共查询到19条相似文献,搜索用时 265 毫秒
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提出了基于时域有限差分法(FDTD)对一维压电换能器的机电耦合现象进行数值分析的新方法.利用时域有限差分法理论对压电材料的控制方程、牛顿方程在空间和时间上进行了心差分离散化,并首次提出了压电换能器的收发电压信号和压电控制方程间关系的迭代差分方程,借助这些差分方程,从而能直接给出压电换能器声场传播的时域信息.利用此法分析了压电换能器匹配层厚度对接受电压波形的影响,并得到了其质点速度和质点应力传播的时空分布图.另外,还提出了利用Prony法替代FFT法,从而利用更短时域响应来得到压电换能器的频域特性.仿真结果表明,提出的模型能有效分析多层压电换能器的稳态和瞬态激励响应的传播特性. 相似文献
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报道了一种空气隙型S波段薄膜体声波谐振器,该谐振器采用一维Mason模型进行仿真,电极材料选用Mo,压电薄膜材料选用AlN,通过对AlN薄膜制备条件的优化,得到了半高宽为3.32°的AlN压电薄膜,并用于研制薄膜体声波谐振器。测试结果表明,其串联谐振频率和并联谐振频率分别为2 185 MHz和2 217 MHz,有效机电耦合系数(kt2)为3.56%,在串联谐振频率和并联谐振频率处的品质因数(Q)值分别为1 571.89和586.62,kt2Q达到了55.96。根据实测结果提取了MBVD模型的参数,并将实测结果与MBVD拟合结果进行了对比,两者吻合得很好。 相似文献
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介绍了一种薄膜体声波谐振器和它的制备流程.该谐振器采用氧化锌压电薄膜作为压电材料,通过从硅片背部体刻蚀硅衬底的方法得到谐振器的支持层.为了避免残余应力引起的支持层起皱现象,采用氮化硅/二氧化硅/氮化硅复合膜作为支持层.采用直流磁控溅射的方法制备氧化锌压电薄膜,X射线衍射结果显示,氧化锌压电薄膜C轴择优取向明显,衍射峰半高宽为0.227 3°,显示出较好的结晶质量;扫描电镜观察到氧化锌垂直于薄膜表面的柱形晶粒结构,薄膜表面平整、致密.采用HP8753D射频网络分析仪对该薄膜体声波谐振器样品进行了测试,结果表明,谐振器具有明显的厚度伸缩振动模式,其基频在750 MHz左右,二次谐频在1.5 GHz左右.进一步提高氧化锌压电薄膜的性能,该谐振器可用于射频振荡源和射频前端滤波器中. 相似文献
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该文介绍了一种采用智能截割(Smart Cut~(TM))技术制备的单晶铌酸锂(LiNbO_3)薄膜体声波谐振器。采用COMSOL有限元仿真软件从材料和结构两方面对LiNbO_3薄膜体声波谐振器进行优化设计,以实现高机电耦合系数,并通过Smart Cut~(TM)工艺方法制备了高性能Z切-LiNbO_3单晶薄膜作为谐振器的压电层,最终得到LiNbO_3薄膜体声波谐振器的谐振频率为3 847.5 MHz,反谐振频率为3 986.25 MHz,插入损耗为1.81 dB,谐振器有效机电耦合系数达到8.3%。 相似文献
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针对未来移动通信对射频前端器件提出的多频率、高集成新要求,开展了兼具声表面波(SAW)谐振器和薄膜体声波谐振器(FBAR)技术特点的新型横向激励兰姆波谐振器研究。该文介绍了基于c 轴择优取向氮化铝(AlN)压电薄膜的C波段横向激励薄膜体声波谐振器(XBAR)的结构设计、参数优化和制备方法,并进行了工艺验证。通过剥离和刻蚀等步骤制备了谐振频率4.464 GHz、品质因数3 039、品质因数与频率之积(f ×Q )达到1.56×1013 GHz、面积小于0.12 mm2 的低杂波XBAR谐振器,并仿真分析了其用于射频滤波器的可行性。该研究为进一步研制多频率、高集成的小型化XBAR滤波器组件提供了有效的设计技术和工艺技术支撑。 相似文献
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为了能有效解决柔性基底体声波谐振器热稳定性不足及功率容量不足等问题,该文提出了一种新型的基于柔性基底的薄膜体声波谐振器。该谐振器的硅衬底上开设有一定数量的垂直上凸型结构,该结构既能有效抑制寄生模量,又能减小器件最高稳态温度和最大热应力。通过有限元分析软件Comsol Multiphics对谐振器进行仿真,结果表明,器件每增加一个上凸型结构,其最高稳态温度下降了4 ℃,最大热应力下降了1×104 GPa。与以往的柔性基底薄膜体声波谐振器相比,它具有更好的热传导能力和热应力稳定性。 相似文献
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Zhengwei Du Ke Gong Jeffrey S. Fu 《Journal of Infrared, Millimeter and Terahertz Waves》1999,20(4):661-668
The stability criterion for the numerical solutions of two-dimensional Maxwell's equations obtained by the method of difference-Thompson transformation (DTTR) combined with the finite difference time domain (FDTD) method is obtained for the first time. 相似文献
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基于半隐式的Crank-Nicolson差分格式给出了一种无条件稳定时城有限差分方法。和传统FDTD法中采用的显式差分格式不同,对Maxwell方程组采用半隐式差分格式,在时间和空间上仍然是二阶精确的。但时间步长不再受稳定性条件的限制,只需考虑数值色散误差对其取值的制约。利用分裂场完全匹配层吸收边界截断计算空间,为保证PML空间的无条件稳定性,其方程也采用半隐式差分格式。数值结果表明相同条件下US-FDTD方法与传统FDTD方法的计算精度是相同的,而且在增大时间步长时US-FDTD方法是稳定的和收敛的。可以预见US-FDTD方法在模拟具有电小结构问题时具有实际意义。 相似文献
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Ki-Wone Seo Saehoon Ju Hyeongdong Kim 《Electron Device Letters, IEEE》2002,23(6):327-329
The finite-difference time-domain (FDTD) technique has been applied to analyze electromechanical phenomena of thin-film bulk acoustic wave resonators (TFBARs) for the first time. To simulate several TFBARs that have one-dimensional (1-D) piezoelectric material variations, current-driven governing equations are discretized in spatial and temporal domain. The impedance characteristics are obtained by the proposed method and compared with the analytical solutions of the 1-D Mason model. Also, the values of lumped elements for the Butterworth Van Dyke (BVD) equivalent circuit are extracted. The results show that the proposed scheme has the potential to analyze the characteristics of arbitrary piezoelectric material embedded structures 相似文献
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Wei Shao Bing-Zhong Wang Zhong-Jun Yu 《Electromagnetic Compatibility, IEEE Transactions on》2006,48(1):10-18
