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建立起高压介电测试装置和相应的数据处理方法。研究了PZT/P (VDF-T rFE) 和PT/P (VDF- rFE) 0-3型铁电复合物厚片介电系数的电场依赖性。对于陶瓷体积分数U> 0.3 的复合物, 介电系数随测试场强的升高明显增大。在U< 0.1 时, 可用M axw ell-Garnet t 方程拟合试验结果。B ruggeman 方程适合于低电场(< 1MV/m ) 下复合物介电系数的预测。通过L z 的变化, 用Yamada 模型可拟合复合物介电系数随电场变化的关系, 说明L z 是由复合物的组分维数、粒子形状以及粒子间静电相互作用所决定的参数。 相似文献
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详细研究了一种用于回旋管冷测的三段式同轴谐振腔模式激励器,该模式激励器利用同轴开放腔的选频选模特性将输入的W波段的波功率转换为TE6,2模式输出。基于缓变截面波导理论,研究了同轴谐振腔激励TE6,2模式的机理;求解了同轴波导中TE模式的特征根和不均匀弦方程并得到腔体谐振频率及Q值;分析了同轴腔内外半径对谐振频率的影响;给出了W波段高纯度TE6,2模谐振腔优化设计的参数;并用电磁仿真软件对其进行仿真计算,结果表明:该谐振腔的TE6,2模式纯度达到99.51%。 相似文献
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为了研究掺杂BarSr1-xTiO3介电薄膜材料的性能,采用阻抗分析仅等测试方法研究了微量元素钇对Sr0.5Ba0.5-yYyTiO3薄膜介电性能的影响。当Y元素的掺量为0-0.030mol时,相对介电常数εr和tanδ分别为74.2和0.067;最大介电常数温度点Tm(居里温度点)逐渐移向低温;在所测试频率范围内,Y元素的掺量为0.010、0.0150mol(Y2、Y3)时,εr、tanδ均能表现出较好的频散特性。采用XRD、TEM等测试方法分析了薄膜的结构特征。薄膜的矿物组成为四方钙钛矿结构,但Y的溶入改变了晶胞参数的c/a比,减小了薄膜的颗粒尺寸,提高了薄膜的致密度;晶粒的生长为取向一致和无取向生长两种方式。 相似文献
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提出了用幂基多项式拟合频响函数的几点技巧。运用幂基多项式和最小二乘法对频响函数拟合的计算公式进行了推导,得到了用于问题求解的线性代数方程组,为改善该方程组系统矩阵的条件数,对频率变量和系数矩阵进行了规范化处理;频率变量被规范化到0=-1的无量纲正实数区域,两个相关矩阵的每列模长被规范为1。然后用奇异值分解的方法求解该方程组,得到拟合频响函数所用的幂基多项式的系数。最后,根据幂基多项式的系数,求出系统的极点和留数,从而识别出系统的模糊态参数,文中给出了一个悬臂梁模拟算例,结果表明本文算法具有较好的计算精度。 相似文献
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研究了 SiO2-AlN复合材料介电性能随测试温度和测试频率变化的温度特性和频率特性 , 结果说明 :SiO2-AlN复合材料的极化机理表现为空间电荷极化。介电性能的温度特性说明 1350℃ 下热压烧结的 SiO2-AlN复合材料介电损耗随测试温度基本不变 ,表现了与 SiO2材料相一致的介 电稳定性 ,并基于 Debye弛豫方程作了分析。介电性能的频率特性说明极化弛豫普适关系适用于 SiO2-AlN复合材料。 相似文献
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针对飞机270 V直流电源供电特性测试系统的校准需求,结合GJB 5189-2003《飞机供电特性参数测试方法》等相关标准,完成测试系统的校准项目和校准方法研究,并基于LabVIEW平台编写校准程序,实现了标准信号的生成和采集;基于直接数据合成、宽带精密放大和宽带分压等技术研制了测试系统的校准装置,形成校准系统,实现了... 相似文献
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Microwave characterization of materials using dielectric resonators is based on measurements of the Q-factor of the resonator containing a sample under test and on the loss equation for the test structure. The loss equation contains geometrical factors, which are calculated assuming an ideal metallic cavity of the resonator. In this paper a rigorous analysis of cylindrical parallel plate dielectric resonators has been performed to assess the influence of the presence of coupling holes and cables on the unloaded Q-factor and resonant frequency. Calculations have been done for the TE011 mode resonators with differing cavity to dielectric diameter ratio, conductivity of the cavity material, loss tangent and relative permittivity of the dielectric rod, position of the coupling loops and size of the coupling cables. Results have shown that Qo-factors calculated for real resonators were smaller than Qo-factors for ideal resonators. Also this paper presents a brief history of analysis of dielectric resonators. 相似文献
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Microwave characterization of materials using dielectric resonators is based on measurements of the Q-factor of the resonator containing a sample under test and on the loss equation for the test structure. The loss equation contains geometrical factors, which are calculated assuming an ideal metallic cavity of the resonator. In this paper a rigorous analysis of cylindrical parallel plate dielectric resonators has been performed to assess the influence of the presence of coupling holes and cables on the unloaded Q-factor and resonant frequency. Calculations have been done for the TE011 mode resonators with differing cavity to dielectric diameter ratio, conductivity of the cavity material, loss tangent and relative permittivity of the dielectric rod, position of the coupling loops and size of the coupling cables. Results have shown that Qo-factors calculated for real resonators were smaller than Qo-factors for ideal resonators. Also this paper presents a brief history of analysis of dielectric resonators. 相似文献
