RFID Chip Frequency Tuning for Metal Packaging

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Solution Overview

Problem

Aluminium composite pouches with conductive metal outer casings pose a barrier to radiofrequency identification (RFID) due to the skin effect, preventing the use of RFID chips for identifying contents or monitoring conditions within the packaging without destroying the packaging.

Innovation Solution

Incorporating an RFID chip with a switching circuit and antenna structure operating at frequencies below the blocking frequency determined by the metal casing's conductivity and thickness, allowing non-destructive identification and moisture sensing within aluminium composite pouches using LF-RFID or HF-RFID chips, and employing a capacitor structure for humidity measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminium composite pouches with conductive metal outer casings are used to achieve high barrier qualities against moisture and gases, then packaging protection is improved, but RFID identification becomes impossible due to the skin effect blocking electromagnetic signals

Engineering Contradiction:

Improvepackaging protectionVSAvoidRFID identification capability

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent changes the operating frequency parameter of the RFID system from conventional high frequencies (where the skin effect blocks signals) to low frequencies below the blocking frequency determined by the metal casing's conductivity and thickness. This parameter change allows electromagnetic signals to penetrate the conductive metal outer casing, enabling RFID chips to communicate with scanners while the packaging maintains its high barrier qualities against moisture and gases.

Inventive Principle:

Principle #35Parameter changes

2Loss of information

If conventional RFID chips operating at standard frequencies are used, then identification capability is achieved, but the conductive metal outer casing blocks the signals due to the skin effect

Engineering Contradiction:

Improveidentification capabilityVSAvoidsignal blocking

Core Design Contradiction:

Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by operating the RFID chip at low frequencies below the blocking frequency rather than at conventional RFID frequencies. This frequency parameter change allows the electromagnetic signals to penetrate the conductive metal outer casing, overcoming the signal blocking effect while maintaining identification capability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful skin effect into a beneficial guide by determining the blocking frequency based on the metal casing's conductivity and thickness. By operating below this blocking frequency, the system transforms the previously problematic electromagnetic blocking into a defined operating parameter, enabling reliable RFID communication through the metal packaging.

Inventive Principle:

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

3Speed

If the operating frequency is increased to improve signal penetration, then identification range is improved, but the skin effect blocks the signal more strongly in conductive metal packaging

Engineering Contradiction:

Improvesignal penetrationVSAvoidskin effect blocking

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional approach by using low frequencies instead of high frequencies for RFID operation. While conventional RFID systems use high frequencies to achieve signal penetration, this patent demonstrates that low frequencies below the blocking frequency actually penetrate conductive metal casings more effectively, reversing the typical frequency-selection logic.

Inventive Principle:

Principle #13The other way round (Inversion)

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 reliable, non-destructive identification and moisture sensing of pharmaceuticals in aluminium composite pouches, ensuring accurate and cost-effective monitoring of packaging conditions without compromising the packaging integrity.

Implementation Method 1

the use of RFID chips for identification or monitoring of the conditions within packages with a conductive metal outer casing has not hitherto been possible as the so-called skin effect prevents the outer casing from being penetrated

Methodology Applied

Scientific EffectSkin effect: Skin Effect

Implementation Method 2

a transmitting/receiving unit for sending a transmission signal and/or receiving a response signal from the RFID chip

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentUS8912891B2Apparatus having at least one packaging unit with an RFID chip which is used for radio-frequency identification, and method therefor

Publication Date: 2014.12.16 BOEHRINGER INGELHEIM INT GMBH

AI summary

An apparatus having at least one RFID chip (30), which is surrounded by a metallic outer casing (11) of a packaging unit (1), used for radio-frequency identification and having a circuit (32) and an antenna structure (31), and a transmitting/receiving unit (41) for transmitting a transmission signal (42) and/or receiving a response signal (43) from the RFID chip (30), wherein the response signal (43) can be evaluated using an evaluation unit (44) which is connected to the transmitting/receiving unit (41), where the RFID chip (30) has an operating frequency in a frequency band (50) below a range of a blocking frequency (54) which is determined by the conductivity of the metallic outer casing (11) and the thickness thereof.