Synthesis of an Electromagnetic Wave Absorber for High-Speed Wireless Communication

Abstract

Millimeter waves (30-300 GHz) are starting to be used in next generation high-speed wireless communications. To avoid electromagnetic interference in this wireless communication, finding a suitable electromagnetic wave absorber in the millimeter wave range is an urgent matter. In this work, we prepared a high-performance millimeter wave absorber composed of a series of aluminum-substituted epsilon-iron oxide, epsilon-Al(x)Fe(2-x)O(3), nanomagnets (0 < or = x < or = 0.40) with a particle size between 25 and 50 nm. The materials in this series have an orthorhombic crystal structure in the Pna2(1) space group, which has four nonequivalent Fe sites and Al ion that predominantly occupies the tetrahedral [FeO(4)] site. The field-cooled magnetization curves showed that the T(C) values were 448, 480, and 500 K for x = 0.40, 0.21, and 0, respectively. The magnetization versus external magnetic field showed that the coercive field H(c) values at 300 K were 10.2, 14.9, and 22.5 kOe for x = 0.40, 0.21, and 0, respectively. The millimeter wave absorption properties were measured at room temperature by terahertz time domain spectroscopy. The frequencies of the absorption peaks for x = 0.40, 0.30, 0.21, 0.09, 0.06, and 0 were observed at 112, 125, 145, 162, 172, and 182 GHz, respectively. These absorptions are due to the natural resonance achieved by the large magnetic anisotropies in this series. Such frequencies are the highest ones for magnetic materials. Because aluminum is the third most abundant atom, aluminum-substituted epsilon-iron oxide is very economical, and thus these materials are advantageous for industrial applications.

Metamaterial Electromagnetic Wave Absorbers

“…Absorbers that serve this purpose have been made, for example, from nanomagnets and were shown to suffi ciently absorb millimeter waves. [ 15 ] …”

High-frequency Millimeter Wave Absorber Composed of a New Series of Iron Oxide Nanomagnets

“…20,25 The magnetic permeability of such millimeter wave absorbers is important to determine the attenuation and reflection properties, for the purpose of designing a millimeter wave absorber painted on a wall. Here we describe the reflectance and transmittance data of a series of ε-Ga x Fe 2-x O 3 (x= 0.51, 0.56, 0.61) in the region of 60 GHz band (V-band) and the evaluation of the magnetic permeability.…”

Hydrothermal Synthesis of Three-dimensional Butterfly-like Ni Architectures as Microwave Absorbers

“…The development of electromagnetic (EM) wave absorbers has been a recent focus towards solving the serious EM pollution arising from the fast-growing generation and applications of electronic devices [1][2][3][4][5] . Among various potential candidates for EM wave absorbers, the one in the form of magnetic nanoparticles core/ dielectric shell-structured nanocapsules, such as Ni/ZnO, FeNi 3 /SiO 2 , Ni/PANI, Ni/C, and Ni/Ni 2 O 3 nanocapsules, has been of particular interest in recent years owing to its tailorable properties in conjunction with smaller sizes and weights [6][7][8][9][10] .…”