Ferromagnetic Coated Antenna Shield for EMI
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Solution Overview
Problem
Implantable medical devices (IMDs) face interference from electromagnetic interference (EMI) that can disrupt telemetry signals, affecting communication between IMDs and external programmers.
Innovation Solution
A telemetry head with a ferromagnetic shielding material coating applied to a shield surrounding the antenna, allowing magnetic-field telemetry signals to pass through while shielding against electrical-field interference, ensuring reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is placed around the telemetry antenna to block EMI, then electromagnetic interference shielding is improved, but magnetic-field telemetry signals are blocked
Solution Approach 1:
The shield is selectively coated with ferromagnetic material only on specific surfaces (inner, outer, or both) depending on the interference environment. This localized application of shielding material provides EMI protection in critical areas while maintaining magnetic signal transmission capabilities where coating is not applied.
Solution Approach 2:
The shield combines non-ferromagnetic base material with ferromagnetic coating material to create a composite structure. The non-ferromagnetic base allows magnetic field penetration, while the ferromagnetic coating provides electrical field shielding, achieving both EMI protection and telemetry signal transmission.
2Object-affected harmful factors
If a ferromagnetic coating is applied to the shield, then electrical-field EMI shielding is improved, but magnetic-field signal passage may be affected
Solution Approach 1:
The ferromagnetic coating is applied selectively to specific surfaces of the shield (inner surface, outer surface, or both) based on the dominant interference source location. This localized coating approach provides electrical-field shielding where needed while maintaining magnetic signal transmission paths.
Solution Approach 2:
The coating's electrical conductivity and magnetic permeability parameters are carefully controlled to provide adequate electrical-field shielding while maintaining sufficient magnetic field penetration. The coating thickness and material composition are optimized to balance EMI rejection with telemetry signal transmission.
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 effectively reduces EMI interference, maintaining the integrity of telemetry signals and enhancing communication between IMDs and programmers, thereby improving the reliability and security of data transmission.
Implementation Method 1
A coating comprising a ferromagnetic shielding material is applied to at least a portion of the shield, wherein the coating is configured to permit passage of telemetry signals, such as inductive (magnetic field) telemetry signals, while shielding at least a portion of the antenna from EMI such as electrical fields
Data Source
AI summary
A telemetry head for communication with an implantable medical device comprises a telemetry antenna and a shield substantially surrounding at least a portion of the antenna, the shield having a coating comprising a ferromagnetic material applied to at least a portion of the shield, wherein the coating is configured to shield at least the portion of the telemetry antenna from electromagnetic interference fields while permitting telemetry signals to pass through the coating.