Multiple microstrip lines on a multilayered cylindrical dielectricsubstrate on perfectly conducting wedge

The quasi-TEM characteristics of a class of cylindrical microstrip lines are rigorously determined. The class of microstrip lines considered consists of multiple infinitesimally thin strips on a multilayered dielectric substrate on a perfectly conducting wedge. Expressions for the potential distribution inside and outside the dielectric substrate, charge distribution on the strips, and capacitance matrix of the microstrip lines are derived. The problems of a microstrip line on a cylindrically capped wedge and on a cylindrical dielectric substrate on perfectly conducting core are also considered as special cases. Sample numerical results based on the derived expressions are given and discussed     

New scattering matrix parameter formulas for transmission modedielectric resonator filter networks

New scattering matrix parameter formulas are presented for the fundamental TE_01δ mode of a cylindrical dielectric resonator, coupled with two parallel microstrip transmission lines     

Full-Wave Analysis of Inside Cylindrical Microstrip Lines by Finite Element Method

In this paper, a full-wave analysis using finite element method is presented to investigate the dispersion characteristics of inside cylindrical microstrip lines, which are essential to the design of some conformal microstrip circuits in millimeter wave bands. Numerical results of frequency-dependent effective dielectric constants are given for different structural dimensions and dielectric constants of substrate. Some useful conclusions are derived for the design of the special conformal microstrip lines.     

Analysis of cylindrical microstrip lines using the discrete mode matching method

This letter presents an extension of the discrete mode matching (DMM) method to analyze microstrip lines conformed on cylinders. The DMM is well suited to the analysis of multilayered structures, since the fields must be only sampled at the interfaces between the dielectric layers. For the case of cylindrical microstrip lines, the structure is discretized only along one direction, whereas the analytical solution is obtained in the other with the Green's functions calculated using a full-wave equivalent circuit. The mathematical formulation of the present extension is given in this letter, followed by its application to compute the propagation constants for cylindrical microstrip lines.     

Dissipation Loss Effects in Isolated and Coupled Transmission Lines

This paper describes a computer-aided analysis of dissipation losses in uniform isolated or coupled transmission lines for microwave and millimeter-wave integrated-circuit applications. The analysis employs a quasi-TEM model for isolated transmission lines and for the even- and odd-mode transmission lines associated with coupled-line structures. The conductor and dielectric losses are then related to equivalent charge density distributions, which are evaluated using a method-of-moments solution. The transmission lines treated by this analysis may contain any number of Iossy conductors and inhomogeneous dielectrics, consisting of any number of different homogeneous dielectric regions. A development is provided to explicitly relate the four-port terminal-electrical performance of directional couplers to evaluated even- and odd- mode loss coefficients. Examples of evaluated losses are presented in graphical form for isolated lines of inverted microstrip and trapped inverted microstrip and edge-coupled microstrip with a dielectric overlay. The analysis accuracy has been confirmed using microstrip and coplanar waveguide configurations. A comparison is made of the total loss characteristics for microstrip, coplanar waveguide, inverted microstrip, and trapped inverted microstrip. Calculations are compared with measurements for the coupled-line structure. Accuracy of the solution and suggested refinements are discussed. Five computer programs are documented.     

Unified Approach to Solve a Class of Strip and Microstrip-Like Transmission Lines

This paper presents a unified analytical approach to solve a class of shielded strip and shielded microstrip-like transmission lines with multilayer dielectrics under TEM-wave approximation. The analysis makes use of the variational technique in the space domain combined with the "transverse transmission line" method. Expressions are derived for the capacitance of a single line, coupled two-line and coupled four-line structures. The same formulas can be used for a class of such structures by the substitution of a single parameter, namely, the admittance at the charge plane, which can be obtained using the standard transmission line formulas. Numerical results of two special structures, namely, the broadside-coupled suspended microstrip lines, and broadside-coupled inverted microstrip lines, using two suspended, dielectric substrates are included. The technique presented is the simplest compared to any other analytical procedures reported in the literature.     

