Application of the Shifted Frequency Internal Equivalence to Two Dimensional Lossy Objects

A Köksal,B Aydemir

doi:10.7716/aem.v8i2.997

Abstract

Performance of a new method, Shifted Frequency Internal Equivalence (SFIE) is studied in the analysis of scattering from two dimensional lossy objects. This method finds the solution of a wideband scattering problem faster than classical approaches.By introducing conductivity, loss shows itself as imaginary electrical permittivity. Changing conductivity also changes the distribution of electromagnetic waves and modifies RCS plots. In this study homogeneous and inhomogeneous conductive media are investigated to widen the usage of SFIE method. By increasing conductivity skin effect phenomenon is observed, electrical dimensions are decreased and RCS plots are flattened as expected.Numerical results obtained by SFIE are compared to the ones obtained by Method of Moments and the differences are shown.

Highlights

The demands of numerical electromagnetic analysis of scattering objects increase in proportion to the developments in radar, antennas and microwave technologies etc
Since integral calculations are done for every single frequency, several methods are introduced to speed up this process such as; interpolation, asymptotic approach and characteristic basis function method [3]-[5]. All these methods rely on approximating the new MoM matrix and are different from our approach where the method is exact at the new frequency
This work investigates in detail the application of Shifted Frequency Internal Equivalence (SFIE) method to two dimensional lossy objects

Summary

Introduction

The demands of numerical electromagnetic analysis of scattering objects increase in proportion to the developments in radar, antennas and microwave technologies etc. Since integral calculations are done for every single frequency, several methods are introduced to speed up this process such as; interpolation, asymptotic approach and characteristic basis function method [3]-[5]. All these methods rely on approximating the new MoM matrix and are different from our approach where the method is exact at the new frequency. MoM formulation for volume integral equations is chosen to be the reference method and the numerical results given by SFIE and MoM are compared. In addition to comparison of RCS results, z component of the internal electric field, EZ ,is compared for various conductivities, frequencies and sizes

Theory

Algorithm Comparison

Effect of conductivity on a scatterer with constant electrical dimensions

Effect of conductivity on a scatterer with constant real dimensions

Conclusions