A novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly accurate results whereas the computational time is reduced by up to one order of the magnitude.
A combination of the body-of-revolution and finite element methods is adopted for full-wave analysis of waveguides and waveguide discontinuities involving angular field variation. Such an approach is highly efficient and much more flexible than analytical techniques. The method is performed in two different cases: utilizing a generalized impedance matrix to determine the scattering parameters of a single waveguide section and utilizing periodic boundary conditions without sources. In order to confirm the validity and efficiency of both approaches, a few examples of axially symmetrical structures have been analyzed. The obtained results are compared to those obtained from commercial software and available in the literature.
A hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of the scatterer. Moreover, once the impedance matrix is calculated, any rotation or shifting of the post can be performed without the need for structure recalculation. All the obtained results have been verified by comparison with simulations performed using the hybrid finite-difference-modematching method and commercial software.
A problem of electromagnetic wave scattering from cylindrical posts of arbitrary cross section located in waveguide junction is presented. The method of analysis is based on the direct ﬁeld matching technique. Multimode scattering matrices of every section of waveguide junction are calculated and cascading procedure is utilized to investigate the whole structure. The results are veriﬁed by comparing them with those obtained from the mode matching method analysis as well as commercial software calculations.
A problem of electromagnetic wave scattering from multilayered frequency selective surfaces is presented. Each surface is composed of periodically arranged cylindrical posts of arbitrary convex cross-section. The method of analysis is based on the direct ﬁeld matching technique for a single cell, and the transmission matrix method with the lattice sums technique for periodic arrangement of scatterers.
A problem of electromagnetic wave scattering from ferrite post is presented. The post is assumed to be located in closed areas as waveguide junction, or in open area illuminated by a plane wave. The object is of arbitrary convex cross section and the method of analysis is semi-analytical, based on the direct ﬁeld matching technique.
A hybrid technique was employed for the analysis of the resonance frequency of thin planar and cylindrical microstrip structures with the patches of arbitrary geometry. The proposed technique utilizes a combination of Galerkin’s moment method and a finite-element method (FEM). In this approach, an FEM is adopted to calculate the patch surface current densities, and a method of moments is utilized to calculate the resonance frequencies of the microstrip structure. The technique allows the analysis of different shaped patches. To verify the validity of the approach, the results were compared with those obtained from commercial software and actual measurements of manufactured prototypes.
An interactive computer application visualizing the basic phenomena in RF and microwave devices is presented. Such kind of educational package can be a very helpful tool for the students as well as for the teachers (of electronics and related ﬁelds). This paper is focused on three exemplary problems only and involves: movement of electric charge, ﬁltering of electromagnetic waves and interference phenomena in antenna arrays. The main part of the application (engine) is based on standard techniques. The package is designed in a game form which should increase the attractiveness of the application and improves learning outcomes.
A simple solution to propagation problem in open waveguides and dielectric fibers of arbitrary convex cross section is presented. The idea of the analysis is based on the direct field matching technique involving the usage of the field projection at the boundary on a fixed set of orthogonal basis functions. A complex root tracing algorithm is utilized to find the propagation coefficients of the investigated guides. Different convex shapes of the guides are analyzed, and the obtained results are compared with the alternative solutions to verify the validity of the proposed method.