本文選題：CMUT + 結(jié)構(gòu)設(shè)計　； 參考：《中北大學(xué)》2017年碩士論文

【摘要】：基于表面微加工工藝制作的電容式微機(jī)械超聲換能器具有結(jié)構(gòu)簡單、自身噪聲低、高機(jī)電耦合系數(shù)、高分辨率、高靈敏度、寬頻帶、與介質(zhì)阻抗匹配性好等優(yōu)勢,從被提出以后就得到廣大科研人員的關(guān)注,其在海底資源勘探、水下地形地貌探測以及醫(yī)療成像等領(lǐng)域有著廣泛的應(yīng)用前景,因此對CMUT展開理論分析和基礎(chǔ)應(yīng)用研究,有著極其重要的科研價值。主要研究內(nèi)容如下:(1)根據(jù)不同分析內(nèi)容,建立了3種CMUT模型。在振動模型中,計算圓形振動薄膜的振動位移方程;通過平行板電容模型研究了CMUT的塌陷電壓、機(jī)電耦合系數(shù)、接收靈敏度、發(fā)射聲壓等參數(shù);在等效電路模型中,詳細(xì)分析了有效電容、機(jī)械阻抗等參數(shù)。(2)應(yīng)用COMSOL Multiphysics建立了CMUT微元有限元模型。根據(jù)特征頻率分析,確定了CMUT微元薄膜半徑、薄膜厚度參數(shù);通過機(jī)電耦合分析研究電極厚度、電極半徑與塌陷電壓的關(guān)系,確定電極結(jié)構(gòu)參數(shù);在靜態(tài)分析中,研究薄膜在標(biāo)準(zhǔn)大氣壓下的位移和應(yīng)力變化情況,得出CMUT空腔高度。CMUT參數(shù)確定后,通過模態(tài)分析和諧響應(yīng)分析去驗(yàn)證所設(shè)計CMUT結(jié)構(gòu)參數(shù)的正確性,并根據(jù)瞬態(tài)分析研究CMUT在交直流信號激勵下的振動位移和速度。(3)指向性是CMUT在遠(yuǎn)場的重要特性之一,推導(dǎo)出CMUT微元、CMUT陣元和CMUT陣列指向性函數(shù),并詳細(xì)分析CMUT結(jié)構(gòu)參數(shù)對CMUT陣列指向性的影響,隨之確定CMUT陣元中的微元個數(shù)、CMUT陣元間距。根據(jù)聲場理論,推導(dǎo)CMUT微元、CMUT陣元和CMUT陣列的聲場聲壓分布公式。(4)在平行板電容模型,靜電力在CMUT的工作中發(fā)揮著不可替代的作用,由于靜電力具有非線性,使得CMUT在發(fā)射過程中存在非線性特性。為了消除、抑制CMUT的非線性,采用去除直流偏置電壓,以消除諧波分量;采用改變激勵信號類型,根據(jù)功率譜抑制效果,選用雙極性脈沖;依據(jù)倍角公式,采用線性和非線性補(bǔ)償方法,消除二次諧波分量。(5)根據(jù)實(shí)際應(yīng)用情況,本文研究CMUT芯片的封裝方法并設(shè)計封裝結(jié)構(gòu),并根據(jù)聲學(xué)理論,詳細(xì)分析CMUT外殼封裝的材料選擇、結(jié)構(gòu)參數(shù)、應(yīng)力大小、透聲系數(shù),最終實(shí)現(xiàn)CMUT的水密封裝。搭建CMUT實(shí)驗(yàn)系統(tǒng),對所設(shè)計的CMUT的發(fā)射性能、接收性能、指向性和帶寬性能進(jìn)行測試,測試結(jié)果表明,設(shè)計的CMUT陣列能夠滿足水下成像要求。
[Abstract]:The capacitive micro mechanical ultrasonic transducer based on the surface micromachining technology has the advantages of simple structure, low self noise, high electromechanical coupling coefficient, high resolution, high sensitivity, wide frequency band and medium impedance matching. There are extensive applications in the fields of detection and medical imaging, so the theoretical analysis and basic application of CMUT expansion are of great value. The main contents are as follows: (1) 3 kinds of CMUT models are established according to the content of different analysis. The board capacitance model has studied the CMUT collapse voltage, the electromechanical coupling coefficient, the receiving sensitivity, the acoustic pressure and so on. In the equivalent circuit model, the effective capacitance, mechanical impedance and other parameters are analyzed in detail. (2) the finite element model of CMUT microelement is established by using the COMSOL Multiphysics. According to the characteristic frequency analysis, the radius of the CMUT microelement film is determined. The thickness of the film, the relationship between the electrode thickness, the radius of the electrode and the collapse voltage are studied by mechanical and electrical coupling analysis, and the parameters of the electrode structure are determined. In the static analysis, the displacement and stress change of the thin film at the standard atmospheric pressure are studied, and the.CMUT parameters of the CMUT cavity height are determined and verified by the modal analysis and the analysis of the harmonic response. The correctness of CMUT structure parameters is designed, and the vibration displacement and velocity of CMUT under AC and DC signal excitation are studied by transient analysis. (3) directivity is one of the important characteristics of CMUT in far field, CMUT microelement, CMUT element and CMUT array directivity function are derived, and the influence of CMUT structure parameters on the directivity of CMUT array is analyzed in detail. According to sound field theory, the sound pressure distribution formula of CMUT microelement, CMUT element and CMUT array is derived according to the theory of sound field. (4) in parallel plate capacitance model, static electric power plays an irreplaceable role in the work of CMUT, because the electrostatic force has nonlinearity, it makes the CMUT nonlinear in the launching process. In order to eliminate and suppress the nonlinearity of CMUT, remove the DC bias voltage to eliminate the harmonic component; use the change of the excitation signal type, select the bipolar pulse according to the power spectrum suppression effect, use the linear and nonlinear compensation method to eliminate the two harmonic components according to the angle formula. (5) according to the actual application, this paper studies C The packaging method of MUT chip is designed and the package structure is designed. According to the acoustic theory, the material selection, structure parameters, stress size, sound permeability coefficient of the CMUT enclosure are analyzed in detail, and the CMUT's watertight encapsulation is finally realized. The CMUT experimental system is built to test the designed CMUT performance, receiving performance, directivity and bandwidth performance. The results show that the designed CMUT array can meet the requirements of underwater imaging.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB552

