New Materials for Superconductive Communication Cables

The feasibility of superconductive coaxial cables as a communication medium with an enormous capacity may be increased by applying superconductive materials with low surface resistances and high critical temperatures as well as dielectrics with low loss. This paper discusses the mechanisms affecting metallic conduction and dielectric properties of materials in relation to their application in a low temperature transmission line. It starts with a brief report on the present state of rf-superconductivity, but it particularly deals with the measurements of low temperature dielectric microwave losses of polymeric materials, because the dielectric loss mainly determines the overall-attenuation of the cable. Our investigations resulted in the smallest loss tangent of any solid material measured so far:tan delta (4.2 K, 6.5 GHz) = 6.6 dot 10^{-7}pm 5%for polyethylene. This corresponds to a cable attenuation of roughly 0.5 dB/km at 10 GHz and extends the bandwidth of superconductive communication lines appreciably.     

大功率微波柔软同轴电缆的研制

介绍了大功率微波柔软同轴电缆的设计思路,以及降低电缆衰减和提高电缆传输功率的有效途径。阐述了采用复合型聚四氟乙烯（F4）薄膜绕包绝缘的柔软同轴电缆的结构特性,其可在高传输功率环境下满足耐大功率、柔软性好、低损耗等的综合技术要求,并具有很好的应用前景。     

新型无线移动通信用物理发泡绝缘同轴射频电缆

介绍了CMRC公司设计制造的无线移动通信系统用物理发泡绝缘同轴射频电缆。这种电缆具有低损耗、低驻波、良好阻抗稳定性等优良性能。电缆优良的性能足以用于模拟或数字蜂窝状设备，以及广播、微波、陆地移动无线电、军用等领域。     

大长度低损耗半硬同轴电缆的研制

设计了一种采用膨体聚四氟乙烯作为绝缘,连续激光焊接铜管作为外导体的新型低损耗半硬同轴电缆,以打破传统的半硬同轴电缆制造长度的局限性,同时对电缆工艺的可行性进行了探讨。膨体聚四氟乙烯绝缘的采用降低了电缆的介电常数,减小了半硬同轴电缆高频段的传输损耗。连续焊接铜管外导体的采用不但增加电缆的制造长度,并且保留传统半硬同轴电缆良好的阻抗均匀性和屏蔽特性,同时也提高了生产效率,降低了材料消耗。     

物理发泡TPX绝缘射频同轴电缆的特性

聚4-甲基戊烯-1（TPX）材料具有极小的密度、优良的加工性能、较好的电气特性及较强的价格优势,耐温150℃（介于聚乙烯与聚四氟乙烯之间）,有望成为射频同轴电缆第三种亚高温绝缘介质材料。成功试制了泡沫TPX绝缘皱纹外导体1／4”射频同轴电缆,并对其进行了衰减、温度相位稳定性等主要电气性能的检测与对比。     

Submarine Coaxial Cable Pressure Characteristics

In equalization design of submarine coaxial cable system, the cable attenuation deviation due to pressure in deep sea bottom has significant weight. This paper treats the submarine coaxial cable characteristics pressure dependency. By using an artificial ocean test facility, 1.7 inch submarine coaxial cable attenuation, phase, capacitance and insulator core diameter were studied and their pressure coefficients under a pressure of 0 to 500kgw/cm^{2}at temperatures of 5, 10 and 20°C were obtained. In this study, pressure dependence of polyethylene dielectric constant and dissipation loss were quantitatively analyzed. The attenuation pressure coefficient varies with frequency. For example, cable attenuation in the sea at a depth of 5000 meters is higher than that on the land by 1.09 percent at 10 MHz and by 1.54 percent at 60 MHz at a temperature of 10°C.     

