Ferrite Layer for Wireless Sensor Signal Transmission
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Solution Overview
Problem
Wireless sensors embedded in metallic or highly conductive components face challenges in signal transmission due to eddy-currents that prevent electromagnetic field penetration, making it difficult to read the sensors in environments like aircraft skins or turbine blades.
Innovation Solution
An embedded sensor apparatus is developed with a ferrite layer, which can be a ferrite plug, deposited layer, or metal-ferrite composite, applied using cold spray or thermal spray processes, to facilitate wireless signal transmission by reducing eddy currents and enhancing electromagnetic field penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless sensor is embedded in a metallic or highly conductive component, then the sensor is protected and integrated into the structure, but eddy-currents are generated that prevent electromagnetic field penetration and block signal transmission
Solution Approach 1:
A ferrite layer is introduced as an intermediary material between the conductive substrate and the electromagnetic field. The ferrite layer has high magnetic permeability and electrical resistivity, which allows it to guide magnetic flux while blocking eddy currents. This intermediary enables electromagnetic field penetration to the embedded sensor while preventing harmful eddy-current generation in the conductive substrate.
Solution Approach 2:
The electrical resistivity and magnetic permeability parameters are modified by applying the ferrite coating. The ferrite layer increases the effective electrical resistivity at the surface, reducing eddy-current formation, while its high magnetic permeability enhances magnetic flux concentration, allowing electromagnetic fields to penetrate more effectively to reach the embedded sensor.
2Ease of operation
If a ferrite layer is applied to reduce eddy currents and enable signal transmission, then wireless signal transmission is facilitated, but the device complexity increases due to additional coating processes
Solution Approach 1:
The ferrite coating thickness is optimized to achieve the desired balance between signal transmission and eddy-current reduction. By controlling the thickness parameter within a specific range, the coating provides sufficient electromagnetic shielding and eddy-current suppression while maintaining a relatively simple and cost-effective application process.
3Ease of operation
If the cavity of the substrate is shaped to generate directional tuning, then the wireless sensor transmission directionality is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The cavity is designed with an asymmetric E-shape configuration that creates directional tuning for the wireless sensor. The asymmetric geometry guides electromagnetic fields preferentially in certain directions, enabling directional signal transmission. While this requires precise manufacturing, the design leverages the natural electromagnetic properties of the ferrite material to achieve the desired directional control.
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 ferrite layer allows for effective wireless signal transmission from embedded sensors, enabling condition-based maintenance and adaptive fault-tolerant systems in conductive environments, such as aerospace and transportation industries, by reducing eddy currents and improving sensor readability.
Implementation Method 1
Even the thinnest conductive surfaces may create eddy-currents that prevent significant electromagnetic field penetration
Implementation Method 2
create eddy-currents that prevent significant electromagnetic field penetration
Implementation Method 3
covering the protective cover with the ferrite layer may comprise depositing the ferrite layer on the protective cover using a cold spray process
Implementation Method 4
covering the protective cover with the ferrite layer may comprise depositing the ferrite layer on the protective cover using a thermal spray process
Data Source
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AI summary
An embedded sensor apparatus (100;200;300;400) for enabling wireless signal transmission while protecting an embedded sensor (103) is disclosed. In various embodiments, an embedded sensor apparatus (100;200;300;400) may comprise a substrate (101;301;401) with a cavity (102), a wireless sensor (103) embedded in the cavity (102) of the substrate (101;301;401), a protective cover (104) coupled to the wireless sensor (103), and a ferrite layer (105;205;305;405) covering the protective cover (104). Further, the embedded sensor apparatus (100;200;300;400) may comprise an electromagnetic reflector (106) coupled between the wireless sensor (103) and the substrate (101;301;401). In addition, the ferrite layer (105;205;305;405) may be a ferrite plug (205), a deposited ferrite layer (105;305;405), or a combination thereof. Furthermore, in various embodiments, covering the protective cover (104) with the ferrite layer (105;205;305;405) may comprise depositing the ferrite layer (105;305;405) on the protective cover (104) using a cold spray process. In another embodiment, covering the protective cover (104) with the ferrite layer (105;205;305;405) may comprise depositing the ferrite layer (105;305;405) on the protective cover (104) using a thermal spray process.