Multimode network analysis of planar transmission lines

An alternative approach for the full wave analysis of single or coupled planar transmission lines is presented. Following the proposed approach, a multiple (or single) transmission line structure is viewed as series of stacked (or single) transverse discontinuities in a parallel plate waveguide. As a consequence, both top and side coupled structures can be studied. Each individual discontinuity is described in terms of a multimode equivalent network representation. The complete cross section of the planar transmission line structure is then described in terms of a transverse equivalent network and a simple transverse resonance technique is then used to obtain the dispersion behavior, the modal field of the structure, and the characteristic impedances. The multimode equivalent network representations of the individual discontinuities used in this paper have been derived elsewhere and are given in terms of impedance or admittance matrices that are essentially independent from frequency. As a result, they need to be computed only once for each given geometry thus leading to codes that are computationally very efficient     

Improved quasi-TEM spectral domain analysis of boxed coplanarmulticonductor microstrip lines

A very efficient quasi-TEM analysis of multistrip transmission systems embedded in a layered medium is presented. The number of conductors and substrates is arbitrary, and the whole structure is assumed to be enclosed in a rectangular set of boundary conditions. The analysis makes use of the Galerkin method in the spectral domain. Chebyshev polynomials with edge conditions are used as basis and test functions for the strips' free charge distribution. This standard technique is considerably enhanced by using two alternative procedures to accelerate the computation of the entries of the Galerkin matrix. Extremely accurate results for a multistrip system, including the charge distribution, can then be obtained on a PC computer in a short time     

An efficient numerical spectral domain method to analyze a largeclass of nonreciprocal planar transmission lines

Presents an efficient numerical application of the Galerkin method in the spectral domain (SD) to the analysis of striplike/slotlike coplanar transmission lines embedded in a bianisotropic multilayered medium. The method is based on obtaining the spectral dyadic Green's function by the equivalent boundary method (EBM), a suitable third order extraction technique of the asymptotic behavior of the Green's dyad, an enhanced numerical integration scheme, and the use of an adequate contour integral method for searching zeros in the complex plane. This method, namely the SD-EBM, has been found to be very suitable for analyzing transmission lines with semiconductors and/or ferrites magnetized at an arbitrary direction, including the study of magnetostatic wave propagation phenomena     

Accurate quasi-TEM spectral domain analysis of single and multiplecoupled microstrip lines of arbitrary metallization thickness

The quasi-TEM spectral domain approach (SDA) is extended to rigorously and efficiently analyze single and multiple coupled microstrip lines of arbitrary metallization thickness. The charge distributions on both the horizontal and vertical conductor surfaces are modeled by global basis functions. This results in a relatively small matrix for accurate determination of the line parameters of coupled thick microstrips. A convergence study is performed for the results of a pair of coupled lines with crucial structural parameters to explore the conditions for obtaining reliable solutions using the technique. Results for thick microstrips are validated through comparison with those from available measurements and another theoretical technique. The soundness of the technique is further demonstrated by looking into the trend of the results obtained by a simplified model in which the structural parameters are pushed, step by step, to the numerical extremities. Variations of circuit parameters of a four-line coupled microstrip structure due to the change of finite metallization thickness are presented and discussed     

Design and analysis of a wireless monitoring network for transmission lines in smart grid

In order to timely and precisely locate a problem over the power lines, the control center needs to monitor the status of the transmissionlines and the towers. In this paper, we design such a monitoring network by taking advantage of the existing optical fiber composite overhead ground wire (OPGW) alongside the transmission lines. Because it is not cost‐effective to have gateway access to the OPGW for every transmission tower, we propose to deploy a multi‐hop wireless sensor network in between two sparsely deployed neighboring OPGW gateways. We mainly study the power allocation for the data transmission of the wireless sensors because of the assumption that such sensors are powered by green energy and a battery with limited capacity for easy deployment and maintenance. Specifically, we propose several centralized schemes with different objectives, for example, the minimum power usage and fast computation. We also propose a distributed scheme so that the sensors can be even more energy efficient dealing with dynamic traffic in field operations. Moreover, we analyze the centralized schemes to study their pros and cons. We also conduct a case study for the distributed scheme to demonstrate its feasibility in field operations. Copyright © 2015 John Wiley & Sons, Ltd.     

