De-Tuned RFID Antenna Array for Gaming Chip Stack Detection

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Solution Overview

Problem

Existing RFID systems struggle to accurately track RFID tags on gaming tables, particularly in roulette, due to closely spaced betting spots, varying stack heights, and the need to distinguish between adjacent bets, leading to inefficiencies and errors in read rates and discrimination.

Innovation Solution

The system employs a de-tuned multiple RFID antenna arrangement with impedance matching tailored for stacks of RFID tags, using reactive tuning components like capacitors and inductors to enhance sensitivity and specificity, and dynamic tuning to adjust for varying stack heights and shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional RFID systems use a single antenna with increased power to extend read range, then the read range is improved, but cross-talk errors increase when multiple antennas are in close proximity

Engineering Contradiction:

Improveread rangeVSAvoidcross-talk errors

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent divides the single antenna into multiple smaller antennas arranged in an array. Each antenna operates at lower power individually, but collectively they cover the required read range. This segmentation eliminates cross-talk errors that occur when a single antenna operates at high power, while still achieving the necessary coverage area for gaming table applications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines multiple low-power antennas into a unified antenna array system that functions as a single reading unit. By merging the capabilities of multiple antennas and coordinating their operation, the system achieves extended read range without the cross-talk problems of individual high-power antennas.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If traditional RFID systems use discrete betting spots with widely separated locations, then cross-talk errors are reduced, but the system cannot track closely spaced bets on roulette tables

Engineering Contradiction:

Improvediscrimination between adjacent betsVSAvoidapplicability to roulette tables

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements different antenna configurations and impedance matching values for different locations on the gaming table. Each antenna in the array is tuned to optimize performance for its specific local area, enabling precise discrimination between closely spaced bets on roulette tables while maintaining overall system reliability.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If traditional RFID systems use fixed impedance matching, then single tag reading is optimized, but stack heights cannot be accurately detected

Engineering Contradiction:

Improvechip stack height detectionVSAvoidimpedance matching configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses multiple antennas with different impedance matching values instead of a single fixed impedance match. By dynamically selecting or combining signals from antennas with varying impedance characteristics, the system can accurately detect chip stack heights while managing the complexity through systematic antenna array design.

Inventive Principle:

Principle #15Dynamics

4Productivity

If traditional RFID systems use single antenna reading, then read time is reduced, but transient events such as chip placement and removal cannot be captured

Engineering Contradiction:

Improveread rateVSAvoiddetection of transient events

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses multiple antennas that can be activated in periodic sequences or simultaneously with different timing. This periodic action allows the system to capture transient events like chip placement and removal by detecting changes across multiple reading cycles, while maintaining high read rates through efficient antenna switching and signal processing.

Inventive Principle:

Principle #19Periodic action

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 approach improves read efficiency, correctly detects chip numbers and colors, distinguishes between adjacent bets, tracks betting habits, and enhances game state monitoring, reducing errors and improving casino operational efficiency.

Implementation Method 1

the excitation antenna defines a 'working volume' within which the energy projected by the antenna is sufficient to power the RFID tag

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

An antenna is impedance matched with a stack of RFID tags with a first impedance matching value, where the first impedance matching value differs from a second impedance matching value for impedance matching the antenna with a single RFID tag

Methodology Applied

Scientific EffectImpedance matching: Capacitance

Implementation Method 3

using reactive tuning components like capacitors and inductors to enhance sensitivity and specificity

Methodology Applied

Scientific EffectInductance: Inductor

Data Source

PatentUS20250342328A1De-tuned multiple RFID antenna arrangement for gaming

Publication Date: 2025.11.06 FORTISS LLC

AI summary

A gaming table contains a number of antennas that are de-tuned from the resonant frequency of a single RFID tag. This increases the power required to read the single tag but matches the resonant frequency for reading a stack of RFID tags. The gaming table may further include an instrumented dolly that manages the game states.