Electromagnetic Wave Shielding Member for Wideband 60–90 GHz Absorption
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Solution Overview
Problem
Existing electromagnetic wave absorbing materials for millimeter waves exhibit narrowband absorption characteristics and high manufacturing costs due to complex multilayer structures, limiting their practical use and effectiveness in high-frequency bands.
Innovation Solution
An electromagnetic wave shielding member comprising an electromagnetic wave absorbing layer with a dielectric constant of 4 to 30 and a dielectric loss tangent of 0.1 to 2.0, and a reflection layer with a volume resistivity of 1×10−4 to 1×10−1 Ω·cm, containing 1 to 20 wt% electromagnetic wave absorbing filler, achieves wide absorption and shielding characteristics in the 60 to 90 GHz frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer structure with two or more dielectric layers is used to obtain wide band absorption characteristics, then the absorption band width is improved, but the device complexity and manufacturing cost are worsened due to requiring many parameter controls such as dielectric characteristics, film thicknesses, and lamination method
Solution Approach 1:
The patent merges the functions of multiple dielectric layers into a single dielectric layer containing both electromagnetic wave absorbing filler and reflection layer. This integration achieves wide band absorption characteristics (60-90 GHz) while eliminating the complex multilayer structure and its associated parameter control requirements, thus resolving the contradiction between absorption band width and device complexity
Solution Approach 2:
The patent employs composite materials by combining electromagnetic wave absorbing filler with binder resin to form a unified dielectric layer that also serves as the reflection layer. This composite structure enables wide frequency band absorption (20 GHz or more) while maintaining a simple single-layer configuration, thereby improving adaptability without increasing device complexity
2Ease of manufacture
If a N/4 type electromagnetic wave absorbing sheet with dielectric layer and reflection layer is used, then the manufacturing process is simplified, but the absorption performance is limited to narrowband characteristics with attenuation of 10 dB for about 10 GHz band and 20 dB for about 5 GHz band
Solution Approach 1:
The patent changes the key parameters of the dielectric layer by controlling the dielectric constant (4 to 30) and dielectric loss tangent (0.1 to 2.0),以及 the filler content (1 to 20 wt%). These parameter adjustments enable the single-layer structure to achieve wide band absorption characteristics (60-90 GHz frequency band) while maintaining manufacturing simplicity, thus resolving the contradiction between ease of manufacture and absorption band width
3Reliability
If an electromagnetic wave absorbing layer with high dielectric loss is used to improve absorption performance, then the absorption attenuation is improved, but the shielding characteristics in high frequency band of 60 to 90 GHz are worsened due to narrowband limitations
Solution Approach 1:
The patent creates a universal dielectric layer that simultaneously performs electromagnetic wave absorption and reflection functions across a wide frequency band (60-90 GHz). By integrating both absorbing filler and reflection layer into a single layer with optimized dielectric properties (dielectric constant of 4 to 30, dielectric loss tangent of 0.1 to 2.0), the structure achieves multi-functionality that improves both absorption performance and high frequency band adaptability
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 shielding member provides excellent absorption and shielding characteristics in a wide frequency band, allowing for thinner installation and flexibility in accommodating devices with varying frequencies, while reducing manufacturing complexity and costs.
Implementation Method 1
the electromagnetic wave absorbing layer has a dielectric constant of 4 to 30 and a dielectric loss tangent of 0.1 to 2.0
Implementation Method 2
the reflection layer has a volume resistivity of 1×10−4 to 1×10−1 Ω·cm
Data Source
AI summary
An electromagnetic wave shielding member having an electromagnetic wave absorbing layer containing an electromagnetic wave absorbing filler and a binder resin, and a reflection layer disposed on an opposite surface side of an electromagnetic wave incident surface of the electromagnetic wave absorbing layer, wherein the electromagnetic wave absorbing layer has a dielectric constant of 4 to 30 and a dielectric loss tangent of 0.1 to 2.0, the content of the electromagnetic wave absorbing filler is 1 to 20 wt % based on the total weight of the electromagnetic wave absorbing layer, and the reflection layer has a volume resistivity of 1×10−4 to 1×10−1 Ω·cm.