EMI电源滤波器的设计探讨

电源EMI滤波器是一种抑制传导发射和辐射发射非常有效的方法.分析了电源线上的干扰类型,开关电源产生EMI的原理及其拓扑结构.讨论了电源EMI滤波器的设计和器件选取原则,并提出有关安装电源EMI滤波器时应注意的几个问题.     

电源滤波器使用中的常见错误

在实验测试过程中,我们常遇到这样的情况:虽然设计工程师在设备电源线上接了电源滤波器,但是该设备还是不能通过"传导骚扰电压发射"测试,工程师怀疑滤波器的滤波效果不好,不断更换滤波器,仍不能得到理想的效果.     

2020 IEEE EMC&SIPI虚拟会议——提名文章(四)

Testing of a Module for Electrical SubstationS to Demonstrate HEMP and IEMI Protection and GIC Detection 摘要:为了保证安装在变电站中的模块设计的可行性,该模块可以防止电磁武器的早期高空核爆电磁脉冲(E1 HEMP)和有意电磁干扰(IEMI)等大功率电磁干扰,本文进行了一系列测试并给出了相应测试结果. 关键词:HEMP;IEMI;地磁感应电流;辐射和传导测试 根据MIL-STD-188-125-1和IEC 61000-5-10的原则,需要进行相关试验,以确保设计充分.本文涉及的内容包括: ●评估模块及其门的屏蔽效能; ●确定外部场地电缆上的感应电流; ●评估和选择场地电缆上的电缆屏蔽层; ●测试保护模块的电源滤波器; ●测试截止线以下的光纤电缆和气流波导; ●评估电子设备运行产生的内部磁场; ●完全威胁等级E1HEMP测试的结果.     

基于UPS中电磁干扰噪声的一阶滤波器的设计

从分析传导测试原理入手,建立了针对差模干扰信号的一阶滤波器的电路等效模型;并进行理论分析计算和数学公式推导,得到一阶滤波器的理论设计方法和规范步骤.     

开关电源EMI滤波器的设计与仿真

滤波是抑制传导干扰的一种常用方法,为了提高滤波器性能和缩短开发时间,针对DC-DC开关电源介绍一种简单且效果良好的滤波器设计方法.阐述EMI电源滤波器的基本原理、拓扑结构、设计原则和滤波器件的高频特性,建立滤波器插入损耗仿真模型,对设计结果进行分析,最后通过实际测试,验证设计方法的正确性.同时,在EMI电源滤波器设计的基础上,对滤波器进行拓展功能的电路设计,主要针对开关动作所引起的浪涌电压.     

通过扫描电源的频率来降低电磁干扰

开关电源可能是众所周知的噪声发生器.您应该防止这些被传导或辐射的噪声返回输入源,因为这一噪声会给使用同一输入电源的其他器件造成严重损坏.电磁干扰滤波器的目标是阻止这些噪声,并提供一条返回噪声源的低阻抗路径.这种噪声越大,滤波器设计的规模、费用和难度就越大.固定频率开关电源在这一固定基频上产生最大的电磁干扰辐射,此外,还有在开关频率的倍数上产生电磁干扰辐射,但其幅度(强度)有所减小.图1所示简单电路使开关转换器能在多个频率而不是单个频率上工作,从而降低了任何一个频率上工作的平均时间.该方案能有效地降低峰值辐射量.     

一种基于电磁超材料的抗干扰天线

设计了一种基于电磁超材料的抗干扰天线.该抗干扰天线由矩形波导腔体,铺设于波导腔体底部宽边的电磁超材料以及位于波导腔体上部宽边的辐射缝隙构成.当电磁超材料表现为完美电导体时,该抗干扰天线同传统波导缝隙天线类似,可高效辐射电磁波.当电磁超材料表现为完美磁导体时,该抗干扰天线的性能与带阻滤波器相似,可抑制特定频段的干扰电磁波.该抗干扰天线实现了天线与滤波器的高度集成,结构紧凑.仿真与测试结果显示该抗干扰天线在工作频段具有良好的辐射特性,同时对干扰频段电磁波的抑制可达40 dB.     