新型耐超高温、耐超高辐射射频同轴电缆的研制

简述了新型耐超高温、耐超高辐射射频同轴电缆的特点,包括耐超高温、耐超高辐射、抗腐蚀、抗震、抗磨及低损耗、高耐压、高绝缘电阻等性能。并着重介绍了发泡SiO2绝缘的新型耐超高温、耐超高辐射射频电缆内导体、绝缘、护套材料的选择以及导体整型、绝缘成型、护套成型的过程。     

Frequency characteristics of superconductive coaxial lines

By precise manufacturing methods, 1.6-mm 50-Ω superconductive coaxial lines having few impedance irregularities (0.2 to 0.3 Ω) have been produced. Their attenuation constant at 4.2 K shows a smooth gradual increase upto 12.4 GHz in proportion to frequency. The loss at 1 GHz is 0.7 dB/km for the line using tetra fluoroethylene-hexa fluoropropylene (FEP) and 1.6 dB/km for the line using polyethylene (PE).     

Improvement of Transmission Characteristics of Superconductive Coaxial Cable: Spectral Analysis of Dimensional Irregularity of Raw Materials of Coaxial Cable

This paper deals with the improvement of the transmission characteristics of superconductive coaxial line (SCCX), and presents a quantitative relationship between the Fourier component of the dimensional irregularities in the raw material of SCCX, such as the thickness of the copper tape and the diameter of the insulator, and an abnormal increase of the transmission loss due to the periodic impedance irregularities. This paper also shows that even for the coaxial cable with very small attenuation constant (≈ 0.5 dB/km) and high operating frequency (up to several gigahertz), an approximate formula for loss peak due to the periodic impedance irregularities holds for the production length of cable. This is indicated by the comparison of an approximate formula with the result of digital computer simulation.     

铜包铝线电缆在广电中的应用

通过对铜包铝线同轴电缆与铜导体同轴电缆的特性阻抗、低频电阻率、温度特性、衰减特性、回波损耗等性能参数的比较,论证了75Ω铜包铝线同轴电缆应用于有线电视网络、第一中频传输系统的工程可行性。     

铜包铝线在射频电缆中的应用

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U形漏泄同轴电缆的设计与实现

为达到某移动通信系统对漏泄同轴电缆主要电气指标的要求,设计一种U形漏泄同轴电缆,以满足工程应用。阐述了漏泄同轴电缆耦合损耗和传输衰减两个重要电气指标,以U形漏泄同轴电缆实例,利用三维电磁仿真软件HFSS仿真分析900 MHz工作频率下节距及槽孔尺寸的变化对耦合损耗、传输衰减的影响,仿真结果与实测结果吻合良好。结果表明U形漏泄同轴电缆节距越小,漏泄同轴电缆耦合损耗越小。     

馈线同轴电缆的全铝化

移动基站及布线用馈线同轴电缆受铜价飞涨的影响而使网络建设费用大幅攀升,以铝代铜的方法来降低产品成本是目前行业的一种基本思想和方法。馈线同轴电缆的全铝化就是受此思想的影响而派生的一种新产品。同规格的这种产品的传输性能与全铜产品相比,主要在传输衰减方面略显增加,这种增加也在用户或系统或以忍受的情况下方能成立。本文提出了电缆用的铝材要求、生产过程的注意事项、产品电气与机械传输参数的变化程度等问题,为全铝化同轴馈线电缆的行业标准制定及商用打下基础。     

皱纹外导体泡沫PE绝缘RF同轴电缆的衰减特性

衰减是射频(RF)同轴电缆最重要的传输特性.外导体皱纹深度及泡沫聚乙烯(PE)的介质损耗角正切tg δ是影响皱纹外导体泡沫PE绝缘同轴电缆衰减的主要因素.浅皱纹结构及净化介质材料是降低该电缆衰减值的有效途径.     

影响射频同轴电缆衰减的因素

本文对影响射频同轴电缆衰减的几个因素进行了分析,在分析中考虑到了电缆中空气层的存在,引入了等效绝缘层的概念。     

Miniature superconductive coaxial transmission lines

This is a review paper concisely tracing the development of miniature superconductive coaxial transmission lines from the original invention as a vertical channel signal delay line for fractional nanosecond pulse oscillography to present-day work towards highly compact, broad-band, and low-loss telecommunication cables. The present state of development yields a 1.6-mm coaxial line operating at 4.2K and having Pb conductors, polyethylene dielectric, Z0= 50 ± 0.3 Ω and a 1-GHz attenuation of the order of 1 dB/km. The attenuation up to 1 GHz is mainly due to dielectric losses.     

