Determination of Dependence of Attenuation on Material Thickness of Low-Density Polyethylene at Microwave Frequency

Abstract

The attenuation of the electromagnetic wave signal due to power absorption by materials contributes to assessing the suitability of materials for use in microwave applications. One of the factors affecting power attenuation is material thickness. Therefore, this study investigates the effect of material thickness on the S-parameters and attenuation properties of low-density polyethylene (LDPE) at the X-band frequency range (8GHz-12GHz) to optimise the experimental design and reduce the cost associated with material preparation. The Waveguide measurement technique along with the finite element method (FEM) was implemented in COMSOL Multiphysics software for the study and analysis. The length of the waveguide was 200mm while the length and width of the waveguide ports were 22.28mm and 0.1143mm, respectively. The thickness of the LDPE was varied from 6mm-14mm with 2mm increment. Variation of S11 and S21 as functions of material thickness were determined and analysed. S11 decreased from 0.51 to 0.32 and S21 increased from 0.85 to 0.93 at 6mm and 14mm of the material thickness, respectively. The attenuation of the LDPE due to power loss decreased from 1.37 to 0.31 at 6mm and 14mm, respectively. It is determined from the results obtained that attenuation decreases as the thickness of the material increases, thereby reducing power loss due to absorption by the material.