Angled RFID Antenna Null Point Reduction
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Solution Overview
Problem
Conventional RFID tag systems experience reading errors due to the generation of null points caused by the combination of direct and reflected radio waves, leading to unstable communication areas, especially in environments with vertical or horizontal surfaces.
Innovation Solution
The RFID tag system incorporates an antenna disposed at a predetermined angle, matching the polarization plane of the radio wave, which reduces the influence of reflected waves from surfaces like floors and walls, thereby minimizing null points and ensuring stable communication without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the RFID tag uses a conventional antenna configuration, then the communication range can be extended to about 5m, but null points are generated due to the combination of reflected waves from surrounding surfaces and direct waves, causing reading errors and unstable communication areas
Solution Approach 1:
The patent applies asymmetry by configuring the antenna at a predetermined angle (e.g., 45 degrees) relative to the longitudinal direction of the tag case, rather than using a symmetric parallel configuration. This angular asymmetry changes the polarization characteristics of the radiated radio waves, reducing constructive interference between direct and reflected waves that causes null points, thereby maintaining communication stability across the extended 5m range.
2Reliability
If additional components are added to prevent null points, then the generation of null points can be prevented, but the device complexity increases
Solution Approach 1:
The patent changes the angular parameter of the antenna configuration from a conventional parallel alignment to a predetermined angle (such as 45 degrees). This parameter modification alters the polarization plane of the radiated radio waves, enabling the system to avoid null points caused by reflected wave interference without adding any physical components, thus preventing null points while maintaining simple device structure.
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
This configuration effectively reduces the occurrence of null points, enabling stable and long-range communication in environments with reflective surfaces, as demonstrated by experimental results showing improved reception levels and reduced null point generation.
Implementation Method 1
The RFID reader/writer and the RFID tag conduct communication with each other using the antenna that transmits and receives the linearly-polarized radio wave having the polarization plane leaned at the predetermined angle with respect to the reflecting surface
Implementation Method 2
a radio wave transmitted from the RFID reader/writer is reflected by a floor or a wall, and the reflected radio wave (a reflected wave) and a direct wave are combined to generate a point (the null point)
Implementation Method 3
the reflected radio wave (a reflected wave) and a direct wave are combined to generate a point (the null point) where a reading error is generated
Data Source
Figure 1
Figure 2~3B
Figure 4~5B
AI summary
An aspect of the present invention provides an RFID tag, in which a null point is hardly generated. The RFID tag includes a long antenna provided in a rectangular surface. The antenna is accommodated in a tag case of the RFID tag, and the antenna extends in a direction oblique to sides constituting the rectangular surface of the tag case.