EMI电源滤波器的设计与应用技术

在EMC领域中，EMI电源滤波器的设计和应用非常重要，它是抑制传导发射和辐射发射的有效方法之一。本文主要从以下几个方面讨论了EMI电源滤波器的设计与应用技术：1）EMI电源滤波器的基本原理、种类及主要特性指标；2）电源线上的干扰类型及EMI电源滤波器的作用：3）EMI电源滤波器的设计及工艺要求；4）EMI电源滤波器的安装要求。     

基于滤波器电路设计多层带通频率选择表面

针对传统多层频率选择表面（frequency selective surface，FSS）的设计存在计算量大、耗时长等问题，提出了一种基于滤波器理论和FSS等效电路设计多层FSS的方法.该方法先由滤波器理论综合得到多层FSS的等效电路，再利用FSS等效电路的反演方法将其电路模型转换成多层FSS的结构参数.物理过程简单直观，可以实现任意层数的高阶FSS的快速精确设计.为了验证该方法的准确性，完成了一种K波段带通型三阶FSS天线罩设计以及实物样件加工、测试.测试结果表明该天线罩的传输曲线与滤波器理论设计结果基本一致，且对天线辐射方向图的影响较小，为多层FSS的精确设计提供了一种精确理论设计方法.     

一种在线测量杜瓦冷损的数值方法

提出了一种在线测量杜瓦辐射漏热、传导漏热及总漏热的数值方法.该方法利用了杜瓦冷头温度变化与辐射漏热、传导漏热之间的函数关系,通过对冷头的温度变化曲线进行数值拟合,逆向导出冷损的表达式.在不破坏原有杜瓦与制冷机耦合状态的情况下同时测出杜瓦的辐射漏热及热传导漏热,不但解决了热学异常的原因定位问题,也给出了在各个温度下的两种漏热具体值.试验结果表明,该方法简单高效,测试结果可靠,为杜瓦的热学设计及热学失效分析提供了有效的试验验证手段.     

Use of the Dielectric Resonator Antenna as a Filter Element

For the first time, the dielectric resonator antenna (DRA) is simultaneously used as a filtering device, named as the DRA filter (DRAF). The theory and design methodology of the DRAF are elucidated using the cylindrical DR. It was found that the operating frequency of the filter part can be made equal to, or different from, that of the antenna part. The return loss, input impedance, radiation patterns, and insertion loss of the DRAF are studied. To improve the insertion loss of the filter part, the DR is top-loaded by a metallic disk without significantly affecting the radiation efficiency of the antenna part. The disk, in addition, can be used to tune the frequency of the filter. It was found that the antenna and filter parts of the DRAF can be designed and tuned almost independently. A second-order DRAF is also designed in this paper. As the dual function DRAF is compact and cost effective, it should find applications in modern wireless communication systems.     

一种基于DGS结构的新型双模双通带滤波器

提出了一种新颖的基于缺陷地结构(DGS)的双模双通带滤波器.该滤波器由印制板顶面的一个方形谐振单元和另一个巧妙嵌入在印制板底面DGS中的方形谐振单元并联构成,具有结构紧凑、易于加工的特点.每个谐振单元都具有双模单通带传输特性,可通过公共馈线同时激励实现双模双通带滤波.两个谐振单元的谐振频率相对可调,提高了设计上的灵活性.为减少辐射损耗并改善高频通带插损,使用准共面波导缺陷地结构对底面谐振单元进行了改进.最后,实验制作了两种双模双通带滤波器,测试结果与仿真结果吻合较好.     

基于ADS的平行耦合线带通滤波器的优化设计

从归一化低通滤波器出发,阐述了平行耦合线带通滤波器的工作原理和设计过程。给出了一个中心频率在C波段的带通滤波器设计实例。根据给定的滤波器技术指标,确定滤波器类型、结构和最佳级数。按照设计要求利用射频和微波设计软件ADS(先进设计系统)对带外抑制和插入损耗进行优化设计,从而达到要求的插损、带内波纹和理想的带外抑制特性。给出了优化的结果仿真图,结果表明优化结果与设计要求一致。     

Triple Mode Use of a Single Dielectric Resonator

A single dielectric resonator is used for a triple mode operation in filtering and dual band radiation purposes. A high unloaded quality factor over 2300 at 2.43 GHz is obtained simultaneously with both broadside and omni-directional radiation patterns of 7% and 8% bandwidths around 2.47 and 3.36 GHz, respectively. Series of parametric studies are developed to tune the filter's operating frequency range, to enhance its insertion loss and to obtain a sharp filtering skirt behavior. Finally, measurements of both filter insertion loss and antenna return loss, coupling coefficients and radiation patterns are illustrated for further verification.      

