共查询到19条相似文献,搜索用时 109 毫秒
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介电常数是材料的重要特性之一,采用互补开口谐振环微带传感器实现了不同厚度待测物质介电常数的无损测量。方形互补开口谐振环蚀刻在微带线接地平面上,与微带线耦合实现谐振,分析了谐振器的等效电路,讨论了介电常数与谐振频率之间的关系。通过有限元分析,谐振频率的负二次方与待测物质的介电常数实部值存在线性关系,且线性关系受待测物质的厚度影响;介电常数的虚部值对谐振频率的影响可忽略不计;最终建立了介电常数实部值与谐振频率和样本厚度之间的数学解析式。实验测试结果表明,当待测样品的厚度大于2 mm时,实部介电常数的相对测量误差小于3.5%。 相似文献
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固态材料介电常数的测量常采用双端口传感器,但传感器尺寸较大,针对此问题,设计了一款单端口特性的射频传感器,尺寸仅为30×40 mm。射频传感器采用开口谐振环结构,选用介电常数为4.4的FR4材料作为传感器基板,厚度为1 mm。首先使用电子设计自动化软件ADS设计了传感器,并对加载不同介电常数模型的传感器进行仿真,以得到不同介电常数下的回波损耗S11;随后使用MATLAB对S11谐振频率进行处理,得到待测样品厚度为0.8 mm的拟合公式。最后,将实测数据代入拟合公式得到材料介电常数的测量值,并与样品介电常数标准值比较。实验结果表明,使用该射频传感器测量Rogers 5880得到的介电常数为2.18,误差为0.91 %;测量FR4得到的介电常数为4.32,误差为1.82 %。因此,射频传感器可以用于固态材料介电常数的精准测量。 相似文献
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针对海洋沉积物中天然气水合物饱和度评价需求,提出了基于分段涂层TDR探针的沉积物介电常数和电导率同步测量新方法。针对无涂层探针、全涂层探针以及分段涂层探针分别建立了模拟TDR测量响应的有限元数值模型,仿真研究了涂层参数对介电常数和电导率测量性能的影响规律,继而应用于含水合物多孔介质的测量并对误差进行了分析与校正。研究结果表明:探针涂层的厚度和介电常数直接影响采集电压信号的衰减程度,因此需根据被测介质的电学性质对其进行优化设计;在涂层厚度和介电常数已确定的条件下,通过改变涂层间隙长度可以调节探针所适用的电导率测量范围;当测量非均匀介质时,可以通过增加涂层间隙的个数来提高电导率测量的准确度;采用分段涂层探针测量含水合物多孔介质的介电常数和电导率时,需要对涂层引起的误差进行校正。 相似文献
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为使标签能够克服阅读方向固定的限制、增强标签的环境适应性,从而可靠适用于标签方向不清楚或不固定的应用领域,设计了一种结构完全对称的、基于1/4圆环贴片谐振体阵列的无芯片射频识别(RFID)标签。利用基本谐振单元在特定频点的谐振特性,以不同物理参数谐振单元组合的方法产生特定的后向散射场频域特性,在(169π+10.4)mm2内可实现15 bits数据容量。仿真分析表明,标签雷达散射截面(RCS)曲线与标签结构相对应,谐振特征明显,谐振点明晰可辨,谐振点出现数目和位置与谐振单元存在的数目和位置一一对应,且标签对入射波入射方向、入射波极化以及观测点方向具有良好的不敏感性。 相似文献
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In this report, a free space frequency‐time‐domain technique is presented for characterizing the electrical properties and thickness of the sample using multiple reflections and fabry‐perot resonance phenomenon. The retrieval of constitutive electromagnetic parameters of the sample has been carried out by comparing the measured reflection coefficient data from the sample at two different incident angles. The relative permittivity as well as relative permeability along with the thickness of different samples viz., beryllia, silicon, and plexiglass have been evaluated with high accuracy in the frequency range 1 to 15 GHz. The method is also experimentally validated by successfully reconstructing the unknown material properties of two different samples. The unique advantage of this method lies in non‐requirement of any prior knowledge of the sample's thickness for measuring the complex relative dielectric constant as well as relative permeability of the sample. To determine the electromagnetic properties of the sample, the sole knowledge of reflection coefficient data are needed. Moreover, the method does not involve any additional measurement for the reference calibration. The simple, cost‐effective proposed scheme is quite useful in many applications like accurate determination of signal strength in indoor wireless communication, through wall imaging, food industry, and so on. 相似文献
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H. Blondeaux S. Bila D. Baillargeat S. Verdeyme P. Guillon A. Carlier E. Rogeaux 《国际射频与微波计算机辅助工程杂志》2000,10(6):333-341
A dielectric resonator filter is proposed for high‐speed data communication systems and for multilayer filter applications. The structure is composed of a partially metallized dielectric plate enclosed in a parallelepipedic cavity. This topology allows high integration in a planar‐type environment. The proper excitation is ensured by coplanar lines directly integrated on the dielectric resonator. This structure, easily manufactured, is suitable for high frequency‐filtering and power applications. In order to realize two‐ and four‐pole filters without tuning, some new coupling and frequency compensation techniques are presented. To compensate for a parasitic effect, a direct optimization method is combined applying a global electromagnetic (EM) analysis to describe the four‐pole filter. Some experiments are performed to verify the theoretical design. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 333–341, 2000. 相似文献
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One means of tuning the symmetric poles or modes, without perturbing the counter‐rotating family of poles or modes, of a planar disk resonator with top and bottom electric walls and a magnetic sidewall is to introduce a dielectric plug on its axis. The purpose of this paper is to investigate some intersections between the family of symmetric modes and that of pairs of degenerate counter‐rotating modes in such a resonator using a commercial FE solver. The relative dielectric constant of the outer region of the resonator has been restricted to 14.1 while that of the inner region has been allowed to vary between 25 and 500. The paper includes three typical mode charts on this type of resonator as well as some standing wave solutions using an FE solver. The work has application in the design of triple pole circulators and filters. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. 相似文献
