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.

According to a first aspect of the present invention, there is provide a method of electronically signing content. Content to be signed and an attribute sharing item are presented at a signing device associated with a signer. It is detected that the signer has accessed the attribute sharing item to provide one or more identity attributes which uniquely identify the signer. It is also detected that the signer has initiated a signing action at the signing device. The signing action and the identity attributes are transmitted to a signing service which is configured to create an electronic signature including encrypting the content to be signed and the one or more identity attribute.

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.

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 wireless communication device includes an antenna and is used for storage as an electrical conductive body. The antenna includes a first conductor and a second conductor, one or more third conductors, a fourth conductor, and a feeding line. The first conductor and the second conductor face each other in a first axis. The one or more third conductors are located between the first conductor and the second conductor and extend in the first axis. The fourth conductor is connected to the first conductor and the second conductor and extends in the first axis. The feeding line is connected to any one of the third conductors. The first conductor and the second conductor are capacitively coupled to each other via the third conductor. The fourth conductor faces a conductor part of the storage.

A wireless communication device includes an antenna and is used for storage as an electrical conductive body. The antenna includes a first conductor and a second conductor, one or more third conductors, a fourth conductor, and a feeding line. The first conductor and the second conductor face each other in a first axis. The one or more third conductors are located between the first conductor and the second conductor and extend in the first axis. The fourth conductor is connected to the first conductor and the second conductor and extends in the first axis. The feeding line is connected to any one of the third conductors. The first conductor and the second conductor are capacitively coupled to each other via the third conductor. The fourth conductor faces a conductor part of the storage.

A body part for a motorized land vehicle is provided. The body part includes at least one wall made of a plastic material and including at least one housing forming a cavity for electromagnetic waves, said housing includes: at least one transceiver for transmitting and/or receiving an electromagnetic wave in said housing; at least one adaptable surface capable of reflecting the electromagnetic wave transmitted by the transceiver in a given direction (in a controlled manner) and, conversely, capable of reflecting the electromagnetic wave coming from the exterior of the housing toward the transceiver.

A twin beam base station antenna includes a first array that has a plurality of columns of first frequency band radiating elements, the first array configured to form a first antenna beam that provides coverage throughout a first sub-sector of a three-sector base station. The radiating elements in a first of the columns in the first array have a first azimuth boresight pointing direction and the radiating elements in a second of the columns in the first array have a second azimuth boresight pointing direction that is offset from the first azimuth boresight pointing direction by at least 10°. The radiating elements in the second of the columns in the first array are electrically steered.

A twin beam base station antenna includes a first array that has a plurality of columns of first frequency band radiating elements, the first array configured to form a first antenna beam that provides coverage throughout a first sub-sector of a three-sector base station. The radiating elements in a first of the columns in the first array have a first azimuth boresight pointing direction and the radiating elements in a second of the columns in the first array have a second azimuth boresight pointing direction that is offset from the first azimuth boresight pointing direction by at least 10°. The radiating elements in the second of the columns in the first array are electrically steered.

An aspect of the present disclosure is directed to and provides radar-reflecting systems and apparatus that employ metasurfaces to produce enhanced radar cross sections that are greater than those produced by the geometry of the surfaces alone. Another aspect of the present disclosure is directed to and provides heat-ducting systems and apparatus that include metasurfaces. A further aspect of the present disclosure is directed to and provides cards with metasurfaces. Exemplary embodiments utilize fractal plasmonic surfaces for a metasurface.