A genetic approach to the synthesis of composite right/left-handed transmission line impedance matching sections

A genetic approach for the synthesis of composite right/left-handed (CRLH) transmission line impedance matching sections is presented. Continuous parameter genetic algorithm (CPGA) is used for the synthesis. Examples for a uniform CRLH transmission line impedance matching section and a nonuniform CRLH transmission line impedance matching section are given.     

Impedance matching with a series transmission line section

A generalization of the transmission line quarter-wave impedance matching transformer is presented. The resultant series-section transformer can match complex as well as pure resistance loads to a transmission line, and the choice of the characteristic impedance of the matching section is not restricted to a single value.     

An exponentially tapered transmission line antenna

The analysis and design of an exponentially tapered transmission line antenna is presented. The exponentially tapered transmission line is designed to operate such that it has radiator characteristics at high frequency and serves as a matching section at low frequency. The NEC-2 is used to model the antenna at frequencies ranging from 500 MHz to 1 GHz to obtain the input impedance and the desired radiation pattern     

Analysis of a MEMS transmission line

A microelectromechanical system (MEMS) sound waveguide is considered as a transmission line for RF signals. We analyze a device geometry of a straight one-dimensional microsize silicon rod, where a longitudinal acoustic wave is generated and detected using capacitive transducers. Linear, isotropic, and nondispersive acoustic-wave propagation is assumed. Based on the calculation of the electromechanical impedance, an electrical equivalent model is derived for the acoustic transmission line. A numerical example and a comparison to measured properties of a MEMS-transmission-line resonator shows that the characteristic impedance level of the waveguide is typically high, which causes challenges for matched termination. Solutions to overcome the matching problems are discussed.     

Step response of lossless parabolic transmission line

The response of a parabolically tapered transmission line to an ideal voltage step is derived. The resulting expressions are simple exponential functions and thus enable a fast characterisation of the transient behaviour of such lines when used as pulse transformers or matching sections.     

Calculation of capacitance for rectangular coaxial strip transmission line

The field matching method is used to calculate the capacitance of coaxial rectangular strip transmission line. This method is simple, can be used conveniently and the magnitude of error can be effectively controlled.     

传输线的反射干扰

在数字信号处理系统中,时钟信号和数字信号传输因传输始端和终端阻抗不匹配而引起反射干扰,使传输信号的波形出现上冲、下降和振荡。为了抑制这种因阻抗不匹配引起的反射,本文首先从产生这种反射的原因和造成的重大危害分析,提出了反射干扰这一亟待解决的问题;接着从传输线的阻抗特性以及阻抗匹配原理出发,提出了始端和终端阻抗匹配原则,最后给出了几种减小和抑制反射干扰的方法,实践证明使用阻抗匹配这一方法在减小反射干扰是十分有效的。     

Transmission line aspects of the design of broad-band electrooptic traveling-wave modulators

This paper proposes a two-layer traveling-wave type electrooptic modulator structure to maximize modulation bandwidth from transmission line aspects. This structure can be designed to satisfy the velocity matching and impedance matching condition simultaneously. A design method for this structure is discussed.     

Proposal for a 94-GHz phase-reversal optical modulator using a loaded transmission line

One of the most important problems associated with the design of external travelling wave optical modulators operating at very high frequency is the reduction of microwave loss associated with the electrode structure. With this in view, a new design for a Ti:LiNbO/sub 3/ narrow-band optical modulator is proposed for operation at 94 GHz. It uses a low-loss loaded transmission line with dielectric overlay and uses phase-reversals to achieve phase matching. Numerical simulations predict a required 21-dBm drive power for full on-off switching at 94 GHz.     

同轴-径向波导接头分析与设计

由并矢格林函数－模式匹配法导出场表达式后,利用矩量法精确计算了同轴－径向波导接头的ｓ参数。从而确定了接头具有最佳传输特性的结构尺寸。通过对比结果,讨论了用传输线理论设计该接头的条件。     

频带展宽的复合左右手传输线偶极子天线

针对周期复合左/右手(Composite Right/Left-Handed, CRLH)传输线偶极子天线带宽窄的问题, 提出一种非周期CRLH传输线的天线模型.该模型主要由N个不同尺寸的LC梯形网络单元组成, 实现参差调谐, 改善天线的阻抗匹配, 拓展天线带宽.设计了一种四单元非周期CRLH偶极子天线, 模拟和实验测试结果表明:天线的长度为0.135λ₀时, 满足回波损耗|S₁₁|≤-10 dB的相对阻抗带宽为8.55%, 天线的匹配性能得到了改善.     

