Steerable Phase Array Antenna for 3D RFID Tag Tracking

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Solution Overview

Problem

Conventional RFID readers face challenges in accurately locating and tracking multiple RFID tags in proximity, especially in multipath environments, and fail to precisely track three-dimensional movement of tags.

Innovation Solution

A steerable phase array antenna RFID tag locater and tracking system, comprising a phase array steerable antenna, an RFID reader, a beam steering unit, and a control computer, which uses beam steering and triangulation to accurately locate and track RFID tags in three dimensions by generating a focused RF beam and analyzing response signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If conventional RFID readers are used to read tags, then reading can be performed, but the reading distance is limited to less than desired and location precision is insufficient

Engineering Contradiction:
Improvereading distanceVSAvoidlocation precision
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The antenna is divided into multiple independently controllable elements arranged in a phase array configuration, allowing the beam to be segmented and steered electronically to different directions without physical movement, thereby extending effective reading distance while maintaining location precision through directional beamforming

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from omnidirectional or fixed-direction reading to three-dimensional spatial reading by controlling the phase and amplitude of each antenna element, enabling the beam to be directed along elevation and azimuth angles, thus adding dimensional capability to extend reading distance while preserving precision

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If multiple RFID tags are located in proximity or in a multipath environment, then tag density increases, but the ability to locate and track tags with acceptable precision deteriorates

Engineering Contradiction:
Improvenumber of tagsVSAvoidtag location precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The system applies local quality by directing a focused beam toward specific angular positions where tags are detected, concentrating energy locally at each suspected tag location rather than broadcasting omnidirectionally, which enables precise differentiation and tracking of multiple tags even in proximity or multipath environments

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The beam direction is made dynamically adjustable through electronic phase control of antenna elements, allowing the system to rapidly switch beam direction and focus energy on different tags in real-time, enabling precise location and tracking of multiple tags as they move or are distributed in space

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If conventional RFID readers are used, then basic tag reading is achieved, but three-dimensional movement tracking capability is lost or imprecise

Engineering Contradiction:
Improvetracking capabilityVSAvoidthree-dimensional location precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system explicitly adds three-dimensional tracking capability by controlling the beam in both elevation and azimuth dimensions through phase array element control, enabling the reader to determine tags' spatial coordinates (x, y, z) and track their movement through space, transforming basic 1D/2D reading into full 3D tracking

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Productivity

If scanning time is reduced to improve productivity, then fewer tags can be located accurately, but if scanning time increases, then productivity decreases

Engineering Contradiction:
Improvescanning speedVSAvoidtag location accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by pre-calculating and storing the spatial relationships and signal characteristics of multiple tags during an initial scanning phase, then using this stored information to rapidly update tag locations in subsequent scans without repeating full scanning procedures, thereby maintaining accuracy while improving scanning speed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adapts its scanning strategy by focusing the beam only on regions where tags are known to exist or are moving, adjusting beam direction and scanning frequency based on real-time tag positions, which reduces unnecessary scanning while maintaining location accuracy through intelligent resource allocation

Inventive Principle:
Principle #15Dynamics

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 precise three-dimensional location and tracking of RFID tags, even at increased distances, with improved multipath immunity and reduced scanning time, allowing for accurate tracking of tags in motion and enhanced system installation and configuration efficiency.

Implementation Method 1

A steerable phase array antenna, an RFID reader, a beam steering unit... which uses beam steering and triangulation to accurately locate and track RFID tags in three dimensions by generating a focused RF beam

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

beam steering unit... generating a focused RF beam... phase array steerable antenna

Methodology Applied
Scientific EffectPhase interference: Interference

Data Source

PatentEP2188791B1Method of locating and tracking an RFID tag and RFID tag locator and tracking system
Publication Date: 2019.03.13 RF CONTROLS LLC
  • EP2188791B1 patent drawingFigure 1
  • EP2188791B1 patent drawingFigure 2
  • EP2188791B1 patent drawingFigure 3

AI summary

A system for and method of tracking and locating RFID tags, including where at least one steerable phase array antenna may locate the tags associated with items in three dimensions in real time, through the use of a beam steering unit and controller therewith to control the direction of a beam launched by the at least one steerable phase array antenna.