Multilayer Structure Technique for Improving Determination of Electromagnetic Properties of Radar Absorbers Based on Two-Layer Method and Flanged Rectangular Waveguide Probe

Abdulkadhim Ameen Hassan,Janan Hammed Saadie

doi:10.11591/ijeei.v8i4.1444

Abdulkadhim Ameen Hassan, Janan Hammed Saadie

Open Access

https://doi.org/10.11591/ijeei.v8i4.1444

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Abstract

This paper presents further development of utilization of two-layer method to perform nondestructive electromagnetic properties determination of planar radar absorbers using flanged open-ended rectangular waveguide probe. A multilayer structure of three layers was proposed to improve the measured results of these parameters obtained using two-layer method. These layers were arranged such that the test material is sandwiched between two known low loss materials to provide the needed two independent reflection coefficients necessary to extract them at different conditions of testing. The proposed structure was aimed to decrease the effect of direct backing of test material by metal plate, which influences measurement accuracy if two-layer method is used. The structure permits a suitable electric field interrogation in test material and decreases the influences of both radial and surface waves. FDTD method was adapted for modeling the problem geometry to calculate the reflection coefficients since a probe with finite flange size is used. Measurements were carried out using the proposed technique to determine complex permittivity and complex permeability of several radar absorbers over X-band applications of microwaves. In comparison with both single-layer and two-layer methods results, the measured results of these parameters agreed well with the published data. by companies and literatures.

Highlights

In many applications of microwaves, evaluation of materials electromagnetic properties accurately has significant importance over the recent decades
The first part is hardware-oriented and consisting of X-band rectangular waveguide probe placed on the top of the layered structure and with automatic network analyzer (ANA) used for reflection coefficient measurement
A series of experiments were carried out using rectangular waveguide probe with flange dimension of 50 mm to extract both complex permittivity εr(f)=(ε'-jε") =ε'(1-jtanδε) and complex permeability μr(f) = μ'jμ")= μ'(1-jtanδμ) of several radar absorbers

Summary

Introduction

In many applications of microwaves, evaluation of materials electromagnetic properties accurately has significant importance over the recent decades. Based on electromagnetic field interaction with materials, researchers have spent considerable efforts, for many years, in developing measurement techniques to measure both complex permittivity (εr) and complex permeability (μr) conveniently, accurately and quickly [5,6,7,8]. Each one of these techniques is suitable for some specific applications and has some distinct advantages and drawbacks. The reflection property of the probe (Γ) is sensitive to more than one variable, which allows to measure different parameters of test material such as electromagnetic parameters (εr, μr) and its thickness as well [9,10,11,12,13]

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