电波暗室特性简介

电波暗室（Anechoic Chamber）又称电波消声室，或电波无反射室。有两种结构形式：电磁屏蔽半电波暗室（Electromagnetic Shielded Semi—Anechoic Chamber）和微波电波暗室（Microwave Anechoic Chamber）。     

5米法电波暗室

在电磁兼容工程中，有经验的工程师都知道，许多电子产品的电磁兼容测试可在屏蔽的半电波暗室中进行，这种暗室通常有两种尺寸：天线与待测产品相距3m的3米法暗室及天线与待测产品相距10m的10米法电波暗室。半电波暗……     

用于电磁兼容测量的电磁屏蔽半电波暗室

详细介绍了电磁屏蔽半电波暗室主要技术指标和设计要求,讨论了暗室设计中需考虑的一些实际问题和注意事项,为EMC暗室建设和验收提供依据.     

电磁兼容测试场地性能及影响要素

0前言 电波暗室是电磁兼容测试的环境和场地.电磁兼容测试场地大致分为开阔场(open site),半电波暗室(semi-anechoic chamber)和全电波暗室(fully-anechoic chamber).早期的电磁兼容测试是在开阔场中进行的.随着社会的发展,电磁环境日益复杂,人类活动范围扩展,很难找到符合要求的开阔场,于是开阔场的替代场--半电波暗室就应运而生了.但是由于存在地面反射,半电波暗室中的理论计算十分复杂,而且往往测试数据和理论计算也有较大的差距.于是人们又寻求更接近自由空间测试条件,随着吸波材料技术的发展,全电波暗室出现了,暗室6面都装有吸波材料,模拟自由空间,克服了半电波暗室的一些缺点.     

大功率电机RE测试用高速穿墙屏蔽轴的研制

针对电动汽车高转速、大扭矩电机的电磁辐射特性测试时电波暗室内、外的电磁隔离问题,在研究电机检测系统电磁辐射特性的基础上,提出了高速穿墙屏蔽轴系统三种设计方案。经仿真对比及应用验证,穿墙波导管外套一个内壁贴吸波尖劈的屏蔽暗箱,可大幅度提高暗室屏蔽效能,解决汽车驱动电机带载状态下辐射发射认证测试时电波暗室的电磁隔离问题。     

各种电波暗室在无线电管理检测中应用的探讨

介绍了各种电波暗室的类型、每种暗室的性能指标、在各种暗室通常能够进行的测试,以及在无线电管理所需检测工作中能够完成的检测项目;阐述了利用测试设备进行暗室性能测定的经验以及如何按照国家实验室认可准则的要求,科学地使用、维护电波暗室。     

电波暗室的建造和管理

介绍电波暗室的类型、各种吸波材料的特点,并通过许多实例,阐述电波暗室的材料选型以及电波暗室建造和管理方面的经验.     

电波暗室的分类及半电波暗室的性能评价指标

介绍了电波暗室的种类,并对电波暗室性能的各项评价指标作了阐述,对相应的有关标准进行了说明.     

全电波暗室30MHz～1GHz场地确认方法

该文介绍了全电波暗室30MHz～1GHz场地确认的方法,并对本单位5m全电波暗室的实际测试结果进行了分析总结。     

10米法半电波暗室性能要求与建设

文章主要介绍了电波暗室的种类以及电波暗室性能的各项评价指标、性能要求、测试点和依据标准。结合山东省质检院10米法半电波暗室的建设经验,重点阐述了半电波暗室在设计和施工中需注意的问题。     

混响室法欠模状态屏蔽体屏蔽效能测试技术研究

欠模状态下屏蔽壳体内部场分布不均匀,屏蔽效能测量结果与位置相关,因此需要利用探头或单极子天线进行多位置测量,过程繁琐。文中利用长线天线来测量欠模状态下屏蔽壳体屏蔽效能,并与单极子天线测量结果进行比较。在暗室中测量天线自由空间反射系数S₁₁;在混响室中利用不同天线测量屏蔽壳体的屏蔽效能,并利用S₂₂分析腔体谐振特性。测量结果表明,长线天线宽频带匹配特性优于单极子天线,测量的屏蔽效能能够更好地反映屏蔽体谐振特性,为屏蔽壳体的屏蔽效能测试评估提供了指南,具有工程应用价值。     

半电波暗室建设的工艺问题

屏蔽室的建造水平及吸波材料的安装方式直接影响着电波暗室的性能.介绍半电波暗室建造中,组合式屏蔽室及吸波材料的工艺技术要求.     

