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1.
《Microwave Theory and Techniques》1975,23(1):85-92
Tapered velocity optical directional couplers showing 100-percent coupling have been fabricated in thin film form. A computer analysis shows that this type of coupler has greatly improved tolerance properties and does not, in particular, suffer from the severe tolerance restriction placed on velocity synchronism in conventional uniform couplers. 相似文献
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论述了熔锥型光纤耦合器的功率耦合理论,利用熔融拉锥法制得了3dB单模光纤耦合器。利用可调谐光源和光谱分析仪组成的光学测试系统,测试了熔锥型光纤耦合器的附加损耗、方向性与均匀性等光学性能。实验表明,该方法具有制作简单、较低的附加损耗和良好的方向性等优点。利用扫描电子显微镜观察了光纤耦合器的表面,发现在光纤耦合器的锥区存在微裂纹,并且拉伸速度越快,微裂纹越明显;在光纤耦合器的耦合区.光纤表面存在微小晶粒,且拉伸速度越慢,晶粒越粗大。 相似文献
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提出一种新的计算波导中场分布的方法。该方法基于有限元法(FEM),但采用人工透射边界,称之为有限元—人工透射边界法。并用渐变型声指向耦合器中表面声波导二维声场的计算实例说明该方法的实用性。 相似文献
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A new polymer composite thin film DMACB/PEK-c is reported. After poling of the film, the refractive indices n t and n n, that is the in-film-plane and the normal-to-film-plane refractive indices at 633 nm and the thickness d were determined using the quasi-waveguide m -line method. The results of measurement and calculation are: n t=1.657 3±0.001 7, n n=1.627 8±0.001 9, and d =1.427 8±0.003 1 μm. 相似文献
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分析了现有微波大功率测量装置中定向耦合器的优缺点,提出了一种新型的用于测量微波大功率信号的双定向耦合器。该双定向耦合器可以同时测量传输信号和耦合信号,在小孔耦合的基础上利用耦合片实现信号的耦合。耦合片安装在耦合头内部,耦合头作为一个独立的装置可以根据波导的尺寸调整安装位置。通过调节耦合片与波导的距离,祸合系数可以在一定范围内调节。利用HFSS进行了全波电磁场仿真,在ISM频段利用BJ-26波导验证了设计。该双定向耦合器体积小,易于装配,特别适用于大功率、双向测量的场合。 相似文献
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《Microwave Theory and Techniques》1981,29(2):96-101
A quasi-optical treatment is given for the dispersion relation and the group delay time of a magnetic wave guided by a YIG film having a weak linear taper in its thickness in the propagation direction of the guided magnetic wave. This treatment has 1) confirmed the intuitive results in which the local value of the thickness is used for the tapered film, 2) indicated the frequency regions of validity of the intuitive results, and 3) revealed interesting features of the wavenormal and ray directions inside a YIG film. 相似文献
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一种结构新颖的微波高功率定向耦合器 总被引:2,自引:0,他引:2
赵双领 《中国电子科学研究院学报》2009,4(2)
介绍一种结构新颖的微波高功率定向耦合器.该耦合器主线采用波导结构承受功率大,副线采用同轴结构对外连接方便,耦合机构采用单个圆孔实现,整个耦合器设计巧妙,结构简单,便于加工,易于装配,不用调试,指标好,可靠性高,特别适用于高功率、弱耦合、双向取样的场合. 相似文献
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传统四端口环形电桥耦合器的带宽只有10%到20%。为了获得更大的带宽,本文提出了一种改进型环形电桥耦
合器。通过额外增加一个隔离臂,新设计可以工作在整个W波段。在此基础上,本文在输入臂上加入了一个切角来改善
输出信号的隔离度。仿真研究结果表明,在75GHz 到110GHz,两输出信号的幅度不平衡度小于0.07dB,相位不平衡度小
于0.37 度。相比于未作切角处理的五端口环形电桥,新设计输出端口的隔离度在全频段内大于15.07dB。改进型耦合器
可以应用于W波段平衡调制器以及其他需要高输出隔离度的W波段功率分配系统。 相似文献
