Simple technique for the measurement of the transfer impedance ofvariable length coaxial interconnecting leads

An experimental technique for the routine measurement of the transfer impedance of variable length coaxial leads was developed. Ready-made leads incorporating connectors at either end can be evaluated either for the purposes of quality control during manufacture or when performing general electromagnetic compatibility (EMC) troubleshooting. A low-cost measurement fixture is proposed and the measurement method is elementary. Lead lengths of up to a few meters in length can be measured up to frequencies of approximately 300 MHz. Measured results for RG-58 cables are presented and compared to published values to validate the method     

A 0.18-/spl mu/m CMOS 3.5-gb/s continuous-time adaptive cable equalizer using enhanced low-frequency gain control method

This paper describes a high-speed CMOS adaptive cable equalizer using an enhanced low-frequency gain control method. The additional low-frequency gain control loop enables the use of an open-loop equalizing filter, which alleviates the speed bottleneck of the conventional adaptation method. In addition, combined adaptation of low-frequency gain and high-frequency boosting improves the adaptation accuracy while supporting high-frequency operation. The open-loop equalizing filter incorporates a merged-path topology and offers infinite input impedance, which are suitable for higher frequency operation and cascaded design. This equalizing filter controls its common-mode output voltage level in a feedforward manner, thereby improving bandwidth. A prototype chip was fabricated in 0.18-/spl mu/m four-metal mixed-mode CMOS technology. The realized active area is 0.48/spl times/0.73 mm/sup 2/. The prototype adaptive equalizer operates up to 3.5 Gb/s over a 15-m RG-58 coaxial cable with 1.8-V supply and dissipates 80 mW. Moreover, the equalizing filter in manual adjustment mode operates up to 5 Gb/s over a 15-m RG-58 coaxial cable.     

An L-Band Loop-Type Coupler (Correspondence)

The design of loop couplers for various loop length has been reported by Lombardini, Schwartz and Kelly. This device is useful for many applications as the over-all length can be held to about 6 inches, whereas a com-parable multihole coupler must be on the order of several feet long. The loop-type device couples a TE/sub 10/ waveguide mode from a RG-69/U to a TEM mode in a 3/8-inch coaxial line. A comb-type coupler, for coupling a coaxial line to TE/sub I0/ waveguide, was reported by Lombardini and Schwartz. This device made use of a multiple-capacitive probe situated in a longitudinal slot in the top wall of the waveguide.     

Time-Domain Measurement of Loss and Dispersion (Short Papers)

Time-domain metrology (TDM) techniques are applied to determine loss and dispersion in microstrip and coaxial cable for possible future use in interconnections in the frequency range of 0.4-10 GHz. After a brief presentation of the method, results are given for microstrip, RG/U 58, and RG/U 188A coaxial cable. Good agreement is obtained between measured, computed, and published values. Major advantages of the technique are that unwanted multiple reflections can be excluded from the measurement time window, and errors from interface discontinuities can be evaluated and removed from the final result.     

A low power 3.125 Gbps CMOS analog equalizer for serial links

A CMOS analog equalizer is designed to meet the different high speed communication specifications,such as USB 2.0,PCI-E and rapid IO.The proposed circuit architecture could facilitate the wide frequency scale ranging from 1 to 3.125 Gbps by adjusting the locations of pole and zero,so that the circuit can change its response accordingly as the channel characteristic alters.In order to balance the parasitic capacitors in the internal point,symmetric switches are addressed to generate the equal load for dif...     

Time-domain skin-effect model for transient analysis of lossy transmission lines

A skin-effect equivalent circuit consisting of resistors and inductors is derived from the skin-effect differential equations for simulating the loss of a transmission line. A numerical method is used to analyze the transmission-line differential equations and the skin-effect equivalent circuit, yielding a model which relates the new values of node voltages and line currents to their values at the previous time step. Based on this model, a very simple program was written on a desk-top computer for the transient analysis of lossy trammission lines. Two examples are presented. The first example is an analysis of the step and pulse responses of a 600-m RG-8/U coaxial cable. The computed results show excellent agreement with measured data. The second example studies the current at the end of a 12-in 7-Ω strip line under different loading conditions. Very good agreement has been obtained between the calculated steady-state solution and that obtained by the frequency-domain method.     

