Adaptive RF Shielding Mesh for Transparent Sensor Windows
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Solution Overview
Problem
Existing electromagnetic shielding screens for vehicular optronic equipment provide predefined and constant shielding effectiveness, requiring external power for impedance modulation and are not self-adaptive to varying electromagnetic interference levels.
Innovation Solution
A self-adaptive electromagnetic shielding device with a switchable RF shielding mesh and insulator-metal transition material, activated by a susceptor element that converts electromagnetic energy into heat to transition the material to a conductive state, automatically adjusting shielding effectiveness based on incident energy levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a predefined and constant shielding effectiveness is provided using a metal mesh, then electromagnetic protection is ensured, but the shielding cannot adapt to varying electromagnetic interference levels
Solution Approach 1:
The patent applies the dynamics principle by making the shielding effectiveness switchable between different states. The electrically conductive mesh can transition between connected and disconnected states from the ground, allowing the shielding to dynamically adapt to varying electromagnetic interference levels rather than remaining static.
Solution Approach 2:
The patent changes the electrical parameter (contact impedance) of the shielding system to achieve adaptability. By controlling whether the mesh is electrically connected to ground or isolated, the shielding effectiveness parameter can be switched between high and low states, enabling adaptation to different interference conditions.
2Adaptability or versatility
If localized components such as PIN, MEMS, NEMS, or diodes are implanted to modulate shielding effectiveness, then switchable RF shielding is achieved, but external power supply and system complexity increase
Solution Approach 1:
The patent applies the self-service principle by using the electromagnetic energy itself as the triggering mechanism for switching. The susceptor material converts incident electromagnetic energy into thermal energy, which automatically triggers the insulator-metal transition without requiring external power supplies, control circuits, or active components.
Solution Approach 2:
The patent converts the harmful electromagnetic interference into a beneficial switching mechanism. The incident electromagnetic energy, which would otherwise be harmful to the sensor, is converted by the susceptor into thermal energy that triggers the protective shielding state, turning the harmful input into the activation mechanism for protection.
3Adaptability or versatility
If insulator-metal transition material is used to control contact impedance, then shielding effectiveness can be modulated, but the material requires activation energy for state transition
Solution Approach 1:
The patent uses the incident electromagnetic energy, which represents harmful interference, as the source of activation energy for the insulator-metal transition. The susceptor material absorbs this electromagnetic energy and converts it to thermal energy, providing the necessary activation energy to switch the shielding state without requiring external power.
Solution Approach 2:
The patent utilizes the phase transition phenomenon of insulator-metal transition materials. These materials can reversibly switch between insulating and metallic states in response to temperature changes, enabling the shielding effectiveness to be modulated through thermal activation from the susceptor element.
4Illumination intensity
If the shielding screen maintains high optical transparency, then sensor operation is optimized, but electromagnetic shielding effectiveness may be reduced
Solution Approach 1:
The patent uses composite material structures combining transparent substrates with electrically conductive meshes. The mesh is designed with specific geometric parameters (micrometric pitch, strip width, thickness) to provide electromagnetic shielding while maintaining optical transparency. The composite structure leverages the transparency of the substrate and the shielding properties of the conductive mesh.
Solution Approach 2:
The patent applies local quality by making the shielding properties location-dependent and state-dependent. The electrically conductive mesh provides shielding only in specific regions and only when electrically connected to ground. The shielding effectiveness is locally activated around the sensor area when needed, rather than providing uniform shielding across the entire structure.
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 device automatically switches between transparent and shielding states, maintaining high optical transparency and effective electromagnetic protection without external power, with adjustable shielding effectiveness across a wide frequency band.
Implementation Method 1
a susceptor element, arranged facing or in contact with the insulator-metal transition material and adapted to transform incident electromagnetic energy into an amount of activation heat for the insulator-metal transition material
Implementation Method 2
insulator-metal transition material, typically VO2, whose two states, ON (electrically conductive) and OFF (electrically insulating), strongly modify the value of the contact impedance of the screen with the ground
Data Source
AI summary
A self-adaptive shielding device is suitable for a lens or a window of a piece of equipment provided with an electrically conductive enclosure containing an optical or RF sensor. The device includes a shielding screen having a switchable RF shielding mesh of micrometric pitch at least partially surrounded by a border of insulator-metal transition material arranged between the mesh and an electrically conductive envelope. A susceptor element is arranged facing the insulator-metal transition material and transforms incident electromagnetic energy (RFH) into activation heat for the insulator-metal transition material. The susceptor element causes a transition to the conductive state of the insulator-metal transition material under the action of the electromagnetic energy so as to electrically connect the mesh to the electrically conductive envelope when the incident electromagnetic energy exceeds a given threshold.