Comments on "Wave Propagation on Nonuniform Transmission Lines" (Letters)

It is shown that the solutions for wave propagation on a nonuniform transmission Iine, recently proposed by Bergquist, are alternative forms of, or easily derivable from, the results of Protonotarios and Wing, given earlier.     

Uniform Multimode Transmission Lines (Short Papers)

A consistent normal-mode theory for coupled uniform transmission lines is developed which properly accounts for the fact that some propagation constants may be equal. Explicit responses are calculated. The results are interpreted in terms of transmission-line networks which consist of simple lines and which are coupled via conductor sharing.     

Multilayer Microstrip Transmission Lines (Short Papers)

A method used to treat covered microstrip is extended to multilayer microstrip. Detailed results are obtained for the general three-layer problem. Series expansion and term-by-term integration are used to obtain a closed form expression for the Green's function. Matrix methods are then used to obtain the characteristic impedance. Data obtained agree closely with experiment.     

Normalized Impedance Graphs for Exponential Transmission Lines (Short Papers)

Sign errors in an existing closed form solution for the reflection coefficient along an exponentially tapered transmission line have been corrected and the solution has been modified by the use of electrical line length. This allows useful graphs for the input impedance of the tapered line to be computed which are normalized with respect to frequency and system impedance. The graphs clearly demonstrate both the broad-band and narrow-band properties of the tapered line.     

Multiconductor Transmission Lines and the Green's Matrix (Short Papers)

It is shown that the study of arbitrarily terminated multiconductor transmission lines which may in general be lossy and subjected to excitation applied at an arbitrary point along the lines, may be effectively performed with the aid of the appropriate Green's matrix. The procedure is illustrated using the Chipman method of impedance measurement as well as coupled microstrip lines.     

Propagation Along Transversely Inhomogeneous Coaxial Transmission Lines (Short papers)

Numerical "shooting" methods are employed in obtaining the dispersion curves of a coaxial waveguide loaded with a radially inhomogeneous dielectric. The utility of this technique is tested by comparing results with known analytical solutions. The method is also used to find the dispersion curves of a coaxial waveguide loaded with a radially Gaussian-distributed plasma.     

Higher Order Mode Cutoff in Polygonal Transmission Lines (Short Papers)

This paper provides an analytical solution to the problem of determining the cutoff wavelength of the first higher order mode in any transmission line having as its conductors a pair of coaxial, similar, similarly oriented regular polygons. The method is based on the cross-sectional resonance technique. It is shown that, under certain circumstances, the requirement that the polygons be coaxial can be relaxed and a solution still obtained in this way.     

Open-End and Edge Effect in Microstrip Transmission Lines (Short Papers)

An empirically derived relation is reported which accurately describes the open-end effect in microstrip transmission lines on alumina substrates. This empirical equation was used to describe the edge-correction term in Wheeler's general expression for the characteristic impedance for wide lines. It is shown that with this modification there exists a distinct crossover (w/h /spl ap/ 1) between the narrow- and wide-line approximations.     

Resolution of the Paradox Concerning Energy Flow on Nonlinear Transmission Lines (Short Papers)

The energy relations and the constitutive relations pertaining to a nonlinear transmission line are examined in detail. It is concluded that mathematical models which have been used in certain studies and which lead to the paradox concerning energy dissipation in the shock front are inadmissible. Correct models are free from such paradoxes. The work leads to the formulation of the hypothesis of realization: it is impossible to realize a continuous loss-free transmission medium which would be characterized by nonlinear distributed inductance L(I) and capacitance C(V), unless the medium is dispersive.     

Step Response of Lossless Nonuniform Transmission Lines with Power-Law Characteristic Impedance Function (Short Paper)

The step-response waveform of the Iossless nonuniform transmission line possessing a characteristic impedance function Z/sub c/(x)= Z/sub 0/(1 + eta x)/sup 2n/, n = 0,1,2,..., is deduced. The simple and closed-form solutions should be useful for pulse transient analysis involving nonuniform transmission lines.     

