Numerical implementation of the mixed potential integral equation for planar structures with ferrite layers arbitrarily magnetized

This work presents a new implementation of the mixed potential integral equation (MPIE) for planar structures that can include ferrite layers arbitrarily magnetized. The implementation of the MPIE here reported is carried out in the space domain. Thus it will combine the well-known numerical advantages of working with potentials as well as the flexibility for analyzing nonrectangular shape conductors with the additional ability of including anisotropic layers of arbitrarily magnetized ferrites. In this way, our approach widens the scope of the space domain MPIE and sets this method as a very efficient and versatile numerical tool to deal with a wide class of planar microwave circuits and antennas.Ministerio de Educación y Ciencia TEC2004-0321

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

A suitable integral equation for the quasi-TEM analysis of hybrid strip/slot-like structures

This paper reports on a suitable formulation of the spectraldomain/integral-equation method for the quasi-TEM analysis of hybrid strip/slot-like planar lines. The free surface charge distribution is used as an unknown on the strip-like interface, whereas the electric field is used on the slot-like region. This formulation allows us to reduce the number of basis functions and makes possible a unified treatment of the problem. A single type of basis functions is used, leading to a quasi-analytical evaluation of the Galerkin matrix entries. The performance of the method is illustrated with a practical example structure useful for coupler design

Comments on "Internal impedance of conductors of rectangular cross section"

The alternate current (ac) internal impedance of rectangular cross-sectional conductors used as transmission lines and interconnects in microwave and digital printed circuits were analyzed. The difference between the real and imaginary parts of internal impedance to the existence of right-angle corners in the rectangular cross-sectional geometrics were studied. The corners are responsible for the nonconstant distribution of the currents along the periphery of the conductors. The consideration of incremental inductance was correlated to nonperfect nature of the conductors rather than internal inductance

Capacitance and Inductance Matrices for Multistrip Structures in Multilayered Anisotropic Dielectrics

In this paper we present a unified variational approach to determine the capacitance and inductance matrices of generalized multistrip systems embedded in a multilayered iso/anisotropic dielectric lossless medium. The analysis is carried out in the spectral domain to take advantage of previously obtained recurrence relations which calculate the Green's function in the spectral domain. The method leads to a low-order system of linear equations, which is shown explicitly. Examples and comparison with previously published results have been included

Quasi-Analytical Static Solution of the Boxed Microstrip Line Embedded in a Layered Medium

In this paper, a quasi-analytical method is presented to carry out the quasi-TEM study of a microstrip line embedded in a general layered substrate with rectangular enclosure. Electric walls, magnetic walls and periodic boundary conditions are considered. The analysis is based on the spectral domain formulation and the use of a proper expansion of the free charge distribution (Chebyshev polynomials with edge condition). Two different approaches are proposed to speed up the evaluation of the spectral series in such a way that only a few spectral terms must be retained in the numerical computations of the mentioned series. The propagation parameters and the charge distribution are obtained with extreme accuracy in fractions of one second on a personal computer

Physically-insightful equivalent circuit models for electromagnetic periodic structures

In this presentation it will be discussed how to obtain analytical or quasi-analytical equivalent circuits to deal with periodic structures such as frequency selective surfaces and/or metasurfaces. Both the topology and the values of the involved elements of these circuits are obtained from a basic rationale to solve the corresponding integral equation. This procedure, besides providing a very efficient analysis/design tool, allows for a good physical insight into the operating mechanisms of the structure in contrast with the almost blind numerical scheme of commercial simulators.Ministerio de Economía y Competitividad TEC2013-41913-PJunta de Andalucía P12-TIC-143

Some advances in the circuit modeling of extraordinary optical transmission

The phenomenon of extraordinary optical transmission (EOT) through electrically small holes perforated on opaque metal screens has been a hot topic in the optics community for more than one decade. This experimentally observed frequency-selective enhanced transmission of electromagnetic power through holes, for which classical Bethe's theory predicts very poor transmission, later attracted the attention of engineers working on microwave engineering or applied electromagnetics. Extraordinary transmission was first linked to the plasma-like behavior of metals at optical frequencies. However, the primary role played by the periodicity of the distribution of holes was soon made evident, in such a way that extraordinary transmission was disconnected from the particular behavior of metals at optical frequencies. Indeed, the same phenomenon has been observed in the microwave and millimeter wave regime, for instance. Nowadays, the most commonly accepted theory explains EOT in terms of the interaction of the impinging plane wave with the surface plasmon-polariton-Bloch waves (SPP-Bloch) supported by the periodically perforated plate. The authors of this paper have recently proposed an alternative model whose details will be briefly summarized here. A parametric study of the predictions of the model and some new potential extensions will be reported to provide additional insight.Ministerio de Ciencia e Innovación TEC2007-65376, CSD2008-0006

On the Computation of the Dispersion Diagram of Symmetric One-Dimensionally Periodic Structures

A critical discussion on the computation of the dispersion diagram of electromagnetic guiding/radiating structures with one-dimensional periodicity using general-purpose electromagnetic simulation software is presented in thiswork. In thesemethods, full-wave simulations of finite sections of the periodic structure are combined with appropriate simplifying network models. In particular, we analyze the advantages and limitations of two different combined methods, with emphasis on the determination of their range of validity. Our discussion is complemented with several selected numerical examples in order to show the most relevant aspects that a potential user of these methods should be aware of. Special attention is paid to the relevant role played by the high-order coupling between adjacent unit cells and between the two halves of unit cells exhibiting reflection, inversion, and glide symmetries.Ministerio de Ciencia, Innovación y Universidades TEC2017-84724-

Circuit model for a periodic array of slits sandwiched between two dielectric slabs

This paper proposes an equivalent circuit model that uses lumped elements and transmission lines to explain the transmission of electromagnetic waves through a conducting screen periodically perforated with slits and sandwiched between two different dielectric slabs. The present model relies on the impedance-matching point of view, previously introduced by some of the authors, rather than on the surface plasmon polariton concept. Thus, the model constitutes a simple and insightful framework that easily leads to accurate qualitative and quantitative predictions about the nature of the transmission spectrum of such structures.Ministerio de Ciencia e Innovación TEC2007-65376, CSD2008-00066Junta de Andalucía TIC-459