Matched-termination network for multiple parallel transmission lines

A matched-termination network for multiple parallel transmission lines is capable of absorbing all the possible TEM propagation modes without reflection. A general expression is presented for such a network when the transmission lines are lossless. If, in addition, the propagation velocities are all equal, a network can be designed by inspection.     

Short-time spectral and autocorrelation analysis in the Walsh domain

A short-time dyadic autocorrelation function (dacf) and a short-time Walsh energy spectrum of the first kind are defined in the Walsh-Fourier domain. The "natural" choice of the short-time functions does not lead to a Walsh-Fourier transform pair (dyadic Wiener-Khintchine theorem), and thus a second kind of short-time dacf and short-time Walsh energy spectrum are defined as the Walsh-Fourier transforms of the first kind. This leads to a meaningful and convenient Walsh transform pair between the first short-time Walsh energy spectrum and the second short-time dacf. The measurement procedures for both kinds of functions are discussed, and the mean values of these short-time functions are shown to be related to the corresponding long-time functions.     

Lossy transmission lines: time domain formulation and simulationmodel

The time domain quasi-TEM equations for lossy transmission lines with R, L, C, and G parameters is reformulated and solved to relate directly the currents and voltages at the line terminations, at present and past times. This allows a computer model to be set up for simulating circuits with nonlinear terminations in the time domain using general circuit simulators. This formulation describes propagation of two dynamic forward and backward waves and is the extension of the method of characteristics to the lossy case. Distortion and impedance changes are generated by finite convolutions with past history information at the line terminations. For constant R, L, C, and G, and for a skin effect approximation, the kernels of Green's functions for these convolutions are derived as analytic expressions     

巡线LiDAR多通道光谱图像异常识别技术

联合GPS、ISN、LiDAR、测距机等, 构建超POS信息;计算最小视场分辨率、像元数、焦距等选择相机;将POS采集系统与相机组合成LiDAR多通道光谱图像异常识别系统.采用多通道匹配融合法融合紫、红外、彩色图片, 基于Hough变换, 通过同族容器归纳法确定疑似故障点.运用Hough变换、免疫遗传Snake、最小二乘法解析椭圆形貌, 解决绝缘子异常识别问题.工程实验表明, 该系统平均探测精度是82.4%, 优于直升机与人工平均值24.05%, 是一种高效率的智能电网巡线排查手段.     

多导体传输线瞬态响应研究

针对多导体传输线瞬态响应的无源性问题,提出了基于集总等效源模型的多导体传输线瞬态响应模型. 从外场激励下的多导体传输线的频域电报方程解出发,将外场在传输线上激励的分布电压源和电流源与传输线指数矩阵解耦,建立了集总等效电压源和电流源模型. 为避免复杂的傅里叶反变换及卷积运算,推导了集总源模型的时域递推方程. 在此基础上,采用时域有限差分法建立了端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应离散递推方程. 通过对无损传输线的仿真对比,验证了方法的有效性. 最后,对端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应进行了试验和仿真分析.     

多导体传输线瞬态响应研究

针对多导体传输线瞬态响应的无源性问题,提出了基于集总等效源模型的多导体传输线瞬态响应模型. 从外场激励下的多导体传输线的频域电报方程解出发,将外场在传输线上激励的分布电压源和电流源与传输线指数矩阵解耦,建立了集总等效电压源和电流源模型. 为避免复杂的傅里叶反变换及卷积运算,推导了集总源模型的时域递推方程. 在此基础上,采用时域有限差分法建立了端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应离散递推方程. 通过对无损传输线的仿真对比,验证了方法的有效性. 最后,对端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应进行了试验和仿真分析.       

Transient analysis of TEM transmission lines

The method of characteristics is suitable for digital computer solution of TEM transmission lines. Using numerical methods, losses can be taken into account. Interconnected transmission-line networks, nonuniform lines, and nonlinear lines are considered.     