Design of Optimum Acoustic Surface Wave Delay Lines at Microwave Frequencies (Short Papers)

Optimum procedures for designing microwave acoustic surface wave delay lines are given. Combined beam steering fraction loss curves are provided as a function of the basic material parameter, the slope of the power flow angle, to allow optimum choice of material for a given application. Methods for designing uniform periodic interdigital transducers including finger ohmic loss, lossy tuning elements, and parasitic capacitance have been extended to account for beam steering and diffraction.     

On Uniform Multimode Transmission (Short Papers)

In a recent short paper, a method for constructing solutions to the classical uniform multiwire transmission-line equations was given which was intended to include the case of partial eigenvalue degeneracy. This development appears to be incorrect and a correct development will be given. In addition, a complete method for constructing the matrix chain parameters of a section of line will be presented.     

Dielectric Loss in Microstrip Lines (Short Papers)

A new technique is presented for calculating dielectric loss in microstrip lines. Numerical results for several different substrates are included. These are compared with other available results and experimental data.     

The Piezoelectric-Magnetoelastic Wave Propagation through the Conducting Plate in a Composite Medium (Short Papers)

The piezoelectric and magnetoelastic surface wave propagation through a composite layered structure of one piezoelectric and another magnetoelastic media is considered with a metal plate placed in between them. The dispersion relations have been derived and numerically computed. Thereafter, the field distributions are evaluated. These results may find usefulness for the realization of nonreciprocal acoustic surface wave devices.     

Understanding Soliton Wave Propagation in Nonlinear Transmission Lines for Millimeter Wave Multiplication

In this paper, soliton propagation in nonlinear transmission lines (NLTLs) periodically loaded with symmetric voltage dependent capacitances is studied. From the lumped element equivalent circuit of the line we have analyzed the influence of nonlinear shunt reactances on soliton propagation characteristics. It is shown that by increasing the non linearity of the C–V characteristic, a faster separation of input signal into solitons is achieved. The fact that frequency multiplication in NLTLs is governed by soliton formation makes the results of this work relevant to understand the influence of nonlinear loading devices on multiplier performance. Since a heterostructure barrier varactor (HBV)-like voltage dependent capacitance has been considered for the nonlinear devices, this study can be of interest for the design of millimeter wave frequency multipliers loaded with HBVs.     

Useful Matrix Chain Parameter Identities for the Analysis of Multiconductor Transmission Lines (Short Papers)

By utilizing state variable theory, certain useful matrix identities involving submatrices of the chain parameter matrix for a multiconductor transmission line are shown. These identities are extensions of familiar properties associated with two-conductor lines to multiconductor lines and are used to formulate the complete solution for the terminal currents when the line is terminated by linear networks. The identities allow a simplified solution for these currents and reduce numerous redundant time-consuming matrix multiplications. In addition, the correspondence between familiar terms for the two-conductor case and the multiconductor case is shown.     

Field Propagation in an Open-Beam Waveguide (Short Papers)

A new method is described for the investigation of the open-beam waveguides, which may be applied even when the optical elements are not inserted in absorbing screens.     

Loss Calculations of Coupled Microstrip Lines (Short Papers)

Loss calculations have been performed to yield useful data relevant to the complementary odd and even modes propagating along a pair of identical coupled microstrip lines. The calculations are based on methods applied to the single-line case and indicate substantial differences in attenuation occurring between the odd and even modes for particular geometries.     

Magnetostatic Forward Volume Wave Propagation-Finite Width (Short Papers)

The infinite radiation resistance encountered at the low end of the magnetostatic forward volume wave frequency band for a YIG layer of finite width is avoided by employing a physically justifiable low frequency cutoff value higher than that for which radiation resistance would be infinite. Radiation reactance and insertion loss then can be calculated and are found to be relatively insensitive to the choice of the cutoff frequency, except for frequencies very close to cutoff. Beam spreading considerations determine the cutoff frequency.     

The Method of Series Expansion in the Frequency Domain Applied to Multidielectric Transmission Lines (Short Papers)

In this short paper a method of expanding the phase constant and the field of a multidielectric transmission line as a power series of the frequency is developed. The method provides a theoretical justification for the widely used "static" approximations and indicates the reason why their accuracy is frequently good. This expansion may also be useful for estimating an upper limit to the frequency band in which the dispersion does not exceed a specified value. A numerical example is included.