Mirjana T. Perić

Hybrid Boundary Element Method and Quasi-TEM Analysis of Two-Dimensional Transmission Lines—Generalization

Abstract The hybrid boundary element method, based on the equivalent electrodes method and the boundary element method, is presented in this article. This method is applied on several examples for calculating the characteristic impedance of transmission lines. It should be emphasized that the combination of the equivalent electrodes method and a new variant of the boundary element method can be efficiently implemented in quasi-transverse electromagnetic analysis of transmission lines without loss of accuracy. All results for the characteristic impedance of the observed transmission lines are compared to corresponding ones obtained by the finite-element method.

Optimization procedure for high homogeneity field systems design

Two different approaches for homogeneous electrical field generation are presented in this paper. For this generation a primary cell which consists of toroidal electrodes is used. Potential distribution along the system axis is expanded into Taylor and Chebyshev series in the first approach. System dimensions are chosen by setting corresponding terms to zero value so that only linear term remains. In the second approach the synthesis of systems with axial potential linear distribution is performed. Optimization of the electrodes parameters was carried out using gradient method. A deviation of electric field intensity is used as a criterion of the level of obtained homogeneity.

Assessment of emissions from electrical equipment regarding human exposure — Approaches for application of the generic standard IEC 62311

In a lot of countries and regions there are requirements regarding electromagnetic emissions from electrical equipment. Such emissions can be looked at under two aspects: the emissions might interfere with other equipment in the vicinity causing potential malfunction (EMC aspect), or might be considered with regard to human exposure (EMF aspect). Limitation of such emissions related to the EMC aspect is part of EMC activities and is mostly due to the need to protect radio services from being interfered. Applicable limits depend on the type of equipment under concern and of the locations where equipment is intended to be operated. However, more and more such emissions are looked at also under a human exposure point of view within the frame of EMF regulations. As both aspects deal with entirely different objective targets consequently different limits, different measurement procedures and different assessment methods are to be applied. This could mean in practice that basically two kinds of measurements have to be carried out. This paper introduces an approach how to use results obtained by means of EMC measurements for the purpose of EMF assessments. As an example for an assessment the EMC data in the frequency range between 30 MHz and 230 MHz are used as part of an EMF assessment.

The choice of optimal system composed of linear conductors for electrostatic space protection

System of integral equations for the electric scalar potential (integral equations Rabins type), for the observed electrostatic model composed of linear conductors, can be formed. Since this equation cannot be solved correct analytically, a very simple and convenient accurate point matching method, with a polynomial approximation of functions of longitudinal charge density of conductors, has been used. A new numerical procedure for optimization of the system used for electrostatic protection of space is developed in this paper. The optimization of formed functional, consists of electrostatic energy density and system of linear equations witch follows from the equipotential character of the system of conductors, is used for the protection. By minimizing this functional, the system of nonlinear equation is obtained and then numerically solved. The energy density is defined in the points along the axis of the system. A few numerical examples are given.

Analysis of shielded coupled microstrip line with partial dielectric support

A shielded coupled microstrip line with partial dielectric support is analysed using the hybrid boundary element method (HBEM) and the finite difference method (FDM). The HBEM is a combination of the equivalent electrodes method (EEM) and the boundary element method (BEM). The microstrip line characteristic parameters: the effective relative permittivity and the characteristic impedance are determined. “Odd” and “even” modes are taken into account. The results are compared with corresponding ones found in the literature.

Covered coupled microstrip lines with ground planes of finite width

Hybrid boundary element method (HBEM), developed at the Faculty of Electronic Engineering of Niš, is used to determine characteristic parameters of a covered coupled microstrip lines with ground planes of finite width. This method is based on the combination of equivalent electrodes method (EEM) and boundary element method (BEM). All results for the characteristic impedance of observed microstrip line are compared with corresponding ones obtained by the finite element method. Even and odd modes are taken into account.

Quasi-TEM Analysis of Multilayered Shielded Microstrip Lines Using Hybrid Boundary Element Method

In this paper multilayered shielded structures have been analyzed using the hybrid boundary element method. The method is based on the equivalent electrodes method, on the point-matching method for the potential of the perfect electric conductor electrodes and for the normal component of electric field at boundary surface between any two dielectric layers. The quasi-static TEM analysis is applied. The characteristic parameters (characteristic impedance and effective relative permittivity) of shielded multilayered microstrip lines are determined. The method can be use to analyze microstrip transmission lines with arbitrary configurations, arbitrary number of conductors and dielectric layers, infinitesimally thin or finite metallization thickness and finite width of substrate. It is a simple and an accurate procedure comparing to the other numerical and semi-numerical methods. In order to verify the obtained results, they have been compared with the finite element method and results that have already been reported in the literature. A very good results agreement with available data can be noticed.

Analysis of shielded edge-compensated microstrip line using hybrid boundary element method

The characteristic parameters determination of the shielded edge-compensated microstrip (ECM) line is presented in this paper. The hybrid boundary element method is applied for those calculations. The quasi-static TEM approximation is used. Also, an influence of additional dielectric layers on the shielded ECM line characteristic impedance is analysed. The comparison of the results with those obtained by other methods is presented.

Analysis of 2D symmetrically coupled vertical microstrip lines between two infinite grounded planes using HBEM

This paper presents an application of the hybrid boundary element method, developed at our Department of Theoretical Electrical Engineering, for calculating the parameters of symmetrically coupled vertical microstrip lines placed between two infinite grounded planes. Even and odd modes are taken into account and the quasi TEM analysis is applied. A computer code has been written to obtain numerical solutions for the observed microstrip lines. The characteristic impedance and the effective dielectric permittivity will be determined and compared to corresponding ones obtained by the finite element method. All results will be given in tables and presented graphically. The basic idea of the hybrid boundary element method is that an arbitrary shaped electrode can be replaced by equivalent electrodes. Also, an arbitrary shaped boundary surface between any two dielectric layers can be replaced by discrete equivalent total charges per unit length placed in the air. The discretization technique is similar to the method of moments and is not new, but combined with a new variant of the boundary element method and the equivalent electrodes method can be applied for solving large number of very complex 2D microstrip lines with or without symmetry. The hybrid boundary element method can be also successfully applied to 3D problems solving.

Quasi TEM analysis of symmetrically coupled strip line using new hybrid boundary element method

The new hybrid boundary element method (HBEM) is based on combination between equivalent electrodes method (EEM) and boundary element method (BEM) and it is applied on coupled strip lines characteristic parameters determination. Even and odd modes are considered in the paper. All results for characteristic impedance are compared with finite element method (FEM).