M. Horno

A general algorithm for computing the bidimensional spectral Green's dyad in multilayered complex bianisotropic media: the equivalent boundary method

A systematic method to obtain the bidimensional spectral dyadic Greens function of stratified planar structures with arbitrary complex bianisotropic layers is developed. The method is based on the uniqueness and equivalence electromagnetic theorems. A first-order partial differential formulation for the electromagnetic field inside each layer is used. An explicit algorithm makes it possible to go from the single-layer formulas to the general multilayer matrix formulation. The perturbative nature of the method provides good numerical efficiency and straightforward determination of asymptotic behavior. >

Quasi-TEM analysis of multilayered, multiconductor coplanar structures with dielectric and magnetic anisotropy including substrate losses

A quasi-TEM (transverse electromagnetic) analysis of multiconductor planar lines embedded in a layered structure involving lossy iso/anisotropic electric and/or magnetic materials is achieved. Conditions under which a quasi-TEM assumption is valid are theoretically determined. An efficient spectral-domain analysis is used to determine the complex capacitance and inductance matrices characterizing the transmission system. computation of the inductance matrix is reduced to the computation of an equivalent capacitance matrix when media characterized for a fully general permeability tensor are present. It is also shown that most actual monolithic microwave integrated circuit (MMIC) microstrip-type structures (where semiconductor substrates are present) and possible future applications including lossy magnetic materials can be analyzed by using the simple quasi-TEM model. The validity of the results has been verified by comparison with full-wave theoretical and experimental data on microstrip lines on magnetic substrates and slow-wave structures. >

Full-wave analysis of circular microstrip resonators in multilayered media containing uniaxial anisotropic dielectrics, magnetized ferrites, and chiral materials

In this paper, Galerkins method in the Hankel transform domain is applied to the determination of the resonant frequencies, quality factors, and radiation patterns of circular microstrip patch resonators. The metallic patches are assumed to be embedded in a multilayered substrate, which may contain uniaxial anisotropic dielectrics, magnetized ferrites, and/or chiral materials. The numerical results obtained show that important errors can be made in the computation of the resonant frequencies of the resonators when substrate dielectric anisotropy, substrate magnetic anisotropy and/or substrate chirality are ignored. Also, it is shown that the resonant frequencies of circular microstrip resonators on magnetized ferrites can be tuned over a wide frequency range by varying the applied bias magnetic field. Finally, the computed results show that the resonance and radiation properties of a circular microstrip patch on a chiral material is very similar to those of a circular patch of the same size printed on a nonchiral material of lower permittivity.

On the fast approximation of Green's functions in MPIE formulations for planar layered media

The numerical implementation of the complex image approach for the Greens function of a mixed-potential integral-equation formulation is examined and is found to be limited to low values of /spl kappa//sub o//spl rho/ (in this context /spl kappa//sub 0//spl rho/ = 2/spl pi//spl rho///spl lambda//sub 0/, where /spl rho/ is the distance between the source and the field points of the Greens function and /spl lambda//sub 0/ is the free space wavelength). This is a clear limitation for problems of large dimension or high frequency where this limit is easily exceeded. This paper examines the various strategies and proposes a hybrid method whereby most of the above problems can be avoided. An efficient integral method that is valid for large /spl kappa//sub 0//spl rho/ is combined with the complex image method in order to take advantage of the relative merits of both schemes. It is found that a wide overlapping region exists between the two techniques allowing a very efficient and consistent approach for accurately calculating the Greens functions. In this paper, the method developed for the computation of the Greens function is used for planar structures containing both lossless and lossy media.

Generalized spectral analysis of planar lines on layered media including uniaxial and biaxial dielectric substrates

The spectral-domain analysis is generalized to compute the dispersive properties of a wide variety of planar and quasiplanar transmission lines (microstrips and finlines) printed on a stratified dielectric medium. Uniaxial and biaxial dielectric anisotropy can be easily manipulated due to the definition of a transverse propagation matrix characterizing each dielectric layer. The whole boundary value problem is reduced to two simpler problems involving only one or two dielectrics, and the spectral dyadic Greens function is derived by a recurrence algorithm. The dispersion equation is derived by using the Ritz-Galerkin method. The numerical convergence is substantially improved taking into account the asymptotic behavior of the series. A number of illustrative examples are included to emphasize the power of the method. >

Quick quasi-TEM analysis of multiconductor transmission lines with rectangular cross section

This paper presents an efficient and accurate procedure for computing the quasi-static matrix parameters ([C], [L], [G], and [R]) of rectangular-shaped conductors embedded in a multilayered dielectric medium over an infinite ground plane. An additional top ground plane can also be considered., The problem is formulated in terms of the space-domain integral equation for the free-charge distribution on the slab conductor surfaces. The spatial Greens function is computed from its spectral counterpart using system identification techniques [Pronys method or matrix pencil method (MPM)]. The integral equation is solved by means of a Galerkin scheme employing entire domain basis functions. This results in a small matrix size. In addition, the quasi-analytical evaluation of the entries of the Galerkin matrix leads to a very efficient and accurate computer code. A detailed study on the convergence and accuracy of the method has been included.

Determination of Green's Function Matrix for Multiconductor and Anisotropic Multidielectric Planar Transmission Lines: A Variational Approach

In this paper, a set of simple recurrence formulas to evaluate the Greens function matrix for a generic multiconductor and multidielectric planar transmission system with arbitrary rectangular boundary conditions is obtained. Combining these formulas with the variational technique in the spectral domain, two useful algorithms to calculate the capacitance matrix of a very wide range of practical configurations are proposed. Upper and lower bounds on mode capacitances are obtained by using both algorithms. A number of practical structures have been analyzed and their most interesting features discussed, The method is very versatile and can handle a large class of MIC configurations, no matter how complex the planar structure.

Fast full-wave analysis of multistrip transmission lines based on MPIE and complex image theory

The mixed-potential electric-field integral equation is used in conjunction with the Galerkins method and complex image theory for analyzing a transmission line with multiple strips embedded in different layers of a multilayered uniaxially anisotropic dielectric substrate. The two-dimensional Greens functions for the scalar and vector potentials are analytically obtained in the space domain due to the approximation of its spectral-domain version with complex images, thus avoiding lengthy numerical evaluations. Double integrals involved in the computation of Galerkins matrix entries are quasi-analytically carried out for the chosen basis functions, which are well suited to the problem.

An efficient numerical spectral domain method to analyze a large class 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 Greens function by the equivalent boundary method (EBM), a suitable third order extraction technique of the asymptotic behavior of the Greens 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. >

Spectral and variational analysis of generalized cylindrical and elliptical strip and microstrip lines

The variational technique in the spectral domain (VTSD) is shown to be an efficient method for computing the quasi-TEM parameters of arbitrary multiconductor and multidielectric cylindrical or elliptical strip configurations. Simple conformal mappings reduce the cylindrical or elliptical geometries to an equivalent rectangular one with periodic boundary conditions. The analysis of this equivalent structure is achieved by taking advantage of previous work on boxed planar structures. The numerical convergence of the programs is greatly accelerated, incorporating the asymptotic behavior of the series appearing in the analysis in such a way that efficient programs have been written. It is pointed out that excessively simple approximations to the surface charge distribution yield meaningful numerical errors, mainly when strong coupling or wide strips are involved. As an application example, the behavior of the characteristic parameters of asymmetric coupled structures on multilayer substrates is shown. >