Millimeter Wave Absorber Composite With Low Reflection
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Solution Overview
Problem
Current electromagnetic wave absorber materials are either transparent or reflective for radiation in the 60-90 GHz frequency range, leading to unwanted electromagnetic interference, and existing solutions suffer from anisotropy and mechanical limitations, such as waste generation during sample cutting from semi-finished goods.
Innovation Solution
A millimeter wave absorber material comprising a combination of electrically conductive fillers with specific aspect ratios and an injection moldable matrix, which reduces anisotropy and enhances absorption without significant reflection, using a mixture of fibrous and particulate forms within a polymeric matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If current electromagnetic wave absorber materials are used, then the material structure is simple, but the material is transparent or reflective for radiation in the 60-90 GHz frequency range, leading to unwanted electromagnetic interference
Solution Approach 1:
The patent employs a composite material system consisting of an electrically non-conductive polymer matrix combined with two distinct types of electrically conductive materials: fibrous particles with aspect ratio ≥5 and particulate material with aspect ratio <5. This composite structure enables effective electromagnetic wave absorption in the 60-90 GHz frequency range by creating multiple interaction mechanisms between the different filler types and the polymer matrix, thereby reducing electromagnetic interference while maintaining manageable material complexity through systematic composition design.
2Ease of manufacture
If semi-finished goods are used as a base, then the manufacturing process is simpler, but sample cutting creates much more waste and geometry is limited to 2 dimensional semi-finished goods
Solution Approach 1:
The patent utilizes injection molding technology to transform the manufacturing approach from cutting 2D semi-finished goods to forming 3D components directly. By changing the manufacturing parameter from subtractive cutting to additive molding, the process achieves geometric flexibility for complex three-dimensional shapes while significantly reducing material waste. The injection moldable composition allows direct formation of final product geometries, eliminating the need for wasteful sample cutting operations.
3Object-affected harmful factors
If only one type of conductive material is used, then the material composition is simpler, but the absorption performance and mechanical properties are limited
Solution Approach 1:
The patent segments the conductive filler system into two distinct functional components: fibrous particles with aspect ratio ≥5 that provide structural framework and primary conduction pathways, and particulate material with aspect ratio <5 that fills interstitial spaces and creates additional conduction networks. This segmentation allows each component to optimize its specific function while working synergistically, achieving superior electromagnetic wave absorption performance across the 60-90 GHz range without requiring overly complex multi-component systems.
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 high absorption with low reflection and improved mechanical properties, reducing anisotropy and enabling the use of the material in constructional elements like sensors and radar absorbers, suitable for frequencies between 60 GHz to 200 GHz.
Implementation Method 1
The absorber material is preferably capable of absorbing electromagnetic waves in a frequency region of 60 GHz to 200 GHz
Implementation Method 2
The electromagnetic millimetre wave absorber material comprises based on the total amount of the absorber material from 30 wt.-% to 93 wt.-% of the electrically non-conductive polymer, from 6.5 wt.-% to 10 wt.-% of the first electrically conductive material, from 0.5 wt.-% to 0.9 wt.-% of the second electrically conductive material
Data Source
AI summary
The present invention relates to an electromagnetic millimetre wave absorber material, preferably having a volume resistivity of more than 1 Ωcm, containing solid particles having an aspect ratio (length:diameter) of at least 5 of a first electrically conductive material, particles having an aspect ratio (length:diameter) of less than 5 of a second electrically conductive material and an electrically non-conductive polymer, wherein the absorber material is preferably capable of absorbing electromagnetic waves in a frequency region of 60 GHz to 200 GHz and wherein the electromagnetic millimetre wave absorber material comprises based on the total amount of the absorber material from 30 wt.-% to 93 wt.-% of the electrically non-conductive polymer, from 6.5 wt.-% to 10 wt.-% of the first electrically conductive material, from 0.5 wt.-% to 0.9 wt.-% of the second electrically conductive material, and from 0 wt.-% to 59.1 wt.-% of one or more additives. The invention also relates to its use and method for absorbing as well as a sensor apparatus comprising said absorber material.