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针对短波自适应的跳频系统的天线接口——自动天线调谐器,提出了一种新颖可行的实施方案,这个方案采用先整体预调谐后再实时配置调配参数的方法从而大大改善了系统的性能。 相似文献
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圆形槽波导是一种新型的高功率毫米波、亚毫米波传输线.为了实现圆形槽波导之间的耦合,本文根据双槽波导的耦合机理,设计出了新型圆形槽波导走向耦合器,并计算了3dB圆形槽波导定向耦合器的频率特性. 相似文献
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在直接耦合式微波等离子体化学气相沉积金刚石膜装置的石英管反应腔加上磁镜场来更好地约束等离子体,使等离子体球成为“碟盘”状,提高了等离子体球的密度,在基本参数:反应压力2.5kPa、基片温度450℃、气体流量为Ar:40sccm、CH4:4sccm、Hz:60sccm不变的情况下,沉积面积直径由30mm增长到50mm,沉积速度由3.3μm/h增长到3.8μm/h,最大反射电流由15μA减小5μA。从而大大减少了在石英管壁和观察窗的沉积,有效利用微波能量电离出更多的活性基团沉积出高质量的(类)金刚石薄膜。 相似文献
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《Microwave Theory and Techniques》1980,28(3):235-238
Dispersion characteristics and radiation fields of an optical stripline waveguide radiating into free space are calculated. The waveguides are fabricated as multiple layers of differing dielectric materials. A top layer is etched to form a "cap" with an effective waveguide in a layer below the cap. Confinement of the fields to the waveguide is obtained in the vertical direction by dielectric discontinuities, while lateral confinement occurs because of spatial interference of a continuum of plane waves. The radiation field of the fundamental mode in a plane perpendicular to the waveguide layers is characterized by the layer widths and index discontinuities. Beamwidths of the fundamental mode in the plane parallel to the dielectric layers are developed in terms of the waveguide parameters. Values of these parameters which yield the best optical confinement under the stripe can be obtained. 相似文献
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采用熔融拉锥机,制作了具有均匀腰锥的H2敏传感器结构.拉锥长度设定为9 000 μm,拉锥速度0.1 mm/s,火焰高度为3 mm,拉锥后光纤的腰锥体处的均匀直径为30 μm.用电子束蒸发装置在拉锥光纤均匀锥段表面上生长H2敏Pd-Ag合金薄膜,镀膜室内真空度为2.9×10-3Pa,束流为0.35 A/s,沉积时间为10 min,膜厚为50 nm.设计了拉锥光纤H2敏传感器的实验装置,测试数据表明:Pd-Ag合金膜拉锥光纤H2敏传感器能够精确检测低于4%的H2浓度,适合于单点或多点分布式H2泄漏探测. 相似文献
19.
《Microwave and Wireless Components Letters, IEEE》2006,16(8):467-469
In this letter, we present a high performance 94-GHz millimeter-wave monolithic integrated circuit resistive mixer using a 70-nm metamorphic high electron mobility transistor (MHEMT) and micromachined ring coupler. A novel three-dimensional structure of a resistive mixer was proposed in this work, and the ring coupler with the surface micromachined dielectric-supported air-gap microstrip line structure was used for high local oscillator/radio frequency (LO–RF) isolation. Also, the LO–RF isolation was optimized through the simulation. The fabricated mixer has excellent LO–RF isolation, greater than 29 dB, in 2-GHz bandwidth of 93–95GHz. The good conversion loss of 8.9dB was measured at 94GHz. To our knowledge, compared to previously reported W-band mixers, the proposed MHEMT-based resistive mixer using a micromachined ring coupler has shown superior LO–RF isolation and conversion loss. 相似文献