Miniaturized Planar Inverted Folded Antenna for Mountable UHF Tags
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Solution Overview
Problem
Conventional RFID tags, especially UHF dipole-like inlay tags, fail to maintain reliable performance when mounted on objects with varying dielectric values such as metallic materials, meat, or liquids, as they become detuned and are often undetectable by RFID readers due to material loading effects.
Innovation Solution
A low-profile, low-cost folded planar antenna device with a binocular-shaped slot and a substrate, including a PET layer and paper layers, is designed to provide improved RF performance. The antenna is flexible, with a conductor member made of aluminum and dents that adjust resonance, and is capable of balancing microstrip impedance, allowing reliable detection on various objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard UHF dipole-like inlay tags are used, then the RFID tag can be manufactured with conventional designs, but the tag becomes detuned and undetectable when mounted on objects with varying dielectric values such as metal, meat, or liquids
Solution Approach 1:
The antenna is divided into multiple conductive segments separated by dielectric material, forming a folded planar structure. This segmentation allows the antenna to maintain its resonant characteristics when mounted on objects with varying dielectric values, as each segment can be independently optimized and the overall structure is less sensitive to material loading effects.
Solution Approach 2:
The antenna transitions from a conventional planar inlay design to a three-dimensional folded planar structure by wrapping the conductive layer around a dielectric substrate. This dimensional change creates a more robust resonant structure that maintains detection reliability across different mounting surfaces with varying dielectric properties.
2Adaptability or versatility
If an RFID tag is placed directly on a product with varying dielectric values, then the tag can be mounted on diverse products, but the resonant characteristics and radiation performance are affected
Solution Approach 1:
A dielectric substrate is introduced as an intermediary layer between the conductive antenna elements and the product surface. This intermediary provides a stable reference plane for the antenna resonance, isolating the resonant characteristics from the varying dielectric values of different products while still allowing the tag to be mounted on diverse surfaces.
Solution Approach 2:
The antenna structure uses a composite of conductive material (aluminum or copper) and dielectric material (PET or paper layers) to create a folded planar configuration. This composite structure provides both mechanical stability and electromagnetic performance consistency across different mounting conditions.
3Volume of moving object
If a low profile antenna design is used, then the tag can be mounted on various objects, but the antenna performance may be compromised
Solution Approach 1:
The folded planar antenna structure creates a dynamic current path that effectively increases the electrical length of the antenna within a compact physical footprint. By folding the conductive layer around the dielectric substrate, the antenna achieves resonant frequencies appropriate for UHF RFID while maintaining a low profile suitable for mounting on various objects.
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 folded planar antenna device achieves improved RF performance, maintaining reliable detection and resonance across different objects, with enhanced power transmission, return loss, and activation distance, even on challenging materials like metal, meat, and liquids, ensuring consistent RFID functionality.
Implementation Method 1
the length of each of the plurality of dents determines the amount of antenna resonance
Implementation Method 2
Radio frequency identification (RFID) is a technology for the security devices that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum
Implementation Method 3
The conductor member is folded around the substrate. In an example embodiment for the folded planar antenna device, the substrate comprises a polyethylene terephthalate (PET) layer, an outer paper layer and an inner paper layer
Data Source
AI summary
A folded planar antenna device for radio frequency identification (RFID) reading is provided. The folded planar antenna device includes an RFID chip, a conductor member comprising a binocular-shaped slot; and a substrate. The conductor member is mounted on the substrate and the substrate is connected to the RFID chip through the binocular-shaped slot. The folded planar antenna device can be mounted on different objects, such as metal, meat, or liquid container, without being completely de-tuned.