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.     

Analysis and design of a leaky-wave EMC dipole array

An analysis of an electromagnetically coupled (EMC) dipole array is presented, in which a microstrip line is coupled to an infinite periodic linear array of microstrip dipoles, arranged perpendicular to the line. The spectral-domain immittance method is used to obtain the periodic Green's function for the two-layered structure, and the method of moments with a Galerkin testing procedure is then used to enforce the electric field integral equation (EFIE) on the line and the dipole within a unit cell of the structure to obtain the determinantal equation for the unknown leaky-wave propagation constant. One of the interesting features of this analysis is the path of integration in the complex plane used to compute the moment method reactions, which must be partly on the improper sheet for the m=-1 space harmonic when it radiates in the forward direction. Measured radiation patterns for a 10-element EMC dipole array are presented and compared with the corresponding theoretical ones     

Investigation of Crosstalk and Coupling Effects of Incident Plane Waves in Orthogonal Microstrips in High-Speed Integrated Circuits Using Full-Wave and Quasi-Static Methods

The crosstalk and coupling of the external fields on orthogonal microstrip transmission lines in different layers have significant effects on signal quality in MMIC and PCBs. In this paper the crosstalk is analyzed in detail using both full-wave and quasi-static methods. The used full wave method is mixed potential integral equation method of moment (MPIEMoM). Because of the weak coupling between lines, the effect of the incident plane-wave is studied by applying transmission line theory in a scattered voltage formulation uses quasi-TEM propagation model for each interconnection and the exact distribution of the incident electric field within the layers. Afterward, by using the predetermined lumped circuit model of the cross-region, the effect of coupling between two lines is calculated and then applied to terminal voltages in 1–20 GHz frequency range which results in the final terminal voltages.     

A Novel Bandpass Filter Made of the Microstrip with Cantor Substrates

In this paper, the microstrip line with fractal Cantor distributing substrates is investigated. Transmission matrix method is used to calculate the transmittance and reflectance. Comparing with periodic distributing substrates, the microstrip line with fractal Cantor distribution shows sharp resonances inside band gap. The resonances in somewhere split and form more peaks with increase of the number of generation. Based on the microstrip line with Cantor substrates, a novel bandpass filter is proposed. The filter has 8.8 % 3dB bandwidth and two transmission zeros, 0.27dB insertion loss. The effect of width of microstrip line and thickness of substrate on the filter properties are discussed too.     

Analysis of wraparound microstrip phased array by infinite arrayapproach

A moment method analysis of an infinite array of wraparound microstrip antennas fed with idealized current probes on a cylindrical body is presented. The integral equation is formulated through the use of periodic grounded dielectric slab Green's function. The method accounts for the blind angles and allows efficient computation of the reflection coefficient at all other angles. Illustrative results are given     

On the EMC dipole feed-line parasitic radiation

A rigorous analysis of the electromagnetically coupled microstrip dipole based on potential integral equations, Green's functions, and the moment method is presented. The computations of the antenna's radiated field using the steepest descent technique is then detailed, and the theoretical results are compared with experimental measurements in the X-band. By considering the feed as an antenna part, the excitation line parasitic radiation is shown clearly. Two possibilities to reduce this parasitic phenomenon are proposed. Also, it is shown that in any microstrip structure (one or two layers) excited by a microstripline, the feed parasitic radiation is nonnegligible     

Propagation Characteristics of a Microstrip Line Printed on a General Anisotropic Substrate

An analysis is presented for determining the propagation modes in a microstrip line printed on a substrate having both electric- and magnetic-type general anisotropies. An integral equation is derived for the unknown current distribution on the microstrip line. The kernel of this equation is a complicated 2x2 matrix function of the substrate anisotropy and of the substrate thickness. In order to determine the dispersion relations for the propagating waves, this integral equation is reduced into a finite system of linear equations by employing Galerkin's technique. Numerical results are given for several cases, and the effect of rotating the anisotropy axis in anisotropic substrates is investigated. The proposed method can be employed to compute the propagation characteristics of microstrip lines printed on anisotropic substrates.     

Periodic structures on coupled slot resonators in the grounding layer of microstrip transmission line

The spectrum of natural frequencies of the resonator has been calculated. The specified resonator includes a microstrip transmission line with discontinuity in the form of two rectangular coupled slot resonators in the grounding layer. Based on the above spectrum and using the transverse resonance method the scattering matrix of the principal wave of the microstip transmission line on this discontinuity was calculated. The scattering characteristic of the periodic structure consisting of a finite number of cells in the form of coupled slot resonators in the grounding layer of microstrip line indicates that with due regard for their mutual coupling the losses in the first stopband can be reduced by 3–5 dB as compared with the characteristic obtained by tandem connection of the scattering matrices of separate slot resonators in the grounding layer of microstrip line.     

Scattering by an infinite periodic array of microstrip elements

An analysis of the scattering by an infinite periodic array of microstrip disks is made using a Galerkin solution of a vector integral equation. The solution is examined for convergence and compared with theory and experiment. The solution is used to minimize the loss and maximize the bandwidth of the element in a reflectarray configuration.     

