共查询到20条相似文献,搜索用时 125 毫秒
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王玉林 《固体电子学研究与进展》2006,26(4):481-484
介绍声表面波锥形叉指换能器的基本原理,采用折线电极锥形叉指换能器制作的TD-SCDMA制式用96MHz宽带滤波器,1dB带宽4.8MHz,15dB抑制小于6.4MHz,插入衰耗约12dB,封装为SMD(13.3mm×6.5mm)。 相似文献
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本文主要介绍了一种工作于2~6GHz,3dB带宽大于200MHz的磁调谐带通滤波器的设计原理及方法,这种宽带宽的磁调谐带通滤波器利用多晶铁氧体材料制作,采用了新的耦合结构,为实现宽频带调谐,采用了与传统YIG滤波器磁路结构不同,具有不同磁场梯度的新型磁路结构设计.并通过实验验证了设计的正确性,实验结果表明该种结构设计的磁调谐带通滤波器,不仅工作频段宽,与一般的YIG带通滤波器相比具有3dB带宽,调谐方便的优点,拓展了磁调谐带通滤波器的应用. 相似文献
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基于UWB 系统的巴伦滤波器组合器件 总被引:1,自引:0,他引:1
UWB 超宽带系统的快速发展对滤波器和巴伦的带宽、损耗提出了新的要求。平衡滤波器能够实现良好的匹配和滤波特性,插入损耗较小,但仅适用于窄带情况;表贴巴伦和滤波器同时使用时不仅占用较大面积,彼此间的干扰会降低系统性能。本文采用补偿法,将多层LC 滤波器和宽带Marchand 巴伦通过耦合电容连接制作在同一LTCC 基板内,减小面积的同时,缺点互补,巴伦改善了滤波器的衰减特性,滤波器改善了巴伦的匹配特性,适用于UWB 宽带应用。根据这一思路制作的巴伦-滤波器的中心频率为7.65GHz,带宽为1GHz,幅度失配≤0.2dB,相位失配≤4.5°,5GHz 处带外衰减≥60dB,9GHz 处带外衰减≥40dB,元件尺寸为7mm*3mm*0.6mm 相似文献
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双模式复数滤波器电路设计 总被引:2,自引:2,他引:0
采用0.18μm CMOS工艺,实现了一款中心频率和带宽可调节的OTA-C复数滤波器.通过设置控制字,可以控制复数滤波器的带宽和中心频率,形成窄带和宽带两种模式.滤波器的带宽设计为5 MHz和25 MHz,中心频率分别为4 MHz和15.4 MHz.窄带滤波器镜像抑制大于30dB(测试),宽带滤波器镜像抑制大于40 dB(仿真).设计中,采用了基于VCO锁相环结构的片上频率修正电路.滤波器消耗的总电流分别为1.7 mA和2.5 mA.仿真结果与测试结果非常吻合. 相似文献
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介绍了一种运用于电台宽带噪声测试系统中的带阻滤波器,主要阐述了切比雪夫滤波器的原理及该带阻滤波器的具体设计步骤.在实际制作滤波器时,利用先进设计系(Advanced Design System,ADS)软件进行仿真,调整各项设计参数,最后制作出达到指标要求的滤波器. 相似文献
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采用如今晶体滤波器设计中最为常用的格型电路,成功设计和研制出了用于通讯机中进行狭窄频带抑制的一种中高频带阻型晶体滤波器新产品.主要技术指标是:插损IL≤3dB、3dB带阻宽度BW3dB≤±3KHz、带阻衰减(限波)≥50dB、体积小、加工难度大等.研制的结果较好的满足了设计要求. 相似文献
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We describe a high-speed wavelength tunable liquid crystal filter which can be utilized as the tuning element at the receiving end of wavelength division multiaccess (WDMA) optical networks. The filter uses chiral smectic A electroclinic liquid crystals as the active cavity material in a Fabry-Perot etalon in order to obtain a microsecond switching speed. Using the commercially available BDH764E liquid crystal material, we demonstrate a tunable optical filter both in a bulk Fabry-Perot and a fiber Fabry-Perot (FFP) configuration. A bandwidth of about 0.7 mm and effective finesse of 70 were obtained in the FFP configuration. A FFP tuning range of 13 nm with a switching time of less than 10 μs were measured at the operating wavelength of 1.55 μm. A theoretical analysis of the expected filter performance in the FFP configuration is given. Diffraction in the Fabry-Perot cavity is identified as the dominant loss factor, resulting in reduced throughput and finesse broadening. It is calculated theoretically that an effective finesse of 130 and a throughput loss of 2.2 dB are achievable for a mirror finesse of 200 and a liquid crystal cavity thickness of 5 μm. A short waveguide piece is assumed to be included in the cavity. Other expected loss sources for the filter in the FFP configuration have been calculated, showing negligible effect on the filter performance 相似文献
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提出一种基于内全反射微环和光子晶体带隙相结合的混合结构空气孔型二维三角晶格光子晶体光分插滤波器,通过压缩及移位围绕线缺陷波导的上下两排光子晶体阵列,实现空气孔型线缺陷波导单模的有效调控,进而影响信道的下路效率,并且利用二维时域有限差分法系统分析不同波导宽度以及不同移位量δ时滤波器的下路效率。模拟计算表明,当波导宽度为0.8槡3晶格常数,耦合强度为0个晶格常数,移位量为0.5个晶格常数,信道波长为1464nm时,下路效率为-0.11dB,品质因子Q为1100;当波导宽度为0.8槡3晶格常数,耦合强度为1个晶格常数,移位量为0个晶格常数时,下路效率为-0.89dB,品质因子Q为2100。 相似文献
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The authors propose a simple structure for a tunable polarization-independent wavelength-selective filter. This successfully fabricated filter consists of a liquid crystal Fabry-Perot interferometer, a γ/4 plate, and a mirror. The input light is divided into a transmitted light and a reflected light. The polarization of this reflected light is rotated 90° by the γ/4 plate and the mirror and then this light is input again into the filter. The bandwidth is 0.48 nm and the tuning range is 50 nm. Fiber-to-fiber loss is approximately 3.9 dB and polarization dependence of the loss is approximately 0.3 dB 相似文献
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Tunable polarization diversity liquid-crystal wavelength filter 总被引:2,自引:0,他引:2
J.S. Patel M.W. Maeda 《Photonics Technology Letters, IEEE》1991,3(8):739-740
A compact polarization-insensitive liquid crystal filter is demonstrated using the polarization diversity technique. The incoming signal is split into two orthogonally polarized beams with a calcite crystal and the beams are filtered using two regions of the liquid crystal Fabry-Perot filter. The optic axes in these two regions are made orthogonal by controlling the surface structure. It is shown that a wide tuning range of 70 nm is possible with a band-pass of about 0.6 nm. Using arbitrarily polarized input light it is demonstrated that polarization-dependent power fluctuations are less than 1 dB.<> 相似文献
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M. Davanco Aimin Xing J.W. Raring E.L. Hu D.J. Blumenthal 《Photonics Technology Letters, IEEE》2006,18(10):1155-1157
A photonic crystal grating filter with an extremely wide rejection band and reduced modal back-reflections is proposed and demonstrated with a stopband extinction of 20 dB and insertion loss of less than 5 dB. The reflection-mitigation technique is shown to provide 10-15-dB reduction in reflected power. Guidelines for performance improvement are presented. 相似文献