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Composite right/left‐handed (CRLH) metamaterial unit cell whose ground‐plane is defected with a rectangular dielectric slot is used to develop a single and multi‐pole pole bandpass filter. The unit cell comprises of serially connected interdigital capacitors whose junction is connected to a short‐circuited inductive stub. By defecting the ground‐plane of the unit cell's structure with a dielectric slot, which is located immediately below the unit cell, enables substantial tuning of the filter's center frequency in the order of 26.5%. This is achieved with minimal effect on the unit cell's insertion and return‐loss performance including its selectivity. The filters were fabricated on conventional dielectric substrate and their performance measured to verify the design methodology. The proposed technique eases the trade‐off constraints and makes possible the realization of challenging filter specifications constituted from CRLH unit cells using distributed transmission‐lines. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:39–45, 2014. 相似文献
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对微波谐振腔微扰法检测基本理论和工作原理进行了论述,对微波作用的介电材料的电磁参数"介电常数"和"介电损耗"产生的相对变化进行了分析讨论,建立了烟支密度和湿度与谐振腔谐振曲线的频偏及半功率点带宽的数学表达式,设计制作了重入式微波谐振腔传感器.采用TM010谐振模,对烟支的密度和湿度进行了实时检测.以扫频法检测谐振腔空腔和有烟支状态下的幅频特性,获得谐振频率f、峰值功率p及半功率带宽ω.根据相关数学式得到了烟支的湿度和密度.该检测方法具有快速、连续、分辨力高、无污染和操作安全简便等优点.并且适用于工业现场在线测量. 相似文献
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A multilayered cascaded and polarization‐dependent frequency selective surface (FSS) exhibiting dual bandpass frequency response is proposed in this article. The FSS is composed of two metal‐based square patch layers in the two ends and one aperture type layer in the middle, separated by two dielectric substrates. The FSS exhibits bandpass response of third order with two transmission poles in the 5‐6 GHz band and one pole at 2.5 GHz. The passbands are separated well enough with a transmission zero at 3.5 GHz leading to significant out‐of‐band rejection. The structure is ultrathin with the thickness on the order of 0.01λ0 with respect to the lowest resonating frequency. It is shown with parametric studies how the poles can be tuned individually. Principle of operation of the FSS is explained with its equivalent circuit model. Transmission phase of the FSS varies linearly with frequency in the upper band. Simulation result is verified experimentally for the fabricated prototype. 相似文献
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提出了一种电磁谐振式微泵电感线圈组件的新制造方法,该方法在硅杯表面采用浓硼扩散区与镀金膜形成的欧姆接触电极作为内引线.我们设计了硅基电感的结构和相关的工艺流程,再利用Ansys有限元软件中的电磁分析模块模拟了电流与磁感应强度的关系、衬底涡流分布等,为平面电感的理论与实验的进一步比较分析提供了参考依据.我们在硅杯背面采用激光打孔得到了膜厚约为5 μm的硅膜,从而可以使衬底中的涡流大幅度减少、电感的Q值得到很大提高.本文提出的新制造方法采用了绝缘性能比SiO2好的Al2O3薄膜作为电感线圈与衬底之间的绝缘层.实验结果表明,本文设计的平面螺旋电感具有制造工艺简单、与IC工艺相兼容的优点,有广泛的应用前景. 相似文献
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研究了考虑粘弹性情形介电弹性体(DE)圆管的非线性动力学行为.利用弹簧-粘壶模型和不可压缩材料的neo-Hookean模型,建立了考虑粘弹性的介电弹性体圆管的动力学方程.采用小扰动方法,给出了瞬时固有频率的表达式,分析了特征时间、预拉伸以及圆管的厚度等参数对瞬时固有频率的影响规律.研究了受周期电压作用下的非线性振动特性,结果表明粘弹性会显著降低响应振幅,但不会影响准静态最终固有频率.在没有直流电压时,系统仅产生单一主共振,但当直流电压足够大时,会发生多频共振. 相似文献
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Baek‐woon Lee Young‐gu Ju Young In Hwang Hae‐yeon Lee Chi Woo Kim Jin Seok Lee Jun Hyung Souk 《Journal of the Society for Information Display》2009,17(2):151-157
Abstract— Two optical structures used for a bottom‐emitting white organic light‐emitting diode (OLED) is reported. An RGBW color system was employed because of its high efficiency. For red, green, and blue (RGB) subpixels, the cavity resonance was enhanced by the use of a dielectric mirror, and for the white (W) subpixel, the mirror was removed. The optical length of the cavities was controlled by two different ways: by the thickness of the dielectric filter on top of the mirror or by the angle of oblique emission. With both methods, active‐matrix OLEDs (AMOLEDs) that reproduced a color gamut exceeding 100% of the NTSC (National Television System Committee) standard were fabricated. More importantly, the transmission of a white OLED through R/G/B color filters was significantly higher (up to 50%) than that of a conventional structure not employing a mirror, while at the same time as the color gamut increased from ~75 to ~100% NTSC. 相似文献