Propagation Parameters of Coupled Microstrip-Like Transmission Lines for Millimeter-Wave Applications

A variational expression is derived for the propagation parameters of coupled microstrip-like transmission lines for millimeter-wave applications using the "transverse transmission line" method. Numerical results are presented for the coupled inverted microstrip lines, and for the coupled suspended microstrip lines. The effects of the top and sidewalls and also of the finite thickness of strip conductors on the even- and odd-mode impedances are studied. The use of a dielectric overlay in equalizing the even- and odd-mode phase velocities is investigated.     

Effect of the Dielectric Anisotropy on the Propagation Properties of Microstrip Tapers with Height Variations

This paper deals with the design and application of nonuniform microstrip transmission lines on anisotropic substrates. A rigorous analysis is based on the use of Hertz vector potentials, moment method and transmission line theory to determine the dispersion characteristics of single and coupled tapered microstrip lines for accurate performance prediction. Results are presented for the main parameters providing the necessary information to design several devices on tapered microstrip, with variation on the strip width and dielectric height, for (M)MIC and antennas applications. A good agreement was observed with the results available in the literature for tapered lines on isotropic substrates.     

铁氧体介质基片微带线色散特性的研究

利用扩展的二维FD-TD方法研究了包含铁氧体介质的均匀微带线的色散特性.给出了铁氧体介质的厚度,微带线导带宽度以及铁氧体的外加恒磁场对其传输特性的影响.并对这类传输线在禁带附近模式容易传播的模式进行了讨论.     

Decoupling between two conductor microstrip transmission line

A numerical analysis of two-conductor transmission line with a rectangular notch in the dielectric between the strips is presented. Three media integral equations are derived and solved for the charge distributions. The decoupling between such two-conductor coupled microstrip transmission lines is investigated for asymmetric conductors. It is found that the coupling between two conducting lines can be reduced significantly by removing dielectric material between the lines which has a rectangular shape. For best decoupling, the width should be as wide as possible between the conducting lines but the depth should have an optimum somewhere in the base dielectric substrate     

Microstrip Transmission Line with Finite-Width Dielectric and Ground Plane (Short Paper)

Design data for microstrip transmission lines with finite-width dielectric and ground plane are presented. The characteristic impedance and velocity of propagation are tabulated from results of a moment-method solution of a quasi-TEM transmission-line model of this microstrip structure.     

Comparative study on the mutual coupling between different sized cylindrical dielectric resonators antennas and circular microstrip patch antennas

A systematic comparative study on the mutual coupling (S/sub 21/) between dielectric resonator antennas (DRAs) and microstrip patch antennas is presented. The mutual coupling between two cylindrical probe-fed DRAs is studied for different radius to height (a/L) ratios. It is found that the mutual coupling decreases with the radius to height ratio. Comparison between mutual coupling of probe-fed cylindrical DRAs and circular microstrip patch antennas with different dielectric substrates are also studied. The mutual coupling between DRAs is 2 dB stronger than between microstrip patch antennas when the patch is etched on a dielectric substrate of a dielectric constant close to the permittivity of the DRA. The mutual coupling of the circular patch antennas reduces with the dielectric constant of the substrate.     

Frequency dependent transmission characteristics of microstrip lines on the finite width substrate or near a substrate edge

An accurate hybrid mode analysis of microstrip lines on the finite width substrate or near a substrate edge including finite metallisation thickness is described. The frequency dependent solutions for the transmission characteristics of the microstrip lines are presented. An approach for avoiding the calculation of higher modes in a rectangular waveguide partially filled with a dielectric is also introduced. The results provide useful information for the design of high packing density millimetre wave MMICs.<>     

An Accurate Determination of Dielectric Loss Effect in Monolithic Microwave Integrated Circuits Including Microstrip and Coupled Microstrip Lines