Numerical analysis of the propagation characteristics of multianglemultislot coaxial cable using moment method

In this paper, multiangle multislot coaxial cable is analyzed qualitatively and quantitatively. This is the extended result of the previous studies of the single-slot coaxial cable. The properties of this cable have been studied by many authors, especially for the surface-wave type. However, the slotted coaxial cable utilizing leaky waves has not been treated rigorously despite its wide use. In this paper, a numerical analysis of a leaky coaxial cable with a multiangle multislot configuration is performed to obtain many useful results, which are impossible to derive employing the approximate model frequently used in this area. Using the moment method, the propagation constant has been obtained for the leaky coaxial cable as a function of various parameters. Several slot configurations are considered to give insight into the properties of coupling loss and transmission loss complicated by simultaneous existence of leaky and surface waves     

光电复合海缆温度场建模分析及在在线监测中的应用

为了有效监测光电复合海缆的绝缘状况,基于迭代法改进了IEC60287电缆载流量和温度场计算标准,在有限元数值分析软件包COMSOL中基于热电耦合模块建立了110 kV YJQ41300 mm2海缆温度场模型,与改进IEC60287标准比较验证了建模方法的准确性,在此基础上确定了不同载流量下海缆模型最佳的分析范围。建模研究了海缆正常运行和绝缘性能下降情况下载流量和环境温度对光纤温升的影响;采用介质损耗表征绝缘状况,分析获得了典型介损值下光纤相对温升的变化规律。结果表明:正常情况下光纤温升随载流量的增加近似成平方增大,随环境温度的增加近似线性增大,增速较慢;海缆绝缘性能下降时光纤相对温升随tan的增加成正比增大,相对而言,受环境温度的影响很小。根据上述研究,提出了基于光纤相对温升和海缆载流量的介损计算公式和基于光纤相对温升的海缆绝缘状态监测方法。较之现有基于电气量的绝缘监测方法,该方法不易遭受电磁干扰的影响。在光电复合海缆在线监测方面具有参考应用价值。     

Resonance Properties of the Shield of a Coaxial Cable over a Ground Plane

In situations where several high-power transmitters and their antennas are to be used near one another, a certain amount of mutual interference can be expected. An instance of particular interest is that of high-intensity radiation inducing standing waves between the shields of nearby coaxial cables and a metal deck of ground plane. Standing waves induced may cause high potentials and possible breakdown at the ends of the cable, damaging connectors and antennas. There may also be some reduction of the shielding effectiveness of the coaxial cable when high-voltage standing waves are present in the shield. It has been common practice to eliminate such standing waves by periodic grounding of the outer conductor of the coaxial cable. This, however, requires penetration of the insulation material on the cable and formation of metal-to-metal joints on the shield. This is not only an inconvenient method of installation, but is also undesirable around salt water. Copper shielding will corrode, and corrosion at the joint of the dissimilar metal can cause nonlinear interference effects. The standing waves induced in the transmission system formed by the cylindrical shield of a coaxial cable and a conducting plane are examined theoretically and experimentally as a function of the shield-to-ground impedance at the end points only (Z1 and Z2 of Fig. 1). Ordinarily, standing waves are eliminated by terminating a guiding system in its characteristic impedance. In this situation, however, the exciting source (i.e., incident radiation) is distributed along the length of the transmission system.     

8D—FB型同轴电缆生产工艺的探讨

介绍了8D-FB型同轴电缆的结构及生产工艺。详细分析了温度循环试验后引起8D-FB型同轴电缆内导体突出的主要原因,针对导致电缆内导体突出的主要原因,对生产工艺进行了改进,从根本上解决了该问题,并且经过反复试验验证工艺改进后生产的8D-FB型同轴电缆的衰减性能基本没有改变。