A hybrid time-domain numerical method based on finite-difference technique and moment method is proposed. Starting from Maxwell's differential equations, our method uses Yee's finite difference scheme in the space domain, but does not utilize the customary explicit leap-frog time scheme. Instead, in the time domain, the fields are expanded in a series of basis functions and treated by a moment method procedure. By choosing appropriate basis functions and testing functions, the conventional finite-difference time-domain (FDTD) formulation and the order-marching unconditionally stable FDTD scheme can be derived from our method as two special cases. Finally, we use triangle basis functions and Galerkin's testing procedure to get an implicit formulation. To verify the accuracy and efficiency of the new formulation, we compare the results with the FDTD method. Our method improves computational efficiency notably, especially for multiscale problems with fine geometric structures, which is restricted by stability constrain in the FDTD method. 相似文献
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A new 2-D FDTD method applied to scattering by infinite objects with oblique incidence 总被引:1,自引:0,他引:1
Yun Yi Bin Chen Da-Gang Fang Bi-Hua Zhou 《Electromagnetic Compatibility, IEEE Transactions on》2005,47(4):756-762
A new two-dimensional (2-D) finite-difference time domain (FDTD) method applied to scattering by infinite objects with oblique incidence is proposed. 2-D Maxwell's equations, differential equations, and perfectly matched layer (PML) absorbing boundary conditions (ABC) are derived. The incident wave, computed by the 1-D FDTD method, is set on the connecting boundary. The accuracy and the efficiency of the proposed method have been verified by comparing the results of the split-field periodic FDTD method, the sine-cosine method, and the transmission line theory method with the proposed method. 相似文献
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Yan Qing Zeng Qing Huo Liu 《Geoscience and Remote Sensing, IEEE Transactions on》2001,39(6):1165-1173
Acoustic waves can be a viable tool for the detection and identification of land mines, unexplored ordnance (UXO), and other buried objects. Design of acoustic instruments and interpretation and processing of acoustic measurements call for accurate numerical models to simulate acoustic wave propagation in a heterogeneous soil with buried objects. Compared with the traditional seismic exploration, high attenuation is unfortunately ubiquitous for shallow surface acoustic measurements because of the loose soil and the fluid in its pore space. To adequately model such acoustic attenuation, we propose a comprehensive multidimensional finite-difference time-domain (FDTD) model to simulate the acoustic wave interactions with land mines and soils based on the Biot theory for poroelastic media. For the truncation of the computational domain, we use the perfectly matched layer (PML). The method is validated by comparison with analytical solutions. Unlike the pure elastic wave model, this efficient PML-FDTD model for poroelastic media incorporates the interactions of waves and the fluid-saturated pore space. Several typical land mine detection measurements are simulated to illustrate the application 相似文献
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廖成 《红外与毫米波学报》2001,20(6):442-446
利用Thompson变换在任意形状的散射体外部产生共形的外部计算网络,并使FDTD计算区域的截断边界与散射体边界形状完全一致,时域不变性测试方程(MEI)方法被作为该截断边界上的局域吸收边界条件,从而大大压缩了FDTD的计算空间。数值试验结果证实,该方法可在不降低计算精度的前提下减少计算机内存需求。 相似文献
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Finite difference time domain (FDTD) analysis has been successfully formulated for solving diffusion equation in biological tissues. Time-dependent diffusion equations are approximated by FDTD equations by assigning diffuse photon fluence rates and radiant flux defined in the diffusion equations to Yee meshes. At the boundary between scattering and no scattering material, FDTD equation including only fluence rate has been derived, which make it possible to calculate the fluence rate at the boundary. The formulation is useful to solve diffusion equations by iterative algebraic calculations in scattering media with inhomogeneous optical properties. The conditions to give stabilities for numerical solutions have been become clear in terms of scattering coefficients and mean cosine of scattering angles. Using the formulation, the reflectance of three-layered slabs containing a clear layer have been calculated. As a result, it has been found that absorption loss changes of the highly scattering medium beyond the clear layer are estimated from the time profiles of the reflectance. 相似文献