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本文讨论了行波管夹持杆微波性能的测试技术。采用模式识别技术,实现了在不同频段用一测试腔对夹持杆介电参数的测量。 相似文献
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微波介质谐振器介电参数的测量 总被引:6,自引:0,他引:6
本文讨论了微波介质谐振器介电参数测试技术。用研制的测试装置对多个介质样品进行了实测,结果表明,本文的分析与实际值是吻合的。该测试技术可对微波介质谐振器的复介电常数进行迅速、准确、可靠、宽频带、无损伤、自动化和批量检测,具有较强的实用性。 相似文献
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Fuli Zhang Chang Li Yuancheng Fan Ruisheng Yang Nian‐Hai Shen Quanhong Fu Weihong Zhang Qian Zhao Ji Zhou Thomas Koschny Costas M. Soukoulis 《Advanced materials (Deerfield Beach, Fla.)》2019,31(39)
Artificially structured metamaterials with metallic or dielectric inclusions are extensively studied for exotic light manipulations via controlling the local‐resonant modes in the microstructures. The coupling between these resonant modes has drawn growing interest in recent years due to the advanced functional metamaterial making the microstructures more and more complex. Here, the suppression of magnetic resonance of a dielectric cuboid, an analogue to the scattering cancellation effect or radiation control system, realized with an exterior cloaking in a hybrid metamaterial system, is demonstrated. Furthermore, the significant modulation of the absorption of the dielectric resonator in the hybrid metamaterial is also demonstrated. The physical insight of the experimental results is well illuminated with a classical double‐harmonic‐oscillator model, from which it is revealed that the complex coupling, i.e., the phase of coupling coefficient, plays a crucial role in the overall response of the metal–dielectric hybrid system. The proposed design strategy is anticipated to form a more straightforward and efficient paradigm for practical applications based on radiation control via versatile mode couplings. 相似文献
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We report on the magnetodielectric characterization of orthorhombic (001) oriented YMnO3 thin films grown by PLD on Nb-doped SrTiO3. Detailed temperature, magnetic field and frequency dependent measurements are used to determine dielectric and magnetodielectric response and to analyse its origin. A dielectric peak below the Néel temperature is observed. We show that this peak signals a magnetoelectric coupling as inferred from a magnetocapacitance of about 2% at 8 T and 25 K. A careful analysis of the impedance spectroscopy allows concluding that both the dielectric peak and the measured magnetocapacitance are intrinsic properties of YMnO3. At higher temperatures (> 200 K) another dielectric feature (a strong frequency dependency and a peak in the dielectric losses) is observed, which is ascribed to the Maxwell-Wagner behaviour and thus it is not a genuine response of stoichiometric YMnO3. 相似文献
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倪尔瑚 《材料科学与工程学报》1993,(2)
本文简要介绍自1970年以来得到重大发展的微波介质谐振器陶瓷,指出某些基本规律、特性及研究发展动向,也讨论了材料特征电参数间的相互依存关系。最后举例说明介质谐振器在蜂巢式便携电话中的双工器及稳频振荡器方面的应用。 相似文献
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Xiangyi Fang Linton D. Walker C. Collins B. 《IEEE transactions on instrumentation and measurement》2004,53(6):1473-1478
The split cylinder resonator method is improved for nondestructive and accurate measurement for low permittivity materials at multiple frequency points. The dielectric constants of flat substrate materials are calculated based on a rigorous mode match analysis of the TE/sub 011/ mode. The loss tangent is also approximately calculated. The dielectric properties of two commercial substrates have been measured at multiple frequencies. The results demonstrate that this technology is capable of accurately characterizing the dielectric properties of flat substrate materials versus frequency in a nondestructive way. 相似文献