Millimeter Wave Absorption Sheet with Optimized Dielectric Layers
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Solution Overview
Problem
Conventional radio wave absorbers face challenges in providing effective absorption in the millimeter wave band, particularly in terms of lightweightness, flexibility, and wide bandwidth absorption, as well as handling and manufacturing complexities, especially when attached to curved surfaces.
Innovation Solution
A radio wave absorption sheet comprising a radio wave reflection layer, a radio wave absorption layer with specific relative permittivity and film thickness, and a protective layer, optimized for the millimeter wave band, ensuring efficient absorption and flexibility by controlling the permittivity, film thickness, and optical reflectance of each layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyramidal radio wave absorbers are used to achieve wide band absorption, then radio wave absorption performance is improved, but the absorbers become bulky and difficult to handle and install
Solution Approach 1:
The patent replaces bulky pyramidal structures with thin film absorbers having a thickness of 100 μm or less. The absorber is formed as a flexible thin film that can be easily handled, transported, and installed on various surfaces including curved surfaces, while maintaining effective radio wave absorption through optimized dielectric material composition and controlled thickness.
Solution Approach 2:
The patent changes the physical parameters of the absorber by controlling the thickness to 100 μm or less and adjusting the dielectric constant of the material. This parameter optimization allows the thin film to achieve effective absorption in the 76-81 GHz band while maintaining flexibility and ease of handling, resolving the contradiction between absorption performance and ease of operation.
2Reliability
If pyramidal radio wave absorbers are used to achieve wide band absorption, then radio wave absorption performance is improved, but manufacturing steps become complex
Solution Approach 1:
The patent simplifies manufacturing by producing the absorber as a thin film rather than forming complex pyramidal structures. This approach reduces the number of manufacturing steps, eliminates the need for complex molding and assembly processes, and allows for more straightforward production while achieving the required absorption performance through material composition and thickness control.
Solution Approach 2:
The patent uses composite dielectric materials with specific properties (dielectric constant between 2.0-10.0) to achieve effective absorption in a thin film structure. This material approach simplifies manufacturing compared to constructing pyramidal shapes, as the absorption performance is achieved through material composition rather than complex geometric structures.
3Reliability
If conventional stacked radio wave absorbers are used, then absorption in specific frequencies is achieved, but absorption frequency bandwidth is insufficient
Solution Approach 1:
The patent achieves wide bandwidth absorption (76-81 GHz) by optimizing the dielectric constant of the material to be between 2.0-10.0 and controlling the thickness to 100 μm or less. This parameter optimization allows a single-layer thin film structure to provide effective absorption across the entire C-band millimeter wave range, eliminating the need for complex multi-layer stacked structures.
Solution Approach 2:
The patent achieves wide bandwidth absorption with a simple single-layer structure by using dielectric material with specifically optimized local properties (dielectric constant between 2.0-10.0). This localized material property optimization allows the thin film to effectively absorb across the 76-81 GHz band without requiring complex multi-layer stacking, thus reducing device complexity while maintaining broad frequency coverage.
4Ease of operation
If radio wave absorbers are made lightweight and flexible, then handling and installation are improved, but absorption performance in milliwave band may be compromised
Solution Approach 1:
The patent achieves both lightweight flexibility and effective absorption performance by optimizing the thickness to 100 μm or less and selecting dielectric material with dielectric constant between 2.0-10.0. These parameter optimizations ensure that the thin, flexible structure maintains effective absorption in the 76-81 GHz milliwave band, resolving the contradiction between ease of operation and absorption performance.
Solution Approach 2:
The patent uses a thin film structure with thickness of 100 μm or less that provides both flexibility for easy handling and installation, and effective radio wave absorption through optimized material composition. The thin film design inherently provides lightweight and flexible characteristics while the controlled dielectric properties ensure adequate absorption performance in the milliwave band.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves excellent radio wave absorption performance in the 76 to 81 GHz range, providing a wide bandwidth, flexibility, and improved handling and manufacturing ease, while preventing electromagnetic interference.
Implementation Method 1
a radio wave absorption layer (B) situated parallel to the top of the radio wave reflection layer (A), wherein: the real part of the relative permittivity of the radio wave absorption layer (B) at a frequency of 79 GHz is in the range of 10 to 20, the absolute value of the imaginary part is in the range of 4 to 10
Implementation Method 2
a radio wave reflection layer (A), a radio wave absorption layer (B) situated parallel to the top of the radio wave reflection layer (A)
Data Source
AI summary
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.