 mh 35kHz. (ripple). 다중공진음향변환기의송파및수파감도특성 정합인덕턴스에의한송파감도의보정 Fig. 2a L s, Fig. 9. Fig. 9 a -, b Fig. 3 Fig. 9a. Fig. 9a,
612 이대재 Fig. 11. Transmitting time-frequency response and relative TVR spectrum of the multi-resonant broadband transducer with a 1.1 mh series tuning inductor.. 0 db 0-30 db. Fig. 9b L s L s = 0 mh, 50 khz 60 khz, 50-60 khz -11.32dB, -2.70~1.57 db., 50 khz., Fig. 9 40-50 khz -12.05dB, -3.86~2.17 db., 6. Fig. 2a L s Fig. 9, Fig. 10 Fig. 11., Fig. 10 Fig. 9 50 khz 60 khz., Fig. 7 Fig. 9 50 khz 60 khz
다중공진광대역음향변환기의대역폭개선 613 Fig. 12. Receiving time-frequency response and relative SRT spectrum of the multi-resonant broadband transducer. reactance X C ( ) L s (0.4 mh), Fig. 2a. Fig. 10 a -, b Fig. 3 Fig. 10a. Fig. 10a,. 0 db 0-30 db. Fig. 8a Fig. 2a L s = 0.4 mh, 54-59 khz Fig. 9 50 khz 60 khz., 50 khz 60 khz., Fig. 10 50-60 khz -7.48 db,, -1.38 0.93 db., L s = 0 mh 3.84 db, 46%., Fig. 11 Fig. 9 50 khz
614 이대재., Fig. 7 Fig. 9 50 khz reactance X C ( ) L s (1.1 mh), Fig. 2a. Fig. 11 a -, b Fig. 3 Fig. 11a. Fig. 11a,. 0 db 0-30 db. Fig. 8a Fig. 2a L s = 1.1 mh, 35-38 khz Fig. 11 35 khz 52 khz., 38 khz 52 khz., Fig. 11 40-50 khz -8.43 db,, -1.55 0.63 db., L s = 0 mh 3.62 db, 64%. 다중공진음향변환기의수파감도특성 = 0.4 mh L s = 1.1 mh FOM. Fig. 13 FOM (db), (khz). Fig. 13 L s = 0 mh 40-50 khz FOM -25.14dB, FOM -5.75 2.86 db., 50-60 khz FOM -22.53dB, FOM -3.1 1.77 db., Fig. 2a L s = 0.4 mh, 50-60 khz FOM -18.69dB, FOM -2.23 1.00 db., Fig. 2a L s = 1.1 mh, Fig. 12. Fig. 12 a -, b. Fig. 12a,., 0 db 0-30 db. Fig. 12 50-60 khz -11.21dB, -2.72~1.06 db., 40-50 khz -13.09dB, -3.66~2.26 db. 다중공진음향변환기의 FOM 특성 FOM Fig. 13. Fig. 13 FOM Fig. 9-Fig. 11 (TVR) Fig. 12 (SRT) (TVR+SRT). Fig. 13 a Fig. 2a L s FOM, (c) L s Fig. 13. Comparison of FOM performance characteristics for the multi-resonant broadband transducer without and with 0.4 mh and 1.1 mh (c) tuning inductors.
다중공진광대역음향변환기의대역폭개선 615 40-50 khz FOM -21.59dB, -3.48 1.98 db., Fig. 2a 0.4 mh 1.1 mh FOM 50-60 khz 3.84 db, 30-40 khz 3.55 db., 50-60 khz 34%, 30-40 khz 37%. 사사 (2017 ). References Airmar technology corporation. 2013. Technical data catalog, Milford, NH, U.S.A., 274-325. Coates R. 1991. The design of transducers and arrays for underwater data transmission. IEEE J Ocean Eng 16, 123-135. http://dx.doi.org/10.1109/48.64891. Coates R and Maguire PT. 1989. Multiple-mode acoustic transducer calculations. IEEE Trans Ultrason Ferroelect Freq Contr 36, 471-473. Coates R and Mathams RF. 1988. Design of matching networks for acoustic transducers. Ultrasonics 26, 59-64. Dong Y and Cui Y. 2012. Analysis of a new joint time-frequency distribution of suppressing cross-term. Res J Appl Sci Eng Technol 4, 1580-1584. Hawkins DW and Gough PT. 1996. Multiresonance design of a Tonpilz transducer using the finite element method. IEEE Trans Ultrason Ferroelect Freq Contr 40, 782-789. Huang H and Paramo D. 2011. Broadband electrical matching impedance for piezoelectric ultrasonic transducers. IEEE Trans. Ultrason. Ferroelectr Freq Control 58, 2699-2707. http://dx.doi.org/10.1109/tuffc.2011.2132. Inoue T, Nada T, Tsuchiya T, Nakanishi T, Miyama T, Takahashi S and Konno M. 1989. Tonpilz piezoelectric transducer with acoustic matching plates for underwater colour image transmission. Acoust Imaging 17, 597-607. Kachanov VK and Sokolov IV. 2007. Requirement for choosing the parameters of broadband transducers for testing objects with high damping of ultrasonic signals. Russian J Nondestr Test 43, 743-754. http://dx.doi.org/10.1134/ S1061830907110058. Kim JW, Kim HY and Roh YG. 2013. Design and fabrication of multi-mode wideband Tonpilz transducers. J Acoust Soc Kor 32, 191-198. http://dx.doi.org/10.7776/ask.2013.32.3.191. Lee DJ. 2014. Bandwidth enhancement of a broadband ultrasonic mosaic transducer using 48 tonpilz transducer elements with 12 resonance frequencies. Korean J Fish Aquat Sci 47, 302-312. http://dx.doi.org/10.5657/kfas. 2014.0302. Lee DJ, Kwak MS and Kang HY. 2014. Design and development of the broadband ultrasonic transducer operating over the frequency range of 40 khz to 75 khz. Korean J Fish Aquat Sci 47, 292-301. http://dx.doi.org/10.5657/kfas. 2014.0292. Lee DJ, Kang HY and Pak YY. 2016. Time-frequency feature extraction of broadband echo signals from individual live fish for species identification. Korean J Fish Aquat Sci 49, 214-223. http://dx.doi.org/10.5657/kfas.2016.0214. Radmanovic M and Mancic D. 2004. Design and modeling of the power ultrasonic transducers. MP Interconsulting, Le Locle, Switzerland, 15-135. Rajapan D. 2002. Performance of a low-frequency, multi-resonant broadband Tonpilz transducer. J Acoust Soc Am 111, 1692-1694. http://dx.doi.org/10.1121/1.1456927. Ramesh R and Ebenezer DD. 2008. Equivalent circuit for broadband underwater transducer. IEEE Trans Ultrason Ferroelect Freq Contr 55, 2079-2083. http://dx.doi.org/10.1109/ TUFFC.899. Stansfield D. 1991. Underwater electroacoustic transducers. Bath University Press, Bath, UK, 119-141. Yao Q and Bjorno L. 1997. Broadband Tonpilz underwater acoustic transducers based on multimode optimation. IEEE Trans Ultrason Ferroelect Freq Contr 44, 1060-1066.