An integrated quasi-planar leaky-wave antenna

A new quasi-planar leaky-wave antenna is presented. It consists of microstrip line on one side of the substrate and uniplanar circuit on the other side placed in a partially opened waveguide. The leakage is produced by the excitation of the first higher order (odd) microstrip mode coupled electromagnetically through a slotline on the opposite side of the substrate. Theoretic results based on rigorous Green's impedance integral equation method show that the new microstrip-slotline-coupled leaky-wave antenna has a broadband tuning range via structure parameters and is insensitive to the microstrip line width variation. Measured relative power absorbed (RPA) results indicate that the useful frequency bandwidth agrees with that predicted by rigorous field theory. The measured antenna radiation patterns also agree very well with the approximate theoretic computations. The theory and experiments show that the proposed leaky-wave antenna can interface to feeding structure easily and directly. The new antenna may become a good candidate for microwave and millimeter-wave integrated antenna design     

Novel Microstrip Photonic Bandgap Cell Structures

In general, a planar microstrip photonic bandgap (PBG) structure os a periodic array of holes etched in the ground plane of a microstrip line. To use a circuit with a PBG, the PBG structure cannot be fixed on a metal base and needs to be shielded. In this paper, two kinds of novel microstrip PBG unit cells with special patterns etched in the strip line, which can be used as the conventional microstrip circuits, are proposed and analyzed in detail. The results show that the transmission line theory is valid for the theoretic analysis of PBG circuits.     

Hybrid-mode analysis of multilayered and multiconductortransmission lines

Hybrid-mode propagation properties of multilayered and multiconductor transmission lines are studied by using an efficient vector finite element method (FEM) with high-order hybrid edge/nodal triangular elements, which can give frequency-dependent propagation constants directly. Characteristic impedances are also calculated from the FEM field solutions employing a reciprocity-related definition and taking the modal orthogonality into account. The numerical results of a coupled microstrip line are compared with those of the boundary integral equation technique, and good agreement is obtained. Also, a dual-plane triple microstrip line is analyzed. The approach is found to be very general and able to simultaneously handle different thicknesses and widths of strip conductors. The flexibility of the approach is also shown by including anisotropy in the dielectric substrates of such lines     

Analysis of an aperture coupled microstrip antenna

A microstrip patch antenna that is coupled to a microstripline by an aperture in the intervening ground plane is analyzed. Coupled integral equations are formulated by using the Green's functions for grounded dielectric slabs so that the analysis includes all coupling effects and the radiation and surface wave effects of both substrates. A Galerkin moment method solution of the coupled integral equations agrees quite well with measured data. Design data are contained in parameter studies, many of which are verified by experimental results.     

Integral equation analysis of artificial media

This paper presents an integral equation and method of moments (MM) solution to determine the effective permittivity and permeability of an artificial medium. The artificial medium is modeled as a triple infinite periodic array of identical scattering elements. A plane wave of unknown phase constant is assumed to propagate in the periodic medium in a given direction, and the periodic moment method (PMM) is used to set up a matrix equation for the currents on the center element of the periodic array. By setting the determinant of the PMM impedance matrix to zero, one can determine the phase constant of the plane wave, and then the effective permittivity and permeability of the artificial medium     

Slow wave propagation using interconnections for IC technologies

A microstrip slow wave transmission line, based on a periodic structure made with the two metallic levels used in ICs, is described. Using on-wafer measurements, an effective permittivity as high as 20 in a wide microwave frequency range is reported. The transmission line has also been measured to obtain the characteristic impedance and the losses. Using the basic periodic structure theory the propagation constant of this media has been computed and good agreement has been obtained with that of the measurement. This slow wave structure is very promising for use in MMIC because of its very compact design.<>     

新型微带缝隙天线的阻抗特性研究

在互易原理的基础上,用矩量法在谱域内求解一种新型（带盖板的）微带缝天线的输入阻抗,并与通常意义上的微带缝隙天线进行比较,开拓了微带缝隙天线的应用范围。     

Analyse de la transition microruban-microfente au moyen d’équations intégrales

An integral equation technique solved by the moment method associated with the simple multiport model is used to analyse the electromagnetic coupling in a slotline-microstrip transition. Results obtained on the transition as well as on a slotline dipole excited by a microstrip line are compared with those obtained experimentally.     

Input impedance and radiation pattern of cylindrical-rectangularand wraparound microstrip antennas

The radiation from a cylindrical microstrip antenna excited by a probe is analyzed. Both the cylindrical-rectangular and the wraparound elements are discussed. The current distribution on the patch is rigorously formulated using a cylindrically stratified medium approach. A set of vector integral equations is derived which governs the current distribution on the patch. The set of equations is then solved using a moment method. The input impedance and the radiation pattern are derived both exactly and in the small substrate thickness limit     

Full-wave analysis of radiated emission from arbitrarily shapedprinted circuit traces

A mixed (scalar and vector) potential surface integral equation formulation, developed for microstrip antennas, is employed in conjunction with the method of moments to predict the radiated emission from arbitrarily shaped printed circuit traces. Computed currents and radiated fields for a typical trace configuration in the form of a rectangular loop loaded by low- or high-impedance lumped loads indicate good agreement with transmission line theory and/or elementary loop antenna analysis, when the trace size is electrically small. Computed results are presented to highlight the radiation and coupling due to common-mode currents