Folded RFID Tag Antenna Design for Extended Reading Distance
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Solution Overview
Problem
Conventional RFID tag antennas face challenges in miniaturization, cost, and bandwidth compatibility across different frequency ranges, leading to increased size and cost, and poor reading distance, especially when switched between regions with different bandwidths.
Innovation Solution
A production process for a microstrip patch RFID tag antenna involving an etching step to form radiation and ground plate patterns on a thin film, a compositing step to adhere the film to a substrate, and a folding step to create a double-layer structure with short-circuit pins, which includes slot structures on the radiation plate to reduce resonant frequency and increase bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness, length and width of the conventional RFID tag antenna are increased to achieve good identification effect, then the reading distance is improved, but the outline dimension and cost are increased
Solution Approach 1:
The patent transitions from a conventional single-layer planar antenna structure to a three-dimensional folded structure. The radiation plate is folded along specific lines to create multiple layers that are stacked and fixed together, effectively utilizing the vertical dimension to increase the electrical length and reading distance without increasing the planar footprint.
Solution Approach 2:
The folded radiation plate structure creates a nested configuration where multiple layers are stacked within a compact space. Each folded layer contains radiation elements that are positioned to work together, effectively nesting multiple functional elements within a small outline dimension while maintaining extended electrical length.
2Reliability
If the thickness, length and width of the conventional RFID tag antenna are increased to achieve good identification effect, then the reading distance is improved, but the cost is increased
Solution Approach 1:
By folding the radiation plate into multiple layers and stacking them, the patent achieves extended electrical length and improved reading distance without increasing the planar material area. This dimensional transformation allows the same amount of material to provide longer effective radiation paths, reducing material costs while maintaining or improving performance.
Solution Approach 2:
The patent changes the structural configuration parameter from a single-layer planar layout to a multi-layer folded structure. This parameter change allows the antenna to achieve longer electrical length (improving reading distance) without proportionally increasing material consumption, thereby reducing overall manufacturing cost.
3Device complexity
If a conventional RFID tag antenna is used, then the structure is simple, but the bandwidth compatibility across different frequency ranges is poor
Solution Approach 1:
The folded multi-layer structure creates multiple radiation paths and resonant modes within a compact structure. By folding along specific lines and stacking layers, the antenna achieves extended electrical length that supports wider bandwidth operation, enabling compatibility with different frequency ranges (e.g., 866-868 MHz in Europe and 902-928 MHz in the USA) without significantly complicating the manufacturing process.
4Length of stationary object
If the dielectric thickness is less than 1 mm, then the antenna is miniaturized, but the reading distance is significantly poor
Solution Approach 1:
The patent uses a thin dielectric substrate (less than 1 mm thick) to achieve miniaturization, then compensates for the reduced reading distance by folding the radiation plate into multiple layers. This creates an extended electrical length through vertical stacking, effectively achieving long reading distance despite the thin substrate thickness.
Solution Approach 2:
The folded radiation plate structure nests multiple layers within the thin substrate thickness, creating extended radiation paths through vertical stacking. This nested configuration allows the antenna to achieve long electrical length and good reading distance while maintaining a compact overall thickness.
Data Source
AI summary
A production process of a tag antenna and a micro strip patch RFID tag antenna. The production process includes: an etching step of etching a metal layer on a thin film material composited with the metal layer to form a thin film (1) with radiation unit patterns (11, 12), short circuit pin patterns (13, 14) and ground plate patterns (15, 16); a compositing step of coating gel on the thin film (1) or a substrate (2) and adhering the thin film (1) to the substrate (2); and a folding step of folding the thin film (1) along an edge of the substrate (2), adhering the short circuit pin patterns (13,14) of the thin film (1) to sides of the substrate (2), folding again the thin film (1) in a same direction, adhering the ground plate patterns (15, 16) to a lower surface of the substrate (2).