Study of the influence of Carbonyl iron particulate size as an electromagnetic radiation absorbing material in 12.4 to 18 GHz (Ku) Band

Abstract

This paper presents the influence of different sizes of carbonyl iron particles on the reflectivity measurements of Radar Absorbing Material (RAM). The electromagnetic characterization was performed with a vector network analyzer and a rectangular waveguide in the frequency range of 12.4 to 18GHz (Ku Band). The influence of different parameters such as thicknesses, particle sizes and concentration of carbonyl iron were evaluated. Reflectivity results showed the influence of these parameters on the performance of the RAM. The best reflectivity values (~-18 dB) were obtained for samples with 60 wt% concentration and 5 mm thickness. We provide information about significantly reflection loss improvement by simply controlling carbonyl iron particulate size. Index Termscarbonyl iron filler, Ku band, microwave absorber. I. INTRODUCTION Radar Absorbing Material (RAM) is a type of material designed to attenuate electromagnetic radiation on specific frequencies. Many researches have been made about RAM due its countless applications in electromagnetic compatibility and interference reduction. These materials can be applied on communication systems, modern electronic devices, anechoic chamber, military stealth technology, and so on [1]. RAMs can be produced in different forms, such as paints or thin films [2]. Usually, RAMs are composite materials made with polymer (matrix) and absorptive material (mean). In the literature, materials with dielectric and/or magnetic losses are commonly used as means. In this matter, materials like ferrite, carbonyl iron (CI), carbonaceous materials and conductive polymers has advantages over lossless materials [2],[3]. Despite their high specific mass, composites made with ferrites or CI have advantages like thin thickness and broadband frequency absorption because of iron on their compositions [4]. Carbonyl iron has a relatively low electrical conductivity, a high Curie temperature, and a high saturation magnetization. These properties make CI a good candidate to be used as absorption mean, especially in the frequency range between 2-18 GHz [5]. The effectiveness of the absorptive material contributes to the reflectivity losses that are determined

Design of a wideband and tunable radar absorber

“…The development of radar absorption materials has advanced rapidly along with the advancements in radar detecting capacity. Researchers have worked hard to increase the absorbing property and absorbing bandwidth, changing the morphology and size of the absorbent [1][2][3], combining different materials [4][5][6][7], optimizing the distribution of the absorbent in the matrix [8], using core-shell structure [9], sandwich structure [10], metamaterials [11,12], FSS(frequency selective surface) [13,14], and dielectric resonance unit [15][16][17], among other things. The aforementioned techniques, however, are passive radar stealth, once established, their absorption performance will not change in response to changes in the surrounding electromagnetic field.…”