RFID Docking Station Antenna Layout for 3D Shelf Interrogation

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Solution Overview

Problem

Existing RFID systems face challenges in providing cost-effective, scalable solutions for three-dimensional interrogation of RFID tags in applications like shelving and storage systems, where items are stacked and orientation is unpredictable, leading to missed identifications and high implementation costs due to complex and expensive antenna arrays.

Innovation Solution

A docking station system with movable antennas that can create a 1, 2, or 3-dimensional interrogation field by integrating with shelving units, allowing for a single docking station to service multiple cabinets, reducing the need for extensive antenna arrays and lowering costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a multiplicity of interrogator coils operating in different coordinate axes is used to achieve three-dimensional interrogation capability, then the ability to identify items in any orientation is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvethree-dimensional interrogation capabilityVSAvoidcomplexity of antenna array
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides the three-dimensional interrogation space into multiple two-dimensional planes. Each plane contains a set of parallel spaced conductors that can be independently controlled. By segmenting the problem into planar components and combining their outputs, the system achieves 3D capability without requiring a full three-dimensional array of coils, thus reducing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses sequential time-based switching of conductors within each plane to create the effect of three-dimensional interrogation. By adding the time dimension to control which conductors are active, the system simulates a three-dimensional field using two-dimensional spatial arrangements, reducing the physical complexity of the antenna structure.

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

2Ease of manufacture

If relatively flat planar antenna coils are used for shelving applications, then the ease of installation and cost are improved, but the three-dimensional interrogation capability is lost

Engineering Contradiction:
Improveease of installationVSAvoidthree-dimensional interrogation capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system merges multiple two-dimensional planar antenna arrays into a three-dimensional interrogation system. By combining the outputs from multiple planes with different orientations and using sequential switching, the system achieves 3D coverage while maintaining the manufacturing and installation simplicity of flat planar coils.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system introduces dynamic temporal control to static planar antenna structures. By sequentially activating different conductors in different planes over time, the system creates a dynamic three-dimensional interrogation capability from static, easily manufactured planar components.

Inventive Principle:
Principle #15Dynamics

3Area of stationary object

If a large array of antennas is deployed to cover extensive shelving areas, then the coverage area is improved, but the cost and device complexity increase

Engineering Contradiction:
Improvecoverage areaVSAvoidnumber of antenna elements
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The system uses a small number of multi-functional antenna planes that can be reconfigured over time to cover different areas. Instead of deploying many fixed antennas simultaneously, the system copies the interrogation function across different spatial planes and time periods, achieving extensive coverage with fewer physical components.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system changes the operational parameters (which conductors are active, their current directions, and timing) to adapt the coverage area dynamically. By varying these parameters, a fixed physical structure can provide flexible coverage over different regions, reducing the need for physically expanding the antenna array.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If sequential switching of currents in parallel spaced conductors is used to create three-dimensional field, then the three-dimensional interrogation capability is achieved, but the parasitic currents from coupling between conductors increase

Engineering Contradiction:
Improvethree-dimensional field capabilityVSAvoidparasitic currents
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The system extracts and compensates for the harmful parasitic currents generated by coupling between conductors. By identifying these parasitic effects and applying compensatory control signals, the system removes their negative impact while maintaining the beneficial three-dimensional field generation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system converts the parasitic currents, which are harmful side effects of conductor coupling, into useful components of the interrogation field. By carefully controlling the timing and magnitude of currents in adjacent conductors, the parasitic fields are transformed into constructive contributions to the overall three-dimensional interrogation capability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 efficient and cost-effective identification of RFID tags in a large number of cabinets with reduced emissions and mechanical complexity, allowing for widespread adoption of RFID technology in applications like warehousing and medical device tracking.

Implementation Method 1

a series of parallel spaced conductors through which currents are sequentially switched in order to produce both tangential and normal magnetic field components

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

radio frequency identification (RFID)... RFID reader... RFID tags

Methodology Applied
Scientific EffectElectromagnetic Radiation:

Data Source

PatentEP2987117B1Interrogator system, apparatus and method
Publication Date: 2019.03.06 SATO HLDG CORP
  • EP2987117B1 patent drawingFigure 1~2
  • EP2987117B1 patent drawingFigure 3~4
  • EP2987117B1 patent drawingFigure 5

AI summary

The present invention relates to the identification of RFID devices that are arranged closely together and placed on shelving for logistical and storage purposes. Furthermore, the aspects of the present invention relate to an arrangement and/or layout of antenna coils for example in an interrogator. There is disclosed a RFID interrogator and/or method of interrogating comprising, in one form, an RFID docking station consisting of a stationary RFID interrogator with RFID shelving antennas and mobile cabinets with shelves where the docking station antennas and the cabinet shelves interpenetrate when the mobile cabinet is offered up to the docking station such that the antennas are able to identify tagged items on the cabinet shelves. In another form, an RFID docking station consisting of a mobile RFID interrogator with RFID shelving antennas and stationary cabinets with shelves where the docking station antennas and the cabinet shelves interpenetrate when the docking station is offered up to the shelving such that the antennas are able to identify tagged items on the cabinet shelves.