According to various embodiments, an electronic device may comprise: a housing; an antenna structure disposed in an inner space of the housing, the antenna structure including a substrate having a first surface and a second surface oriented toward a direction opposite to the first surface, and at least one first antenna element disposed in a space between the first surface and the second surface and having a beam pattern formed toward a conductive part; an electric wave absorbing member disposed between the conductive part and the at least one first antenna element so as to be disposed in a path in which the beam pattern is formed; and a first wireless communication circuit disposed in the inner space of the housing and configured to transmit or receive a wireless signal of a first frequency band through the at least one first antenna element.

An electromagnetic wave absorbing thermally conductive composition contains a matrix resin component, metal soft magnetic particles, and thermally conductive particles. The metal soft magnetic particles are carbonyl iron particles and are present in an amount of 30% by volume or more when the electromagnetic wave absorbing thermally conductive composition is a population parameter. A value of an imaginary part (μ″) of relative permeability of the electromagnetic wave absorbing thermally conductive composition is 0.9 or more in at least some bands in a frequency range of 18 to 26.5 GHz. The electromagnetic wave absorbing thermally conductive composition in the form of a sheet has a thermal conductivity of 2.0 W/m.Math.K or more in the thickness direction. A sheet of the present invention incudes the above composition in the form of a sheet. Thus, the present invention provides the electromagnetic wave absorbing thermally conductive composition and its sheet that can increase the value of the imaginary part (μ″) of relative permeability in a frequency band of 18 to 26.5 GHz, efficiently absorb electromagnetic wave noise in this frequency band, and also have a high thermal conductivity.

An air duct formed from an electromagnetic wave absorber in the form of a sheet is disclosed. The sheet can be bent into a duct or scored, and folded at the score lines to bring the ends of the sheet into proximity. The ends can then be joined by adhesive, welding, or mechanical fasters. The air ducts disclosed herein provide dual functions of providing ventilation for electronic components in an electronic module, while at the same time, reducing electromagnetic interference (EMI). One or more air ducts, of the same or different dimensions, shapes, volumes can be combined with electronic modules, such as a server, to provide both ventilation and EMI suppression to various components within the electronic module.

An air duct formed from an electromagnetic wave absorber in the form of a sheet is disclosed. The sheet can be bent into a duct or scored, and folded at the score lines to bring the ends of the sheet into proximity. The ends can then be joined by adhesive, welding, or mechanical fasters. The air ducts disclosed herein provide dual functions of providing ventilation for electronic components in an electronic module, while at the same time, reducing electromagnetic interference (EMI). One or more air ducts, of the same or different dimensions, shapes, volumes can be combined with electronic modules, such as a server, to provide both ventilation and EMI suppression to various components within the electronic module.

A method for producing a layer of a device for electromagnetic radiation absorption, includes: providing a ply of powder material in the layer to be produced of the device; providing a predefined concentration distribution of particles for electromagnetic radiation absorption in the layer; providing a first binder and a second binder for the powder materials, wherein the first binder includes particles for the absorption of electromagnetic radiation, wherein the second binder includes a lower concentration of identical and/or different particles than the first binder; determining a mixing ratio between the first binder and the second binder for every position in the layer; selecting a position of the layer; mixing the first and second binder according to the mixing ratio for the selected position; wetting the powder material at the selected position using the mixed first and second binders; and repeating selecting, mixing, and wetting to produce the layer.

An antenna system and method for fabricating an antenna are provided. The antenna system includes a substrate and an antenna. The antenna includes a conductive particle based material applied onto the substrate. The conductive particle based material includes conductive particles and a binder. When the conductive particle based material is applied to the substrate, the conductive particles are dispersed in the binder so that at least a majority of the conductive particles are adjacent to, but do not touch, one another.

Embodiments disclosed herein relate to using cobalt (Co) to fine tune the magnetic properties, such as permeability and magnetic loss, of nickel-zinc ferrites to improve the material performance in electronic applications. The method comprises replacing nickel (Ni) with sufficient Co.sup.+2 such that the relaxation peak associated with the Co.sup.+2 substitution and the relaxation peak associated with the nickel to zinc (Ni/Zn) ratio are into near coincidence. When the relaxation peaks overlap, the material permeability can be substantially maximized and magnetic loss substantially minimized. The resulting materials are useful and provide superior performance particularly for devices operating at the 13.56 MHz ISM band.

Disclosed herein are embodiments of modified z-type hexagonal ferrite materials having improved properties that are advantageous for radiofrequency applications, in particular high frequency ranges for antennas and other devices. Atomic substitution of strontium, aluminum, potassium, and trivalent ions can be used to replace certain atoms in the ferrite crystal structure to improve loss factor at high frequencies.

One subject of the present invention is an electromagnetic-wave-absorbing composite material comprising a carrier matrix (11) and an electromagnetic-wave-absorbing filler (12). According to the invention, the carrier matrix (11) is a cork matrix, which is formed of particles the equivalent diameter D.sub.el of which is comprised between 10 μm and 5 mm, and the composite material (1) has a real permittivity higher than 1.2 and a dielectric loss tangent tan δ higher than 0.1. Another subject of the present invention is a method for producing such a material, and the use of this material as an absorber, in particular in an anechoic chamber, or as a radar absorber in stealth devices, or even to improve the electromagnetic compatibility of electronic devices.

A radio wave absorbing member 1a includes a radio wave absorber 10 and a support 20 having a sheet shape. The radio wave absorber 10 includes a resistive layer 12, a reflective layer 14, and a dielectric layer 13. The reflective layer 14 reflects a radio wave. The dielectric layer 13 is disposed between the resistive layer 12 and the reflective layer 14 in the thickness direction of the reflective layer 14. The support 20 supports the radio wave absorber 10. The support 20 includes a matrix resin 20m and a flame retardant 20p.