共查询到19条相似文献,搜索用时 515 毫秒
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利用离散Green函数和有限元等方法对在64°YX-LiNbO3基片上铜短路金属栅阵中漏表面波的传播特性进行了理论研究。给出了不同厚度铜栅条引起的声表面波的色散关系和Coupling-of-Modes耦合模(COM)参数,对其色散特性进行了分析。为研制相应的声表面波器件提供理论支持。 相似文献
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声表面波理论是研究高性能声表面波器件的理论基础。耦合模理论因能正确、全面反映声表面波在压电材料上的传播特性得到广泛的重视。应用耦合模理论分析推导自行研制的Y型声表面波器件特性,并编制相应的软件包。应用该软件包计算Y型声表面波器件中心频率处的插入损耗(-12.6dB)与实验结果(约-13dB)相近,为声表面波器件提供一种有效的分析工具。 相似文献
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该文采用有限元法研究了基于ScAlN/6H-SiC结构的声表面波传播特性,并分析了4种激励条件下,压电材料厚度变化对ScAlN/6H-SiC结构中声表面波相速度和机电耦合系数的影响,通过改变电极厚度及金属化率再次对机电耦合系数进行优化。结果表明,IDT/ScAlN/6H-SiC结构的机电耦合系数可达到5.4%,对应的相速度为6.36 km/s,添加短路金属后,机电耦合系数值和相速度均有所提高,Metal/ScAlN/IDT/6H-SiC结构下优化的机电耦合系数和相速度分别为15.78%和7.33 km/s。 相似文献
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从一阶波动方程出发,详细推证了声表面波一阶耦合模微分方程,得到一个对任何声表面波器件普适的一阶耦合模方程,并阐明了方程中各参数及变量的物理意义,为精确分析和设计低损耗声表面波器件提供了最基础的理论依据。 相似文献
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In this paper, we use modified form of Bethe's small hole coupling theory to compute equivalent circuit parameters of an aperture coupled open resonator cavity. The open resonator cavity is composed of spherical mirrors of circular cross section. The cavity is coupled to a rectangular waveguide by means of a common hole in the mirror and the shorted end wall of the rectangular waveguide. Closed form expressions have been obtained for the equivalent circuit parameters. Experiments conducted in the W-band frequency range show good agreement with theory when an experimentally estimated correction to the transmission coefficient is applied for the thickness of the coupling holes 相似文献
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《Electron Devices, IEEE Transactions on》1978,25(3):369-374
The existence of a poly-Si control gate in an n-channel FAMOS makes the erase characteristics due to ultraviolet light (UVL) illumination different from those of conventional p-channel FAMOS's without control gates. The difference in erasing times between these two types of FAMOS has been explained by the attenuation of UVL in the control gate. However, it was clarified experimentally and analytically in n-channel FAMOS that UVL is propagated horizontally in an optical guide formed between the control gate and substrate and is then absorbed by the floating poly-Si gate. The absorbed UVL intensity in the floating gate through the proposed optical guide is calculated to be 109times stronger than that transmitted directly through the control gate whose thickness and absorption coefficient are assumed to be 3500 Å and 106cm-1, respectively. The proposed optical guide model is supported in experiments that erase time does not depend on the thickness of the control gate (2400- and 3600-Å devices are compared) and erase time in a device whose optical guides are open only on one side and the other side is covered by the control gate is about 2 times longer than that in a device which has two optical guides open on both sides. 相似文献
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Ruey Bing Hwang Cherng Chyi Hsiao 《Antennas and Propagation, IEEE Transactions on》2006,54(1):121-129