SIR结构ACPW滤波器研究

文章提出将SIR谐振器结构应用于非对称共面波导传输线中,设计了一种新型SIR结构非对称共面波导带阻滤波器。通过四个SIR谐振单元在非对称共面波导传输线中级联,有效地改善了滤波器的插损和带宽。结果显示,本滤波器中心频率为1．8GHz,最小插损为0．4dB,相对带宽为33．3％,最大带外抑制为-60dB。具有小体积、低插损、高抑制、宽阻带、易于加工等优点。     

基于平衡技术的微带低通滤波器版图优化设计

微带线结构的不连续性,使反射损耗和插入损耗较大,影响滤波器性能。利用平衡法提升滤波器并联分支中较低的特性阻抗,达到降低微带线宽度的目的,从而均衡整个滤波器的宽度,使版图仿真优化。以一个5阶切比雪夫微带低通滤波器设计为例,仿真结果表明,滤波器通带内反射损耗从-9.566dB降低到-15.837dB,插入损耗从0.679dB降低到0.322dB,与直接采用Richards变换和Kuroda规则设计微带低通滤波器相比,该方法能缩短滤波器设计周期,获得满意的滤波器性能。     

Electronically switchable and tunable coplanar waveguide-slotlineband-pass filters

A coplanar waveguide (CPW)-slotline bandpass filter is described. The circuit allows planar integration of active and passive semiconductor devices both in series and in shunt. A microstrip-to-slotline transition designed to test the filter is also described. Two of the transitions exhibit an insertion loss of less than 1.0 dB over the 2.0-4.0-GHz range. A three-section CPW-slotline bandpass filter demonstrates an insertion loss of less than 0.2 dB over the passband centered at 2.9 GHz. A three-section CPW-slotline switchable bandpass filter integrated with three p-i-n diodes is discussed. It has a 0.7-dB insertion loss in the passband when the p-i-n diodes are off and a 25.0-dB isolation across the entire band when the p-i-n diodes are on. A three-section CPW-slotline varactor-tunable filter integrated with three varactor diodes is presented, showing a 2.0-dB insertion loss and over 20% electronic tuning range. Simple transmission line circuit models are used to optimize the design     

A 60-GHz Millimeter-Wave Bandpass Filter Using 0.18-μm CMOS Technology

This letter presents the design and implementation of a 60-GHz millimeter-wave RF-integrated-circuit-on-chip bandpass filter using a 0.18-mum standard CMOS process. A planar ring resonator structure with dual-transmission zeros was adopted in the design of this CMOS filter. The die size of the chip is 1.148times1.49 mm². The investigations of sensitivity to the insertion loss and the passband bandwidth for different perturbation stub sizes are also studied. The filter has a 3-dB bandwidth of about 12 GHz at the center frequency of 64 GHz. The measured insertion loss of the passband is about 4.9 dB, and the return loss is better than 10 dB within the passband.     

A modified Chebyshev bandpass filter with attenuation poles in thestopband

This paper describes a design method of a modified Chebyshev bandpass filter with attenuation poles in the stopband. The insertion of attenuation poles into resonators in the authors' bandpass-filter design is accomplished by connecting a lumped inductor or capacitor in series with a shunt-type coaxial transmission-line resonator. The inserted poles which are distributed over the stopband can be chosen such that the insertion loss of the filter has equiripple characteristic and maximum attenuation in the stopband with the given number of attenuation poles. The modified Chebyshev bandpass filter designed by this method can be effectively used in diplexer design     

A Dissipative Coaxial RFI Filter

A lossy coaxial filter has been developed to protect electroexplosive devices from accidental detonation by stray high-power RF fields. The characteristics of a coaxial transmission line, filled with dielectromagnetic material, are analyzed in terms of various proposed filter configurations. The design concept for the prototype filter is chosen so as to provide a maximum stop-band attenuation. Measured results are presented to show that the filter provides an insertion loss of about 90 db from 5 Mc to at least 10 kMc. Furthermore, it is shown that the use of a lossy filter guarantees a minimum value of insertion loss regardless of the terminating impedances.