For the first time, by a rigorous analysis, the performance of MIC planar transmission lines with Iossy substrates can be studied accurately. The generaf structural shape chosen for the analysis includes infinitely thin metallic strips embedded within the layers of homogeneous dielectric substrates. The rigor of the analysis was guaranteed by the assumption of the propagation of an electromagnetic hybrid wave (i.e., TE+TM) along tbe planar transmission lines. An efficient computation was, however, achieved by implementing the spectral domain approach as the basis for the analysis. To test the analysis, phase constants, characteristic impedances, and attenuations, due to dielectric losses, were computed for microstrip and coupled microstrip lines. The results obtained were compared with those given previously by the spectral domain analysis in which dielectric losses were not included directly [1]. The comparison showed an excellent agreement between the two theories for low-loss substrates. However, for Iossy substrates the present method is more accurate.     

Analysis of microstrip analogues of bandpass filters on one-dimensional photonic crystals

Structures composed of connected-in-series sections of microstrip transmission lines with different characteristic impedances and effective permittivities are analyzed. It is shown that such irregular microstrip structures are good analogues of 1D photonic crystals consisting of alternate dielectric layers with abrupt and diffuse interfaces. Behavior of transmitted and reflected waves is studied in a wide frequency band as a function of the design parameters of microstrip models. The results of a quasi-static numerical analysis of these structures agree rather well with experimental data. The results obtained can be used for a substantial improvement of characteristics of bandpass filters built on dielectric photonic crystals.     

Dispersion analysis of multilayer cylindrical transmission linescontaining magnetized ferrite substrates

Recently, there has been a growing interest in using cylindrical transmission lines that contain magnetized ferrite material in a variety of applications. In this paper, the finite-difference time-domain (FDTD) method (in cylindrical coordinates) and the spectral-domain analysis (SDA) are used to calculate the propagation characteristics of cylindrical transmission lines that contain magnetized ferrite material. The magnetization can be either in the longitudinal or azimuthal directions. Specifically, the cylindrical microstrip line, and the cylindrical coplanar waveguide printed on magnetized ferrite substrate are analyzed. Both the FDTD and SDA results are in very good agreement. In addition, the results are compared to those of planar structures by taking the radius of the substrate to be large enough such that the curvature effect is negligible     

Equivalent Capacitances for Microstrip Gaps and Steps

The excess charge density distribution near gaps and steps in microstrip transmission lines is calculated by the solution of singular integral equations. Data are presented for gaps in microstrips of width-to-substrate-thickness ratios of 0.5, 1.0, and 2.0 and relative dielectric constants ranging from 1.0 to 15.0. For steps in a microstrip line results are given for width-to-thickness ratio of unity, relative dielectric constants of 1.0 and 9.6, while the change of width-to-height ratio is from 0.1 to 10.0. The excess charges are calculated explicitly in relatively short computing times, and the results are believed to be accurate to within a few percent.     

Analysis of a Class of Cylindrical Multiconductor Transmission Lines Using an Iterative Approaclh

A class of cylindrical multiconductor transmission lines is theoretically analyzed, and useful parameters, e.g., characteristic impedance and effective dielectric constant, are derived. Discretization of the continuous functions and exploitation of the periodicity of the cylindrical structure lead to a discrete convolution which can be carried out numerically rigorously and efficiently using the FFT algorithm. An iterative technique is employed in the spectral domain to derive the solution of integral equations for the charge distribution. Numerical results are presented and compared with available data.     

Cryogenic performance of microstrip substrates

Measurements have been made, at very low temperatures (290 K-20 K), of the effective dielectric constants of a number of microstrip transmission lines fabricated on fibre-glass reinforced PTFE substrates.     

Microstrip transmission line analysis by the use of the least-squares collocation method

A simple method of analysis of microstrip transmission lines by the corner function method (eigenfunction approach) is presented. The inhomogeneous dielectric system of the microstrip is treated as a mixed boundary-value problem and is solved by the use of the least-squares collocation method. The results obtained by this method agree well with previous theoretical results and the method of analysis is much less laborious, simpler and faster.