The phenomena of high frequency-selective transmission of a plane wave by a dielectric two-dimensional (2-D) periodic waveguide, comprising a uniform dielectric layer sandwiched by two finite thickness 2-D periodic structures served as the waveguide wall is described. This structure is termed a leaky parallel-plate-like waveguide because the waveguide walls are not perfect reflection mirrors. The scattering characteristics and dispersion relation, including the phase and attenuation constants, of the 2-D periodic waveguide are thoroughly analyzed with the modal transmission-line method and Floquet theory. The extraordinary open stopbands caused by the contra-flow coupling between a leaky parallel-plate-like waveguide and the leaky waves, which are generated by 2-D periodic structures (waveguide walls), are displayed in the form of the Brillouin diagram. The phase-match condition is used to verify the resonant coupling between the incident plane wave and the leaky parallel-plate-like waveguide modes. Specifically, the transmission peak frequencies are accurately predicted. 相似文献
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为了掌握长程表面等离子体波的共振角度、共振峰半峰全宽以及衰减峰深度等重要特性,采用棱镜耦合激发介质-金属薄膜-介质对称结构中的长程表面等离子体波,研究了金属膜材料、厚度、介质折射率及介质厚度等参量变化时对长程表面等离子体波特性的影响。结果表明,实验中激发的长程表面等离子体波的衰减峰半峰全宽比传统的窄1~2个数量级;当介质膜厚度为500nm和1300nm时,激发的表面等离子体波的衰减深度只有薄膜厚度为700nm和1000nm时的1/2左右;随着介质膜厚度的增加,半峰全宽减小,金属膜越薄,衰减深度越深,衰减峰的半峰全宽值越小;介质膜折射率的改变对于半峰全宽的影响不明显;金属膜参量的变化将改变共振峰的位置。该研究为长程表面等离子体波的激发及应用于传感领域提供了有效依据,有利于其在波导和生物传感等方面的应用。 相似文献
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为掌握钻柱內孔微波传输的最佳频点,获取微波信道的衰减规律及有效传输距离,将钻柱内孔视为超长不规则有耗圆波导,采用微波耦合理论计算了其微波最佳传输频点,分析了信道中的微波模式。采用微波传输等效电路法建立了信道模型,研究并建立了钻柱内孔微波信道信号衰减规律模型。同时针对超长钻柱,提出单位长度平均功率损耗系数对有效传输距离进行简化分析。研究结果表明,钻柱内孔沿轴向存在内径渐变段和突变点,微波传输存在大量反射过程,信道的阻抗变化是影响传输质量的主要因素。建立的衰减模型比仅考虑表面电阻涡流损耗的模型更准确,更具有现场指导意义。 相似文献
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We have found a simple method which gives the attenuation coefficient in the transmission-line model for a piezoelectric resonator operating in a thickness mode. This attenuation coefficient has been determined in terms of the thickness, static capacitance, piezoelectric coupling constant, resonance frequency and the additional value of the maximum input resistance. 相似文献
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Chi Zhang Zhao Hua Zhang Xiang Yang Tao Zhou Chang Bao Han Zhong Lin Wang 《Advanced functional materials》2016,26(15):2554-2560
Tribotronics is a new field developed by coupling triboelectricity and semiconductor, which can drive triboelectric‐charge‐controlled optoelectronic devices by further introducing optoelectronics. In this paper, a tribotronic phototransistor (TPT) is proposed by coupling a field‐effect phototransistor and a triboelectric nanogenerator (TENG), in which the contact‐induced inner gate voltage by the mobile frictional layer is used for modulating the photodetection characteristics of the TPT. Based on the TPT, alternatively, a coupled energy‐harvester (CEH) is fabricated for simultaneously scavenging solar and wind energies, in which the output voltage on the external resistance from the wind driven TENG is used as the gate voltage of the TPT for enhancing the solar energy conversion. As the wind speed increases, the photovoltaic characteristics of the CEH including the short‐circuit current, open‐circuit voltage, and maximal output power have been greatly enhanced. This work has greatly expanded the functionality of tribotronics in photodetection and energy harvesting, and provided a potential solution for highly efficient harvesting and utilizing multitype energy. 相似文献