Wireless Tag Reader Antenna Dynamics for Metal Container Detection
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Solution Overview
Problem
Conventional wireless tag reading apparatuses are unable to read information from RFID tags outside a metal container and cannot differentiate between tags within a predetermined area for registration and those outside this area.
Innovation Solution
A wireless tag reading apparatus equipped with an antenna, actuator, phase detector, and processor that moves the antenna within a predetermined effective detection region to calculate phase differences and determine the incident angles of response waves, allowing it to register only tags within a defined virtual area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metal container is used to accommodate the tag, then electromagnetic waves are contained within the container allowing simultaneous reading of multiple tags, but tags outside the container cannot be read
Solution Approach 1:
The antenna is made movable along the surface of the container by an antenna drive section, allowing the reading apparatus to dynamically adjust its detection position. This enables the system to read tags at multiple locations by moving the antenna to different positions, thereby expanding the effective reading range while maintaining the ability to read multiple tags.
Solution Approach 2:
The invention transitions from a fixed three-dimensional reading space within the container to a two-dimensional surface scanning approach. By moving the antenna along the container surface in multiple directions, the system creates a virtual detection area that extends beyond the static container interior, enabling reading of tags both inside and outside the container.
2Adaptability or versatility
If the antenna is moved to expand detection area, then tags outside the container can be read, but the system cannot differentiate between tags within the predetermined area and those outside
Solution Approach 1:
A phase detector detects the phase of response waves received by the antenna, and a processor calculates phase differences based on signals received at different antenna positions. This feedback mechanism enables the system to determine the direction and position of tags relative to the antenna, allowing precise identification of whether tags are within the predetermined effective detection area.
Solution Approach 2:
The invention replaces mechanical position detection with electromagnetic phase-based detection. Instead of mechanically tracking tag positions, the system uses phase difference measurements of response waves to calculate incident angles and determine tag locations, achieving more precise and reliable position detection.
3Measurement precision
If electromagnetic shielding is used to contain waves, then reading accuracy within the container is improved, but the system becomes complex and cannot read external tags
Solution Approach 1:
Instead of using static electromagnetic shielding structures, the invention employs a dynamic antenna positioning system that moves along the container surface. This eliminates the need for complex shielding mechanisms while maintaining reading accuracy through controlled antenna movement and phase-based position detection.
Solution Approach 2:
The invention extracts the electromagnetic shielding function from the physical container structure and replaces it with a software-based position determination system. By calculating tag positions using phase differences and incident angles, the system achieves area-specific reading without requiring physical shielding barriers.
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
Enables accurate registration of RFID tags within a specific area while ignoring tags outside this area, improving the efficiency of tag reading and registration processes without the need for a dedicated container or electromagnetic shielding.
Implementation Method 1
an antenna 11 configured to receive a response wave signal from a wireless tag
Implementation Method 2
a phase detector 121 configured to detect a phase of the response wave signal received by the antenna 11
Data Source
AI summary
A wireless tag reading apparatus includes an antenna, an actuator, a phase detector, and a processor. The actuator is configured to move the antenna along a predetermined effective detection region. The processor is configured to calculate a first phase difference based on a phase of a response wave signal received by the antenna at a first plurality of antenna positions, and a second phase difference based on the phase of the response wave signal received by the antenna at a second plurality of antenna positions. The processor is configured to calculate first and second incident angles of the response wave signal for the antenna at the first and second plurality of antenna positions, respectively, based on the first and second phase differences, respectively. The processor is configured to determine whether or not the wireless tag is in the predetermined effective detection region based on the first and second incident angles.