共查询到18条相似文献,搜索用时 375 毫秒
1.
为满足日渐增加的电磁屏蔽要求,设计了一种透明基材上柔版印刷电磁屏蔽用金属网栅,研究了影响金属网栅透光率与电磁屏蔽特性的主要因素。首先从理论分析入手,计算并分析金属网栅结构参数(线宽、周期、占空比)等对透明导电金属网栅透光率及电磁屏蔽效能的影响;接下来利用柔版印刷方式制备周期为300、400 m线宽为20、30、40 m的金属网栅,测试了在7、10、13 GHz3个频点处电磁屏蔽效能以及300~1 000 nm波段的紫外-可见透过率。测试与分析结果表明:金属网栅在紫外-可见光波段透过率在70%~80%之间,且随周期/线宽增大而分别增大/减小,电磁屏蔽效能最高达到了15 dB以上。结果显示,网栅的光电特性是矛盾的,线宽与周期越小电磁屏蔽效果越好。 相似文献
2.
3.
针对电磁辐射对日常生活、社会安全以及军事等领域所造成的危害,研究透红外/可见光学窗电磁波屏蔽技术。为降低传统金属网栅可见和红外波透过率低的问题,提出在光学窗上制作由ITO、SnO2等氧化物膜构成透明导电网栅。从理论分析入手分析导电网栅线宽、周期对光电特性的影响,利用镀膜、光刻及化学腐蚀方法制备线宽和周期不等的ITO膜网栅,并将其结果与金属网栅进行对比分析得出结论:红外透过率方面,ITO膜网栅大于金属网栅,并且相差较多,可达10%以上;而屏蔽效率方面ITO膜网栅小于金属网栅,但相差很小,最大仅2~3 dB。因此,透明导电膜网栅代替金属网栅用于解决红外透过率与屏蔽效率的矛盾实用价值更高。 相似文献
4.
通过理论计算分析了金属网栅的电磁屏蔽特性与红外透过率之间的关系,发现金属网栅的电学特性与光学特性是相背离的。为满足镀金属网栅后光学镜片的透过率降幅小于等于5%、屏蔽效能大于30 dB (频率范围为14 kHz~18 GHz)的要求,首先通过理论计算选用线宽为10 μm、周期单元的长度和宽度均为500 μm、膜层厚度为1 μm的金属网栅(Ni-Ag)。然后采用直流磁控溅射镀制技术在直径为100 mm的硫化锌基片表面成膜。经过曝光、显影、坚膜、腐蚀、剥离等工艺,获得了镀Ni-Ag频率选择表面(Frequency Selective Surface, FSS)网栅的红外窗口样片。最后对红外窗口样片进行了透过率和屏蔽效能测试。测试结果满足设计要求。该计算数据可用于预估光学窗口的电磁屏蔽性能,为后续的设计工作提供参考。 相似文献
5.
在线宽、周期不变(相同透光率)的前提下,增加网栅厚度才能降低网栅的表面电阻,从而进一步提高球面网栅的电磁屏蔽性能。首先推导了网栅厚度、表面电阻和电磁屏蔽效能之间的数学关系,接着开展了膜层增厚的化学镀镍工艺实验。实验结果表明:球面铜网栅上可以得到厚度均匀、结合力牢固的镍磷合金镀层,面电阻由50Ω降至15Ω。经天线法测试,在200 MHz~18 GHz波段,镀镍球面金属网栅膜屏蔽效能平均达到46 dB,比未镀镍前平均提高了8 dB,而球面网栅试件镀镍前后,在400~900 nm波段透过率均为88%。镀镍前后透过率基本相同时,镀后表面电阻迅速降低,电磁屏蔽效能得到了显著提高。 相似文献
6.
镀制了金属网栅的蓝宝石光学窗口兼具激光红外双波段高透过性和微波波段优良电磁屏蔽特性。为了抑制电磁屏蔽光学窗口内金属网栅衍射产生的杂散光,提升光学系统的探测距离和分辨率,本文设计了一种具有随机圆环结构的金属网栅电磁屏蔽光学窗口,并对金属网栅电磁屏蔽光学窗口光学波段的衍射特性和雷达波段的电磁屏蔽效能进行了建模、仿真和测试。结果显示,本文设计的随机圆环金属网栅电磁屏蔽光窗具有优良的衍射均匀性,光学透过率满足使用要求,1~18GHz频段范围屏蔽效能优于20dB,具有优良的综合性能,有望应用在先进光电探测装备中。 相似文献
7.
8.
9.