Diagnosing transmission line termination faults by means of waveletbased crosstalk signature recognition

This paper describes a technique that allows one to identify the faulty condition (open or short circuit) at a termination of a multiconductor transmission line structure by measuring the induced voltage at the other end. The wavelet theory is used to filter out from the signal the components due to unwanted sources, and to decompose it to obtain the fault's signature. The comparison (or matching) algorithm is substituted by an artificial neural network. Two differently designed neural networks are used to validate the results and the overall procedure is also tested on an experimental set-up     

An extremely small transmission line antenna for DAB VHF band

This paper is to present a design method for an extremely small antenna, which is based on the traditional concept of transmission line antenna. Physically, it is composed of a short section of planar transmission line antenna and a long and slender cable. Since this slender cable can be wound and attached on the planar section, the whole apparent size is small even it is operating for DAB (Digital Audio Broadcasting) VHF band. Special techniques are applied for the purpose of impedance matching.     

Digital subscriber line technology facilitates a gracefultransition from copper to fiber

The loop environment and the techniques that historically have been used for providing transmission treatment are reviewed. The digital subscriber line (DSL), which applies adaptive filtering to yield significant performance and administrative advantages, is introduced. How this technology will evolve to complement the emerging fiber-based network, providing timely, ubiquitous wire pair transmission capabilities at basic rate, primary rate, and above is examined     

A safe transmission line for MRI

Magnetic resonance imaging (MRI) has been established as a reliable and safe imaging method for the human body. However, electric conductors, such as cables situated near or in the human body, should be avoided because induced currents in the cables can cause hazardous heating in the surrounding tissue. In this paper, a new principle for the design of a transmission line is introduced and demonstrated, which is capable of avoiding dangerous heating of cables. The principle is based on transformers placed along the line, splitting the long line into several short not resonant and thus safe sections. A transformer design is introduced along with the theoretical aspects for both the avoidance of the undesired induced currents and the reduction of signal attenuation. Furthermore, the design fulfills the geometrical requirements of the side lumen of a standard catheter. Matching networks, whose elements are determined by power matching, are used to reduce signal attenuation by the transformers. A prototype was built to validate both theory and the simulations. As demonstrated in this work, it is possible to build safe transmission lines for MRI, making applications such as active catheter tracking possible. We expect that even new applications, such as safe intravascular imaging will be possible in a safe manner in the future.     

Temporal skew and mode conversion management in differential pairs to 15 GHz

When used with emerging data-rates of 10 GHz and above, some standard transmission line length matching methods are shown to make mode conversion worse than without length matching. A new methodology for temporal skew management to preserve signal integrity in differential microstrip pairs to 15 GHz is proposed and validated through simulation.     

一种行波管高效率输能匹配结构的场分析

行波管的输能结构性能直接影响整管的效率与工作带宽,对输能结构的阻抗进行调匹配是十分必要的,一种实用的方法是在螺旋线末端加一个匹配筒来调匹配,但这种方法在理论层面还缺乏深入的研究。本文设计了一个带匹配筒的螺旋线行波管同轴型输能结构,用HFSS软件计算了引入匹配筒前后输能结构中的电磁场分布,从场的角度分析了匹配筒在输能结构中的作用机理,并给出了调匹配时应注意的条件。进一步,在优化匹配筒结构的基础上拉松末端两圈螺旋线,在12~18GHz的频段内实现电压驻波比低于1.23,对于行波管输能结构的设计有一定的参考意义。     

基于Simcenter 3D&1D对某车载雷达翻倒机构进行设计

本文根据某车载雷达翻倒机构的设计要求,对翻倒机构结构进行了设计、分析,对液压传动部分进行设计计算,最后基于Simcenter3D&1D多学科联合仿真软件对相关设计参数及指标进行仿真分析及验证。     

Exact moment matching model of transmission lines and applicationto interconnect delay estimation

Moment matching methods are widely used in delay estimation of interconnects modeled as transmission line networks. In this paper, we analyze the contribution of a transmission line to the moments of a resistor-transmission line-capacitor (R-T-C) network and provide a method to form a lumped moment matching model of the line. When the transmission lines are replaced by their pth order moment matching models, the network is transformed into a lumped R-L-C network such that these two networks have identical moments up to the order of p for each corresponding output node voltage. We also provide a recursive formula to compute the moments of the R-L-C network so that the moment matching techniques can be efficiently used in the delay estimation     

基于Census变换和多扫描线优化的半全局立体匹配算法

为了解决局部匹配算法误匹配率高的问题,提出 一种基于AD-Census变换和多扫描线优化的半全局匹配算 法。首先,通过绝对差AD算法与Census变换相结合作为相似性度量函数计算初始匹配代价, 并构建动态交叉域聚合 匹配代价;然后在代价聚合计算阶段,将一维动态规划的代价聚合推广到多扫描线优化,利 用上下左右四个方向逐 次扫描进行匹配代价聚合的计算,并引入正则化约束以确保匹配代价聚合的一致性,大大减 少初始代价中的匹配异 常点;最后,运用简单高效的胜者为王策略选出像素点在代价聚合最小时对应的视差,并在 视差细化阶段,采用左 右一致性检测和抛物线拟合方法进行后续处理以提高立体匹配的正确率。实验结果证明,该 算法可获得高匹配率的视差图并且耗时较少。