Provided is an electromagnetic wave shielding and absorbing molded article which has excellent shielding properties and absorbency for electromagnetic waves having a specific frequency. The electromagnetic wave shielding and absorbing molded article includes a thermoplastic resin composition including stainless steel fibers, and the content ratio of the stainless steel fibers in the molded article is from 0.5 to 20 mass %. The electromagnetic wave shielding and absorbing molded article has a thickness from 0.5 mm to 5 mm, and a shielding property of 10 dB or greater and an absorbency of 25% or greater for electromagnetic waves having any frequency in a frequency domain from 59 GHz to 100 GHz.

A radio wave absorber including a magnetic powder and a binder, in which the magnetic powder is a powder of a hexagonal ferrite in which a ratio (σs/β) of a saturation magnetization as to a half-width β of a diffraction peak on a (107) plane is 240 emu.Math.g.sup.−1.Math.degree.sup.−1 or more, where the half-width β is determined by X-ray diffraction analysis.

The invention relates to a wire antenna adapted to operate in at least one predetermined frequency band, comprising a plurality of superimposed layers, comprising at least one radiating element placed on a support layer, wherein the support layer is placed on a spacer substrate, and wherein the spacer substrate is placed on a reflector plane comprising at least one resistive layer between the support layer of the radiating element(s) and the substrate spacer, while the resistive layer comprises at least two sets of nested resistive patterns. This antenna is such that the sets of resistive patterns have resistance values gradually varying between a central antenna point and an outer edge of the antenna, in order to achieve a resistance gradient.

The invention relates to a wire antenna adapted to operate in at least one predetermined frequency band, comprising a plurality of superimposed layers, comprising at least one radiating element placed on a support layer, wherein the support layer is placed on a spacer substrate, and wherein the spacer substrate is placed on a reflector plane comprising at least one resistive layer between the support layer of the radiating element(s) and the substrate spacer, while the resistive layer comprises at least two sets of nested resistive patterns. This antenna is such that the sets of resistive patterns have resistance values gradually varying between a central antenna point and an outer edge of the antenna, in order to achieve a resistance gradient.

The present disclosure provides a sub-wavelength structural material having compatibility of low detectability for infrared, laser, and microwave, which includes, from top to bottom, a metal type frequency selective surface layer I, a dielectric layer I, a metal type frequency selective surface layer II, a dielectric layer II, a resistive film, a dielectric layer III. Each of the metal type frequency selective surface layers is a sub-wavelength patch type array, and metal used by the metal type frequency selective surface layers has a characteristic of low infrared emissivity. The present disclosure modulates a phase by using a phase difference generated by patches with different sizes on the metal type frequency selective surface layer I, so as to control backscattering of incident electromagnetic waves to achieve compatibility of low detectability for laser and infrared, while the bottom three layers achieve absorption of microwave.

The present disclosure provides a sub-wavelength structural material having compatibility of low detectability for infrared, laser, and microwave, which includes, from top to bottom, a metal type frequency selective surface layer I, a dielectric layer I, a metal type frequency selective surface layer II, a dielectric layer II, a resistive film, a dielectric layer III. Each of the metal type frequency selective surface layers is a sub-wavelength patch type array, and metal used by the metal type frequency selective surface layers has a characteristic of low infrared emissivity. The present disclosure modulates a phase by using a phase difference generated by patches with different sizes on the metal type frequency selective surface layer I, so as to control backscattering of incident electromagnetic waves to achieve compatibility of low detectability for laser and infrared, while the bottom three layers achieve absorption of microwave.

Provided is a light weight and remarkably flexible sheet-shaped radio wave absorber having excellent radio wave absorbing capacity in milliwave band frequencies. The invention is a milliwave band radio wave absorption sheet comprising a radio wave reflection layer (A), a radio wave absorption layer (B) disposed above the layer (A) so as to be parallel thereto, and a protective layer (C) disposed above the layer (B) so as to be parallel thereto. The layer (B) has, at a frequency of 79 GHz, a dielectric constant, wherein the real part is 10 to 20 and the absolute value of the imaginary part is 4 to 10. The layer (B) has a film thickness of 200 to 400 μm. The absolute value of the imaginary part/real part from the dielectric constant is within a range of 0.30 to 0.60. The layer (C) has, at a frequency of 79 GHz, a dielectric constant, wherein the real part is 1.5 to 8.0 and the absolute value of the imaginary part is less than 1.0, and has a film thickness of 50 to 200 μm. In the milliwave band radio wave absorption sheet, the optical reflectance at an incident angle of 60° is 50% or greater, and the optical reflectance at an incident angle of 20° is 25% or greater. In addition, the invention provides a milliwave band radio wave absorption method using the radio wave absorption sheet, and a radio wave damage prevention method involving the installation of the radio wave absorption sheet.

A measurement device for measuring performance of at least one antenna system in a first frequency band and in a second frequency band. The measurement device including an outer chamber having inwardly radio frequency reflective walls configured to enclose the antenna system, an inner chamber deployable inside the outer chamber, the inner chamber having radio frequency absorptive walls configured to enclose the antenna system, a first test antenna arrangement arranged inside the outer chamber and configured for a measurement operation in the first frequency band, and a second test antenna arrangement arranged inside the inner chamber and configured for a measurement operation in the second frequency band, thereby enabling measuring performance of the antenna system in a reflective radio frequency environment by the first test antenna arrangement and measuring performance in an essentially anechoic radio frequency environment by the second test antenna arrangement.

The present disclosure describes techniques for fabricating a textile article from a laminate formed by curing a reinforced fiber matrix and a resin substrate. The resin substrate may include iron oxide particles, such as iron oxide, Fe.sub.3O.sub.4, that are capable of absorbing and attenuating RF signals within a desired RF signal range, namely 0 GHz-3 GHz, 3 GHz, −8 GHz, and greater than or equal to 10 GHz. The iron oxide particles may include Fe.sub.3O.sub.4Fe, Fe.sub.3O.sub.4Ni, or Fe.sub.3O.sub.4, and/or so forth. Each iron oxide particle is selected based on the RF signal range that the textile article is intended to absorb. In other words, a change in iron oxide particle composition and proportion by volume may impact the RF signals absorbed and attenuated by the textile article.

A filter-antenna and a method for making a filter-antenna. The filter antenna includes a microstrip antenna, such as a patch antenna, integrated with an absorptive (e.g., bandstop) filter for absorbing or dissipating energy.