利用电沉积法制备磁屏蔽薄膜,不仅可以精确控制沉积膜的化学成分和厚度,而且可以在复杂几何形状的表面上形成薄膜。通过电沉积装置制备了铁镍-铜-铁镍多层复合磁屏蔽薄膜,并探究了磁场强度、厚度、高温环境对磁屏蔽薄膜屏蔽效能的影响。实验结果表明,50 μm和100 μm样品的屏蔽效能随磁场强度的增大而增大,200 μm的屏蔽效能则是先增大后降低;在4~16 Oe磁场中,厚度越大,薄膜屏蔽效果越好;100 ℃的温度会降低所有厚度的磁屏蔽薄膜的屏蔽效能。 相似文献
10.
11.
Light transmittance and the Rf shielding effectiveness of a gold film on a glass substrate is investigated. The dependence of the transmittance of visible light upon the thickness or surface resistance of a gold film on a glass substrate is determined numerically by the optical properties of the gold film and glass substrate. The Rf shielding effectiveness produced in the far field over the frequency range of 100 MHz to 30 GHz by the gold film is calculated and compared with experimental data. An optimum condition is established between the light transmittance and the shielding effectiveness. The results are applicable to any transparent glass coated with any thin metallic film. 相似文献
12.
RF shielding effectiveness and light transmittance of acopper or silver film coating on a plastic substrate is investigated. The dependence of the RF shielding effectiveness upon the surface resistance or thickness of a copper or silver film coating on a plastic substrate is calculated numerically by means of multireflection transmission-line theory over the frequency range of 100 MHz to 30 GHz. The light transmansmittance is determined by using the optical properties of the copper or silver film and plastic substrate. An optimum condition between the RF shielding effectiveness and the light transmittance is established for the copper or silver film coating on a plastic substrate. 相似文献
13.
Sarto M.S. Voti R.L. Sarto F. Larciprete M.C. 《Electromagnetic Compatibility, IEEE Transactions on》2005,47(3):602-611
New nanolayered coatings are designed and deposited on flexible plastic substrate having the thickness of 100 /spl mu/m, in order to realize lightweight ultrathin transparent shielding foils. The structure of the coating is optimized considering three figures of merit: the average transmittance in the visible range for normal incidence, the normalized average transmittance for oblique incidence at 550 nm, and the transmittance quality factor. The nanotechnology exploited for the deposition of the transparent metals is the dual ion beam sputtering. Tests of durability, optical transmission, and shielding effectiveness demonstrate that the film has a high adhesion under mechanical solicitation, high resistance against aging, peak transmittance in the visible range higher than 70%, omnidirectional properties in the range 0/spl deg/-60/spl deg/, and shielding effectiveness of 40 dB up to 6 GHz. 相似文献
14.
15.
16.
以圆形截面坑道为简化模型,运用旋转对称体时域有限差分法将三维问题转化为二维问题处理,计算了地下防护工程口部金属门对高功率微波、超宽带电磁脉冲的屏蔽效能,分析了门缝大小、门框嵌入岩土介质深度对屏蔽效能的影响,确定了场泄漏的主要途径.计算结果表明,门对坑道中不同的传输波模具有不同的屏蔽效能;泄漏场主要是通过门框的绕射进入工程内部,门缝的泄漏较小,门缝大小以及门框嵌入岩土介质的深度对屏蔽效能的影响是次要的;另外,通过门的泄漏场在工程内部迅速衰减;HPM的载频越高,UWB的脉宽越窄,门的屏蔽效能越好.最后对数值计算结果和实验测得数据进行了比较,二者吻合较好,证实了数值计算的有效性. 相似文献
17.
18.
Ultrathin Flexible Graphene Film: An Excellent Thermal Conducting Material with Efficient EMI Shielding 下载免费PDF全文
As the portable device hardware has been increasing at a noticeable rate, ultrathin thermal conducting materials (TCMs) with the combination of high thermal conductivity and excellent electromagnetic interface (EMI) shielding performance, which are used to efficiently dissipate heat and minimize EMI problems generated from electronic components (such as high speed processors), are urgently needed. In this work, graphene oxide (GO) films are fabricated by direct evaporation of GO suspension under mild heating, and ultrathin graphite‐like graphene films are produced by graphitizing GO films. Further investigation demonstrates that the resulting graphene film with only ≈8.4 μm in thickness not only possesses excellent EMI shielding effectiveness of ≈20 dB and high in‐plane thermal conductivity of ≈1100 W m‐1 K‐1, but also shows excellent mechanical flexibility and structure integrity during bending, indicating that the graphitization of GO film could be considered as a new alternative way to produce excellent TCMs with efficient EMI shielding. 相似文献