【參考文獻(xiàn)】

相關(guān)期刊論文 前8條

1 王朝杰;王紅亮;段培盛;陳一波;胡曉峰;;電容式微機(jī)械超聲傳感器(CMUT)聲場特性分析[J];儀表技術(shù)與傳感器;2016年12期

2 施義茂;張建寰;陳仲懷;張陳濤;;超聲相控陣探頭聲場優(yōu)化設(shè)計仿真[J];廈門大學(xué)學(xué)報(自然科學(xué)版);2013年03期

3 Ting Yu;Wenchao Zhou;Peng Xu;Fengqi Yu;Qin Qian;;THEORETICAL INVESTIGATION ON THE DYNAMIC PERFORMANCE OF CMUT FOR DESIGN OPTIMIZATION[J];Acta Mechanica Solida Sinica;2013年01期

4 張慧;宋光德;靳世久;官志堅(jiān);劉娟;;電容式微超聲傳感器的電極參數(shù)優(yōu)化設(shè)計[J];傳感技術(shù)學(xué)報;2010年07期

5 張慧;宋光德;官志堅(jiān);靳世久;;電容式微加工超聲傳感器結(jié)構(gòu)參數(shù)對性能的影響分析[J];傳感技術(shù)學(xué)報;2008年06期

6 馬青玉;馬勇;龔秀芬;章東;;生物組織成像中用反相位脈沖技術(shù)提高二次諧波信噪比的研究[J];應(yīng)用聲學(xué);2006年03期

7 田靜;汪承灝;徐聯(lián);喬東海;馬軍;郝震宏;魏建輝;;圓形振動膜硅微電容傳聲器[J];傳感技術(shù)學(xué)報;2006年05期

8 劉貴棟,沈毅,王艷;醫(yī)學(xué)超聲諧波成像技術(shù)研究進(jìn)展[J];哈爾濱工業(yè)大學(xué)學(xué)報;2004年05期

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