A Circuit Approach for the Electromagnetic Analysis of Inhomogeneous Cylindrical Structures

Abstract

Abstract-An equivalent circuit, made of the chain connection of a number of T-type two-port networks, is proposed for the very accurate representation of the frequency-domain behavior of radially inhomogeneous solitary cylindrical structures, the individual two-port networks being made of frequency-independent R, L and C lumped elements. The accuracy of the model is dictated by the number of two-port networks, a number that increases with the frequency. The equivalent circuit approach is validated with the help of an application example concerning a special type of inhomogeneous tubular structures where exact closed-form field solutions do exist.

Computation of Electric and Magnetic Field Distribution Inside a Multilayer Cylindrical Conductor

“…This is a direct consequence of choosing the right general solution for electric and magnetic fields of Eqs. (8)- (9), which ensures numerical stability in all cases. The key quantity that ensures numerical stability in the coefficients of the linear system of equations is the quantityν i , described by (20) which for high frequencies tends to zero.…”

“…Therefore, introducing equations for electric and magnetic fields of Eqs. (8)- (9) into Eqs. (10)-(14), the following system of equations is obtained:…”

“…In the available literature, most authors analyze homogeneous single-layer conductors [2][3][4][5][6], in some cases two-layer conductors [7,8], and some consider multilayer conductors [9][10][11]. In the case of cylindrical multilayer structures, the authors in [9][10][11] utilize a cascade of two-port networks to model a multilayer structure. The problem that occurs with this approach lies in the inherent numerical instability present in the transfer matrix of the system, where some elements of the matrix tend to infinity for high frequencies even for extra thin layers.…”

“…In this paper, a different approach to model multilayer structures will be presented, which is both numerically robust and highly accurate. In addition, the proposed algorithm features a smaller number of unknowns than those in [9][10][11]. In the numerical algorithm proposed in this paper, a multilayer cylindrical structure consisting of an arbitrary number of layers is considered.…”

Analysis of Electromagnetic Cylindrical Wave Interaction With Inhomogeneous Planar Media

“…Inhomogeneous media are described by the constitutive parameters varying with spatial variables and are efficiently used in various microwave devices [1][2][3]. Exact solution of the wave equation in inhomogeneous media is known for only a few particular profiles; and due to this, the scattering from inhomogeneous media has been intensively investigated and several approaches for analyzing such problems have been presented [4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”