Metal-Mount RFID Antenna Structure With Asymmetric Insulated Layers
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Solution Overview
Problem
Conventional RFID devices operating in the UHF range are ineffective in metal environments due to electromagnetic scattering and coupling, leading to operational failures and complex manufacturing processes.
Innovation Solution
An RFID device design featuring asymmetrically arranged metal layers on a substrate with adhesive areas for electrical insulation, allowing the device to function effectively in metal environments and simplifying the manufacturing process by eliminating the need for folding or complex electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional UHF antenna structures are used on metal surfaces, then manufacturing is simplified, but electromagnetic scattering and coupling cause the RFID device to become inoperative
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the antenna structure and the metal surface. This dielectric layer acts as a mediator that prevents direct electromagnetic coupling between the antenna and the metal surface, thereby eliminating the harmful scattering and coupling effects while allowing the antenna to maintain its simplified planar structure for easy manufacturing.
Solution Approach 2:
The antenna structure employs asymmetric design where the radiating element and ground plane are positioned at different heights above the metal surface, separated by dielectric layers of different thicknesses. This asymmetric configuration disrupts the symmetric electromagnetic field distribution that would otherwise cause strong coupling with the metal surface, improving RFID operation effectiveness while maintaining manufacturing simplicity.
2Reliability
If metal layers are folded to cover multiple surfaces of the substrate, then antenna performance is improved, but manufacturing complexity increases due to folding and machining operations
Solution Approach 1:
Instead of folding metal layers to cover multiple surfaces (three-dimensional configuration), the invention transitions to a planar two-dimensional configuration where the antenna elements are arranged on a single flat substrate. This dimensional simplification eliminates the need for folding and machining operations while maintaining effective antenna performance through optimized planar geometry and dielectric layering.
Solution Approach 2:
The antenna structure is segmented into distinct functional layers: radiating elements, ground planes, and dielectric layers, all arranged in a planar configuration. This segmentation allows each component to be independently optimized and manufactured using simple printed circuit board techniques, eliminating the need for complex folding operations while achieving the desired antenna performance.
3Device complexity
If dipole antenna is arranged on top of metal object, then structure is simplified, but reverse current induction eliminates electromagnetic wave propagation
Solution Approach 1:
Dielectric layers are positioned between the dipole antenna elements and the metal surface to prevent direct electromagnetic coupling. These dielectric intermediaries block the induction of reverse currents in the metal surface by decoupling the antenna's electromagnetic field from the conductive metal, thereby maintaining electromagnetic wave propagation capability while keeping the antenna structure simple.
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 enhances interrogating distance and simplifies manufacturing, ensuring effective RFID operation on metal surfaces with improved antenna gain and reduced capacitive interference.
Implementation Method 1
enable the first metal layer and the second metal layer to be adhered to each other with electrical insulation effect
Implementation Method 2
when the uniform electromagnetic wave is obliquely projected onto a flat antenna formed by a good conductor, a reflection phenomenon from the surface of the good conductor will be generated
Implementation Method 3
it will also cause destructive interference due to the phase variation between the incident electromagnetic wave and reflected electromagnetic wave
Implementation Method 4
due to the characteristic of electromagnetic scattering and coupling, the RFID is sensitive to the liquid and metal environment where it is arranged
Data Source
AI summary
The present invention provides a RFID device arranged on an object surface, comprising a substrate, a first metal layer and a second metal layer. The first metal layer has a first connecting surface having a first adhering layer for adhering to the first surface of the substrate, wherein a RFID element is electrically connected to the first metal layer and a length of the first metal layer is larger than a length of the substrate such that the first metal layer has a first extending part extending outwardly from the lateral surface of the substrate. The second metal layer has a second connecting surface having a second adhering layer formed thereon for adhering the second metal layer on the second surface, wherein the first extending metal layer is attached onto but electrically insulated from the object surface or the second metal layer.