UHF RFID Inlay Antenna Pattern for Orientation-Independent Reading
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Solution Overview
Problem
UHF frequency band RFID inlays with conventional dipole antennas experience poor gain and unstable data transmission and reception when the reader/writer is positioned in the same direction as the dipole antenna, leading to orientation and positional relationship issues.
Innovation Solution
An antenna pattern for UHF frequency band RFID inlays is designed with a dipole antenna on the front surface and a sub-element on the back surface, featuring a loop portion with meanders and capacitance hats, and U-shaped sub-elements that are line symmetrical and overlap with the dipole antenna, enhancing directivity and transmission/reception capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dipole antenna is used in the RFID inlay, then the antenna structure is simple, but the gain is poor in the direction in which the dipole antenna extends, resulting in unstable transmission and reception of data
Solution Approach 1:
The patent combines a dipole antenna with a sub-element antenna into a single integrated antenna pattern. The dipole antenna provides omnidirectional coverage in one plane, while the sub-element antenna extends coverage in a perpendicular plane, merging their radiation patterns to achieve three-dimensional omnidirectional communication capability.
Solution Approach 2:
The patent transitions from a two-dimensional dipole antenna radiation pattern to a three-dimensional omnidirectional pattern by adding the sub-element antenna in a perpendicular orientation. This dimensional extension allows the antenna to communicate effectively with readers positioned at various spatial orientations.
2Adaptability or versatility
If a dipole antenna is used in the RFID inlay, then the manufacturing process is simple, but the directivity is poor, causing transmission and reception to fail depending on orientation and positional relationship with the reader
Solution Approach 1:
The antenna pattern serves multiple functions: the dipole antenna component provides omnidirectional coverage in the horizontal plane, while the sub-element antenna component provides coverage in the vertical plane. This multi-functional design enables the single antenna structure to communicate effectively with readers positioned at any orientation or location around the RFID inlay.
3Area of stationary object
If a conventional dipole antenna is used, then the antenna pattern is simple, but the communication range is limited due to poor gain in certain directions
Solution Approach 1:
The patent merges the radiation patterns of two antenna types (dipole and sub-element) to create a combined omnidirectional pattern. This merging of radiation patterns extends the effective communication range in all directions compared to using a single dipole antenna alone.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An antenna pattern (10) used in a UHF frequency band RFID inlay (1) is provided with a substance (11); a dipole antenna (31) formed from a metal foil upon the front surface (11A) of the substance (11); and a sub-element (32) formed from a metal foil upon the back surface (11B) of the substance (11), wherein the dipole antenna (31) is provided with a loop portion (12) having a IC chip connecting portion (101); a pair of meanders (126, 127) configured to respectively extend from the loop portion (12) so as to be line symmetrical; and capasitance hats (128, 129), the sub-element (32) has a pair of U-shapes, and a part of the sub-element (32) overlaps with the dipole antenna (31) through the substance (11).