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对所研制的硅微压电超声换能器(PMUT)的振动特性进行了研究分析。对硅微压电超声换能的振动膜薄板的厚度相对于薄板的尺度(边长)而言较薄的情况,理论分析与实验结果均表明残余应力对换能器的谐振频率影响较大:不考虑残余应力的理论分析得出的换能器谐振频率与器件的实验测量的结果相差较大,而考虑残余应力的分析给出的谐振频率结果与实验结果是符合的。本文还对所制作的硅微压电超声换能器的谐振频率及导纳进行测量,并给出其等效电路参数。其中振动膜边长为1mm的换能器的谐振频率为71.25 kHz。最后对其进行了简单接收发射实验,测得谐振频率处的接收灵敏度为-201.6 dB(ref 1 V/μPa),发射电压响应约为137 dB(ref 1μPa·m/V)。
The vibration characteristics of the developed silicon micro-piezoelectric ultrasonic transducer (PMUT) were studied and analyzed. The theoretical analysis and experimental results show that the residual stress affects the resonant frequency of the transducers to a great extent when the thickness of the vibrating thin film transduced by silicon micro-piezoelectric ultrasonic transducers is thin with respect to the dimension of the thin plate. The theoretical analysis of the residual stress does not take into account the resonance frequency of the transducer and the experimental results of the device are quite different, but considering the analysis of the residual stress gives the resonant frequency and the experimental results are in line with. The resonant frequency and admittance of the produced silicon micro-piezoelectric ultrasonic transducer are also measured and the equivalent circuit parameters are given. The vibration frequency of the transducer with 1mm side diaphragm is 71.25 kHz. Finally, a simple receiving and transmitting experiment was carried out. The receiving sensitivity at the resonant frequency was -201.6 dB (ref 1 V / μPa) and the emission voltage response was about 137 dB (ref 1μPa · m / V).