Hybrid RFID Antenna EAS Tag Near Field Read Optimization

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Solution Overview

Problem

Existing EAS/RFID tags face challenges in achieving optimal near field read performance without compromising far field read performance, and are prone to electrostatic discharge (ESD) issues that can lead to chip failure, particularly in combination EAS/RFID applications where close proximity reading is crucial.

Innovation Solution

A combination EAS/RFID security tag design incorporating a hybrid antenna inlay with a magnetic loop antenna situated between two inward spiral antennas, which optimizes near field magnetic performance while maintaining far field response, and includes an impedance matching network using the EAS label to enhance RFID antenna impedance matching, reducing ESD risks by diverting discharge current away from the RFID chip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a spiral antenna is used for RFID tagging, then far field read performance is optimized, but near field read performance is limited

Engineering Contradiction:

Improvenear field read performanceVSAvoidfar field read performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent combines a spiral antenna and a magnetic loop antenna into a hybrid antenna structure. The spiral antenna component optimizes far field read performance while the magnetic loop antenna component enhances near field read performance, particularly in the near field region where magnetic coupling is dominant. This merging allows the single antenna structure to achieve both near field and far field optimization simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If an open antenna structure is used, then near field coupling is improved, but electrostatic discharge can cause chip failure

Engineering Contradiction:

Improvenear field couplingVSAvoidelectrostatic discharge

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes the EAS label's magnetic resonator, which would normally be considered a potential source of electrostatic discharge hazard, and converts it into a beneficial ESD protection mechanism. The magnetic resonator is configured to divert ESD current away from the RFID chip, transforming a harmful factor into a protective feature that prevents chip failure during manufacturing and ultrasonic welding processes.

Inventive Principle:

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

3Adaptability or versatility

If EAS tags are made deactivatable for authorized removal, then tag reuse is enabled, but system complexity increases

Engineering Contradiction:

Improvetag reuse capabilityVSAvoiddeactivation mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the EAS tag and RFID tag into a single integrated security tag structure. The EAS label with magnetic resonator and the RFID label with hybrid antenna are merged into one device, allowing the tag to serve both EAS alarm functions and RFID identification functions. This integration simplifies the overall system by eliminating the need for separate EAS and RFID tags while enabling authorized removal and reuse through the deactivation mechanism.

Inventive Principle:

Principle #5Merging (Combining)

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

The hybrid antenna design improves near field read performance, maintains far field read capabilities, and reduces the likelihood of ESD-induced chip failure, resulting in a more reliable and efficient EAS/RFID tag system with enhanced reading range and durability.

Implementation Method 1

the coupling mechanism depends mainly on the electric E field and not the magnetic H field... the magnetic loop antenna... optimized for both the far field and near field

Methodology Applied

Scientific EffectMagnetic coupling: Magnetic Field

Implementation Method 2

this can cause failure of the device if the level is high enough... reducing ESD (electrostatic discharge) damage to the RFID integrated circuit

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 3

maintains the far field response of the spiral antenna... increases the near field magnetic performance

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP2220596B1Combination EAS and RFID label or tag using a hybrid RFID antenna

Publication Date: 2018.01.10 TYCO FIRE & SECURITY GMBH

Figure 1
Figure 2A~2B
Figure 3A

AI summary

A security tag includes an EAS component having a defined surface area, and an RFID component having a defined surface area. The EAS component surface area is configured to at least partially overlap the RFID component surface area. The RFID component includes an antenna which at least partially overlaps the first surface. A substantially planar spacer having a thickness is at least partially disposed between the defined surface areas of the EAS and RFID components. The RFID element read range is affected and controlled by the spacing between the RFID element and the EAS element. The RFID reader is capable of activating the RFID component when the RFID component is within the read range. The antenna includes a magnetic loop antenna in electrical contact with a spiral antenna to increase near field read response.