整体镀锡外导体半柔同轴电缆

详细介绍了整体镀锡外导体半柔同轴电缆的设计、生产工艺，并与美国Belden公司半柔同轴电缆和国内无缝铜管外导体半硬同轴电缆进行了对比。目前该产品已广泛应用于通信、导航等无线电电子设备中。     

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。     

Broad-Band Stepped Transformers from Rectangular to Double-Ridged Waveguide

The design of a series of broad-band Tchebycheff-type stepped waveguide transformers from various sizes of standard rectangular waveguides to a double ridged waveguide covering the frequency range of 4750 to 11,000 mc is described. Four separate transformers employing RG-67/U (WR-90), RG-68/U (WR-112), RG-106/U (WR-137), and WR-159 to Airtron ARA-133 double-ridged waveguide have been designed using this technique and cast in aluminum. The complete frequency range is covered by several pairs depending on which sizes of mating rectangular waveguides are desired. The RG-106/U design covers a frequency range of 53 per cent with a maximum VSWR of 1.08, while the other three designs each cover a slightly smaller frequency band with a VSWR not exceeding 1.05. Along with the experimental results obtained, an outline of the design method is given which can be used to design similar transformers between any compatible rectangular and double ridged waveguides.     

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.     

Through-pulse measurements on installed 1.2/4.4 mm coaxial cables: two examples

Through-pulse measurements have been performed on several installed 1.2/4.4 mm coaxial cables to record their forward, echo characteristics for possible operation up to 565 Mbit/s- Two typical examples are presented that illustrate the effects of both the random and periodic irregularities within such cables.     

Theory of coupled monopoles

Accurate numerical values of mutual and self-admittances are obtained for an array consisting of two monopoles having different lengths and radii. The monopoles are actually protrusions of the inner conductors of coaxial cables. The sheaths of the cables are connected to a perfectly conducting ground screen. Restrictions in the theory are the following: the monopoles must be thin,a/lambda ll 1whereais the radius andlambdathe wavelength,b < 3awherebis the radius of the coaxial cable sheath, andd > 10awheredis the separation of the monopoles. The procedure employed to obtain the mutual and self-admittances is to derive simultaneous integral equations for the current distributions and to solve the integral equations numerically. The results are given for the most part in graphical form. Comparisons are made with existing theory and with experimental data. Excellent agreement in all cases is observed.     

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。     

Theory and analysis of leaky coaxial cables with periodic slots

Frequency band and coupling loss are the two important parameters of leaky coaxial cables with periodic slots. The frequency band can be predicted by analyzing the arrangement of the slots on the outer shield of the cable, but the coupling loss is not so easy to determine by classical methods. In this paper, the finite-difference time-domain (FDTD) method is used to calculate the electric field distribution in the slot cut in the outer conductor of the coaxial cable. The dyadic Green's function is then used to calculate the radiation field of the equivalent surface magnetic current densities. By these two methods, the coupling losses of the leaky coaxial cables with different periods, sizes and shapes of the slots can be accurately obtained. Some results in this paper were verified by the experimental results of leaky coaxial cables designed for railway mobile communications with a frequency band of 100-500 MHz     

铜包铝线在射频电缆中的应用

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束绞型外导体低损耗微波同轴电缆

束绞型外导体同轴电缆以其加工方便,生产周期短,电性能参数一致性好等优势在近几年的市场上脱颖而出.介绍了目前束绞型外导体同轴电缆中较为典型的SFCG-50-5-51型低损耗柔软同轴电缆的结构和低损耗的性能.     

Simple impedance transforming feed system for low-gain quadrifilarand bifilar satellite terminal antennas

An impedance transforming balun feeder system has been devised for low-gain antennas such as quadrifilar helices and spirals, consisting of four coaxial cables and a microstrip circuit. The arrangement allows physically orthogonal `balanced pair' outputs with quadrature phasing, in space limited configurations     

漏泄同轴电缆在建筑物内无线通信中的应用

分析漏泄同轴电缆的辐射机理，比较了漏泄同轴电缆和天线在建筑物内无线通信中的应用，提出了一套用于解决建筑物内无线通信的漏泄同轴电缆方案，并给出了设计实例。该方案可以保证建筑物内电磁波均匀全面的覆盖，从而改善通信的质量。     

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。     

Coaxial Cables as Sources of Intermodulation Interference at Microwave Frequencies

Intermodulation interference arising from nonlinearities in braided coaxial cables at microwave frequencies is discussed. Detailed investigations have been carried out using a large number of commercially available and specially constructed cables to isolate and assess the relative contributions of different parameters of coaxial cables responsible for the generation of intermodulation products (IP's) at L-, S-, and C-band frequencies centered on 1.5, 3, and 5 GHz. Ambient temperature in the case of polythene dielectric cables and oxides on copper-wire braids affect considerably the IP's generated in a coaxial cable.