Generalised theory of uniform transmission lines

The conventional circuit theory of uniform two-conductor transmission lines (TEM mode) assumes that at any cross-section the current in one conductor is equal and opposite to that in the other. This is not necessarily true, and even when it is true the resulting theory does not permit solution of some simple problems such as evaluation of the voltage difference between two points on the same conductor. The author presents a more general circuit theory which does permit solution of such problems and does not demand current balance. He shows that when there is current imbalance the expressions for voltage contain a term which depends linearly upon line length, as well as the familiar hyperbolic function terms     

Theory of nonreciprocal and nonsymmetric uniform transmission lines

A nonreciprocal and nonsymmetric transmission line is one which has different line parameters for waves propagating in opposite directions. Such a concept emerges in problems of electromagnetic wave propagation in layered structures of biisotropic (nonreciprocal chiral) media. It is shown that the well-known transmission-line formulas can be generalized for the present transmission line     

An accurate calculation of uniform microstrip transmission lines

An analytical program for calculating the field distribution about a microstrip transmission line bounded by a shielding wall is used to calculate the impedance, velocity, and attenuation parameters. The program input parameters are the dimensions of the strip and shielding wall and the relative dielectric constant of the substrate material. The field distribution about the strip is integrated to find the charge density on the strip and walls with and without the dielectric substrate. From these two calculations, the relative velocity and impedance can be calculated.     

Driving point function synthesis using uniform transmission lines

It is shown that the two classes of driving point functions realized by Wyadrum and by O'Shea, using uniform transmission lines, are identical and further that these driving point functions may always be cascade synthesized. An alternative set of necessary and sufficient conditions for this class of driving point functions is given.     

Field coupling to nonuniform and uniform transmission lines

We study time-domain and frequency-domain responses of nonuniform and uniform transmission lines excited by incident electromagnetic waves. Externally excited uniform transmission lines permit closed-form solutions in terms of inverse chain matrix, whereas nonuniform lines cannot be analytically solved, in general. We adopt a method of equivalent cascaded network chain as the method of solving the latter situation. Useful and compact expressions for the load currents induced at terminal loads are derived. To confirm the validity of this method and the forcing terms, theoretical and experimental results of coupling calculations for a few typical (uniform/nonuniform) line geometries, relevant in the EMC field, are presented and discussed     

Cutoff frequencies of transmission lines consisting of pair ofcylinders

The paper presents a method of evaluation of cutoff frequencies of higher-order modes of transmission line of parallel cylinders by transforming them into a parallel plate configuration using cotangent hyperbolic transformation. Application of the method of finite difference to the weighted Helmholtz equation leads to a set of simultaneous equations. The eigenvalues related to cutoff frequencies are determined from the characteristic equation expressed in terms of matrices obtained from the simultaneous equations. Numerical data are presented     

Approximation of a nonuniform transmission line by a cascade of uniform lines

It is shown that an arbitrary nonuniform transmission line may be approximated by a cascade of commensurate uniform lines. In general, a small number of lines is sufficient to obtain a good approximation, and hence the method should prove useful, both in the analysis of arbitrarily tapered lines and in the study of their properties.     

Natural frequencies of circular disks

The natural frequencies or the singularity expansion method (SEM) poles are computed for circular disks. We treat the acoustically soft disk, i.e, the Dirichlet boundary condition, and the perfectly conducting disk. The poles are found by an application of theT-matrix method by searching the zeros of a determinant. The poles associated with the first values of the azimuthal indexmare shown in both cases, and numerical values are given in tables and figures. The internal resonances are also computed for the thin oblate spheroidal cavity and comparisons are made with the thin circular cylindrical cavity.     

Metal-insulator-semiconductor transmission lines

This paper investigates the one-dimensional metal-insulator-semiconductor transmission line. It develops closed-form expressions for equivalent-circuit parameters, compares them to exact calculations, and explores their limitations. It also investigates the usual assumption of single-mode propagation and shows that, in certain fairly common circumstances, the fundamental mode of propagation becomes so lossy that it can no longer be considered to be the dominant propagating mode     

Directional coupler for gigahertz frequencies, based on the coupling properties of two planar comb transmission lines

The principles of operation are given for a directional coupler based on the coupling properties of two interleaved planar comb transmission lines. It is shown that this arrangement leads to a departure from a contradirectional coupling mechanism. Results are given for an X band ?3 dB coupler, and the performance and manufacturing methods are compared with those of other high-frequency coupler designs.     