Static analysis of V transmission lines

A static analysis of V-shaped transmission lines is performed using a moment method formulation. Measurements were performed on a sample, and the validity of the theoretical results is verified by the experimental data. Characteristic impedance and propagation velocity are found to be strongly dependent on the angle parameter. Comparison with microstrip indicates a lower characteristic impedance and higher effective permittivity for V transmission lines. For multiple lines, the shape of the ground reference leads to lower coupling coefficients and lower mutual inductance and capacitance between adjacent lines     

多导体传输线瞬态响应研究

随着多导体传输线内各导体之间间距的减小, 导体之间的近邻效应对传输线的分布参数和传输特性的影响越来越大.为此, 我们针对三种典型的传输线结构, 分别建立了基于矢势有限元方法分析的多导体传输线的模型, 并分析了近邻效应对磁通密度和分布电感的影响.利用提出的方法计算了同轴传输线的单位长度分布电感, 并将它与采用解析方法得到的结果进行比较来证明该方法的正确性.计算双线传输线在不同间距时的单位长度电感, 与理论分析得到的结果相比较验证了导线间距越小, 近邻效应对单位长度电感的影响越大.最后, 计算考虑了近邻效应的耦合微带线的电感矩阵, 并将它与其他不考虑近邻效应的方法得到的结果相比较, 说明近邻效应对传输线电感矩阵的影响.     

Transient analysis of lossless transmission lines

The method of characteristics provides a simple analytic solution for the transient analysis of a uniform, lossless transmission line. The interpretation of this solution in terms of equivalent network of the input and output behavior of the transmission line leads to an efficient algorithm which yields not only the input and output responses but also the incident and reflected waves. This method is superior in both speed and accuracy to the familiar method of integrating the differential equations that describe a lumped LC model of the line; but it is not applicable to lossy lines.     

Quasi-static analysis of shielded planar transmission lines withfinite metallization thickness by a mixed spectral-space domain method

A new method to analyze shielded planar transmission lines with finite metallization thickness is described. It is based on a mixed spectral-space domain representation of the Green's function. The method allows the accurate determination of the static parameters of the transmission line with great efficiency as compared to methods available in the literature. Several numerical examples are shown on single and coupled planar transmission lines     

Monitoring power transmission lines using a wireless sensor network

Power transmission is the bulk transfer of electrical energy from power plants to sub‐stations. A wireless sensor network is a promising technology for transmission line monitoring due to its low cost, easy installation, large‐scale coverage, and fault tolerance characteristics. A wireless sensor network is application‐specific; therefore, we investigate the new features and requirements of the wireless sensor network used in transmission line monitoring. Then, we propose an efficient wireless sensor network framework, which includes a clustering algorithm to simplify network management and to balance the network's energy consumption and a hybrid media access control (MAC) (H‐MAC) protocol to handle traffic variability. The framework takes advantage of the features of network topology and traffic pattern to optimize the protocols' performance on real time and energy efficiency. The results indicate that the H‐MAC shows a significant improvement in the network's reliability, real‐time performance, and energy efficiency, and the cluster hierarchy can balance the network's energy consumption. Furthermore, the cluster hierarchy also prolongs the network's lifetime. Copyright © 2014 John Wiley & Sons, Ltd.     

Rigorous analysis of planar MIS transmission lines

The realisation of distributed microwave integrated circuits can be expected by using very low phase velocity propagation modes on MIS and Schottky planar transmission lines. Up to now, the frequency behaviour of such lines has been obtained by using analytical models. We present a rigorous analysis of a MIS microstrip line, the validity of which is testified by comparison to experimental values.     

Time-domain analysis of lossy coupled transmission lines

A novel method based on numerical inversion of the Laplace transform is presented for the analysis of lossy coupled transmission lines with arbitrary linear terminal and interconnecting networks. The formulation of the network equations is based on a Laplace-domain admittance stamp for the transmission line. The transmission line stamp can be used to formulate equations representing arbitrarily complex networks of transmission lines and interconnects. These equations can be solved to get the frequency-domain response of the network. Numerical inversion of the Laplace transform allows the time-domain response to be calculated directly from Laplace-domain equations. This method is an alternative to calculating the frequency-domain response and using the fast Fourier transform to obtain the time-domain response. The inversion technique is equivalent to high-order, numerically stable integration methods. Numerical examples showing the general application of the method are presented. It is shown that the inverse Laplace technique is able to calculate the step response of a network. The time-domain independence of the solution is exploited by an efficient calculation of the propagation delay of the network