Page 176 - 《应用声学》2022年第1期

172 2022 年 1 月

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10ὃ 50ὃ
20 20ὃ 60ὃ -50
30ὃ 70ὃ
40ὃ 80ὃ -60
10 90ὃ -70
ࣨϙ/mV 0 Ҫဋ៨/dB -80 10ὃ

30ὃ
-90 20ὃ
40ὃ
-10 50ὃ
-100 60ὃ
70ὃ
-110 80ὃ
-20 90ὃ
-120
5 6 7 8 9 10 0 1 2 3 4 5 6 7 8
௑ᫎ/ms ᮠဋ/MHz
(a) ௑۫ڏ (b) ࠫ஝Ҫဋ៨ڏ
图 8 不同脉冲占空比时的时域与频域图
Fig. 8 Time domain and frequency domain diagrams with different pulse duty cycle

5 结论 [3] Park K K, Lee H, Kupnik M, et al. Fabrication of ca-
pacitive micromachined ultrasonic transducers via local
本文根据 CMUT 阵元的工作原理，设计了脉 oxidation and direct wafer bonding[J]. Journal of Micro-
冲驱动电路，编写控制程序通过 FPGA 控制方波脉 electromechanical Systems, 2011, 20(1): 95–103.
[4] Haller M I, Khuri-Yakub B T, Control F. A surface
冲的各项参数。采用串行匹配消除脉冲信号的过
micromachined electrostatic ultrasonic air transducer[J].
冲现象，避免因尖峰脉冲损坏 CMUT阵元。探究了 IEEE Transactions on Ultrasonics, Ferroelectrics, and Fre-
CMUT 的声发射特性与激励信号的脉冲个数及其 quency Control, 1996, 43(1): 1–6.
占空比的对应关系。随着激励信号脉冲个数增加， [5] Yaar A R, Yldz F, Eroul O J M T. Capacitive microma-
chined ultrasonic transducer: transmission performance
CMUT输出声信号的有效带宽逐渐变窄，二次谐波
evaluation under different driving parameters and mem-
逐渐明显；随着激励信号脉冲占空比增加，CMUT brane stress for underwater imaging applications[J]. Mi-
的输出声压先增大后减小，二次谐波先减小后增大。 crosystem Technologies, 2020, 26: 3601–3611.
在占空比为50%时输出声压最大，且二次谐波最小。 [6] Chen K, Lee H S, Chandrakasan A P, et al. Ultrasonic
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上述研究结果为后续 CMUT 的应用与测试提供了 pulse-shaping pulser with improved efficiency and a noise-
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