Through-silicon-chip transmission lines

Through-chip transmission lines connecting the frontside and backside of high-resistivity wafers are fabricated using bulk-micromachining and backside metal patterning. Experimental results illustrate the feasibility of low-loss through-chip microstrips and coplanar waveguides for innovative integration concepts of radio-frequency and microwave systems in silicon technology     

Millimeter wave attenuation prediction using a piecewise uniform rain rate model

A piecewise uniform rain rate distribution model is introduced as a quasi-physical model of real rain along earth-space millimeter wave propagation paths. It permits calculation of the total attenuation from specific attenuation in a simple fashion. The model predications are verified by comparison with direct attenuation measurements for several frequencies, elevation angles, and locations. Also, coupled with the Rice-- Holmberg rain rate model, attenuation statistics are predicated from rainfall accumulation data.     

Cutoff frequencies of uniform waveguides of regular polygonal cross section

This letter deals with the problem of calculating the cutoff frequencies of hollow piped waveguides of regular polygonal cross section. By conformally transforming the given cross section onto a unit circle, the boundary conditions can be identically satisfied; however, the transformed partial differential equation must be solved by approximate procedures. The results are considered excellent, demonstrating remarkable agreement with the exact values in the case of square and circular cross sections. Only TM modes are considered in the present study; TE modes can be treated in a similar manner.     

Uniform and piecewise uniform lattice vector quantization formemoryless Gaussian and Laplacian sources

Lattice vector quantizer design procedures for nonuniform sources are presented. The procedures yield lattice vector quantizers with excellent performance and retaining the structure required for fast quantization. Analytical methods for truncating and scaling lattices to be used in vector quantizations are given, and their utility is demonstrated for independent and identically distributed (i.i.d.) Gaussian and Laplacian sources. An analytical technique for piecewise linear multidimensional compandor designs is evaluated for i.i.d. Gaussian and Laplacian sources by comparing its performance to that of the other vector quantizers     

Overview of quasi-planar transmission lines

A number of quasi-planar transmission lines are reviewed in terms of the general propagation characteristics including useful features, precautions in practice, and some design information. Transmission lines discussed here include coplanar waveguides, finlines, suspended stripline, and microslab waveguides. Attenuation characteristics of some of these lines are compared. The problem of discontinuity characterizations is discussed     

Simulink simulation of transmission lines

MATLAB can manipulate and invert large matrices and can be used in many numerical applications. MATLAB's capabilities can be extended with a recent addition called Simulink, a program which is normally used in the analysis and synthesis of modern control systems. Simulink, now incorporated into MATLAB, can also be used to analyze distributed transmission lines. Hence, it can be directly used in the analysis and design of microwave, electric power, and VLSI networks. In addition to demonstrating its wider applicability, we include several examples that are normally described in books or papers directed to the study of pulse propagation along transmission lines     

CHARACTERISTICS OF MICROSTRIP TRANSMISSION LINES

An efficient hybrid field solution to microstrip transmission lines is presented byusing SLE and SLM modes in spectral domain.It by-passes the lengthy process of formulatingthe determinant equation for the unknown propagation constant.Compared with spectral domainadmittance approach,this method is clear in both physical and mathematical senses and may beapplied to a variety of structures.     

试论特高压共走廊输电线路电磁耦合分析及改善措施

在雷电天气中,雷击现象会引发特高压共走廊输电线路的电磁耦合,进而影响电力设备的正常使用.本文从电磁耦合的概念入手,对特高压共走廊输电线路的电磁耦合及改善措施进行分析和研究.     

Optimum buffer circuits for driving long uniform lines

The design of optimum buffer circuits for driving long uniform lines is discussed. Given a uniform line, the size of the buffer driving the line, and the value of the capacitive load driven by the line, the problem considered consists of determining the type, number, and position of buffers that minimize the delay in the line. A variation of this problem that is also considered consists of minimizing the delay in the line when the area occupied by the buffers is constrained; this leads to the solution of the problem of minimizing the delay in driving a pure capacitive load under buffer area constraint. The optimal solution is formally developed, and some very good approximate solutions that can be obtained via simple computations are presented. It is shown that accepting a small increase in delay (of usually 5% over the minimum) can lead to a significant (about 50%) decrease in the area occupied by the buffers. Design curves that allow the reader to determine the optimum buffers with little effort are presented     

Surface losses in transmission lines

Two derivations of the loss parameter R, entirely from wave considerations in the presence of a metallic interface, are presented. R, which represents surface losses, occurs in transmission line equations for propagation of the voltage across the plates and of the current in the plates. Explanation of the surface losses involves some radiation of the interior fields into the metallic surfaces that absorb electromagnetic energy, and that ultimately convert it into ohmic losses (heat). Although the approach may restrict the derivation to a planar interface, i.e., to a parallel-plate transmission line, that restriction is not so essential that it cannot be softened