屏蔽室和半电波暗室设计施工的若干问题

介绍了屏蔽室和半电波暗室在设计和施工中需要注意的一些问题,例如:总体布局、供电照明、接地、通风、接口板、吸波材料选用、使用维护等.     

暗室工程的概念设计

从暗室使用者的角度,结合暗室的测试功能、无反射特性、屏蔽效能、测量设备和测量方法等方面,以举例的方式,介绍一些暗室概念设计的思路和方法,以期暗室建成后的性能能达到初始期望的要求。     

Effect of the second filler which melted during composite fabrication on the electrical properties of short fiber polymer-matrix composites

This paper presents a method for greatly enhancing the electrical conductivity and electromagnetic interference shielding effectiveness of short conducting fiber filled polymers. This method involves the addition of a small proportion of metal particles as a second filler to the fiber polymer-matrix composite. The key to the method is that the metal particles melt during the composite fabrication, so that the metal electrically connects the metal-coated carbon fibers to a certain degree, thereby resulting in a partially connected three-dimensional network. By adding 2 vol% tin-lead particles to 20 vol% short nickel-coated carbon fiber filled polyether sulfone, the electrical resistivity was decreased by a factor of 2000, while the shielding effectiveness at 1 GHz was increased from 19 to 45 dB. No such improvement was found for the same volume fraction of tinlead particles added to an uncoated carbon fiber composite. This difference is due to the superior wetting of solder with nickel compared to that of solder with carbon, as shown by contact angle measurements. This paper is an extended version of a paper presented at the 6th Int. SAMPE Electron. Mater, and Processes Conf., June 1992.     

Electromagnetic shielding of nylon-66 composites applied to laser modules

Electromagnetic shielding of nylon-66 composites applied to laser modules was studied experimentally and theoretically. The effects of conductive carbon fiber length and weight percentage upon the shielding effectiveness (SE) of nylon composites were investigated. The SE of long carbon fiber filled nylon-66 composites was found to be higher than short carbon fiber composites under the same weight percentage of carbon fibers. In addition, higher electromagnetic shielding was obtained for the composite with higher carbon fibers contents at the same length. The SE of conductive carbon fiber filled nylon-66 composites was measured to be 42 dB at a low frequency of 30 MHz and 50 dB at a high frequency of 1 GHz. The SE predicted by theoretical models and measured by experiments were in good agreement for filled nylon-66 composites with different length fiber.     

Shielding Measurements of Equipment Enclosures in the Radiating Near Field

To evaluate the shielding performance of an equipment-level enclosure, a new measure termed shielding power ratio is proposed, which includes the average shielding power ratio (AS) and a statistically based enhancement factor. Two measurement environments, the anechoic chamber and the reverberation chamber, are considered and compared. To achieve a quick estimate of such measure, the reverberation chamber is proposed to measure the AS. The enhancement factor can be derived from the statistical analysis on both measurement results and simulation results. Based on the enhancement factor and the total radiated power, the maximum power density radiated from the enclosure can be estimated accurately. The paper is informing new developments in IEEE Standard 299.     

近场EMC测试技术

随着电探头、磁探头和电磁算法的不断完善,近场扫描技术有望与电磁兼容暗室、微波混响室等一起构成近场、远场一体化的电磁兼容测试系统。总结了近场测试技术的一些进展,主要包括利用感应区的电磁场重构等效辐射源,测量弱辐射体的屏蔽效能,以及多分量电磁探头的设计。     

弹道中段进动目标非理想散射中心微动特性研究

 传统中段进动目标微动特性研究通常将目标散射中心视为理想散射中心,且用目标自身进动来等效散射中心的运动,据此所得结论具有一定局限性.本文揭示了中段目标自身进动与散射中心运动的异同,综合考虑了实际散射中心的非理想散射现象和遮挡效应,建立了基于非理想散射中心的中段进动目标回波模型,并利用仿真实验分析了不同进动参数对时频特性的影响,通过暗室进动实验证明了本文结果的正确性.