RFID Reader Antenna Array for Game Piece Orientation Detection
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Solution Overview
Problem
Conventional RFID systems are unable to detect the orientation of game pieces, such as cards or tokens, which can be face-up, face-down, or rotated, limiting their functionality in tracking and identification applications.
Innovation Solution
An RFID system with a reader coupled to a plurality of antennas arranged in a geometric pattern on a detection surface, where the reader consecutively activates each antenna to determine the alignment with tag antennas on game pieces, allowing for orientation detection by identifying unique subsets of aligned antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RFID systems use a single reader and tag configuration, then the system structure remains simple, but the system cannot detect the orientation of game pieces
Solution Approach 1:
The reader antenna is divided into multiple segments arranged in a geometric pattern (e.g., four antennas at corners of a square). Each antenna segment can independently detect tag signals, and by determining which segments detect the tag, the system can calculate the tag's orientation without adding complex external sensors.
Solution Approach 2:
The geometric arrangement of multiple reader antennas acts as an intermediary structure that enables orientation detection. The spatial relationship between antennas and the detected tag creates a reference frame that allows the system to infer orientation from signal detection patterns, avoiding direct mechanical or optical orientation sensing.
2Adaptability or versatility
If multiple reader antennas are used to detect orientation, then orientation detection capability is improved, but the device complexity increases
Solution Approach 1:
The multiple reader antennas serve dual functions: they simultaneously perform tag identification (standard RFID function) and orientation detection (additional function). The same antenna elements that detect tag presence also provide spatial information for orientation calculation, eliminating the need for separate orientation sensing hardware.
Solution Approach 2:
The system transitions from one-dimensional tag identification to two-dimensional orientation detection by arranging antennas in a geometric pattern across the detection surface. This spatial dimensionality allows the system to determine not just presence but also angular position and face-up/face-down orientation of tags.
3Measurement precision
If tags are placed in multiple locations on game pieces, then orientation detection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The system is designed to work with asymmetric tag placements, where tags can be located at different positions (corners, edges, or centers) on game pieces. The reader's geometric antenna array can detect and calculate orientation regardless of the specific tag position, allowing manufacturing flexibility without compromising detection accuracy.
Solution Approach 2:
The system accommodates variations in tag placement parameters (position, orientation, number of tags) by using the geometric relationship between multiple reader antennas and the detected tag. The orientation calculation algorithm can adapt to different tag configurations, maintaining accuracy across various manufacturing scenarios.
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 the accurate detection of multiple orientations of game pieces, including face-up, face-down, and rotated positions, enhancing tracking and identification capabilities in applications like board games.
Implementation Method 1
A reader includes a transmitter for transmitting an interrogation signal to the tag and a receiver for receiving a response signal from the tag
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3D
AI summary
Embodiments of a radio frequency identification (RFID) reader are provided herein, which include an RFID interrogator; a detection surface for a game piece, the detection surface comprising a plurality of reader antennas in a geometric arrangement; and antenna switching circuitry coupled between the RFID interrogator and the plurality of reader antennas; wherein the antenna switching circuitry is configured to consecutively activate each one of the plurality of reader antennas for at least a detection time window, and wherein the RFID interrogator is configured to: for each reader antenna, detect whether a response signal is received by the reader antenna during the detection time window, and determine a geometric orientation of the game piece based on a subset of reader antennas that received the response signal.