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Contactless tuning adjustment of RFID credentials

IP.com Disclosure Number: IPCOM000198583D
Publication Date: 2010-Aug-10
Document File: 1 page(s) / 72K

Publishing Venue

The IP.com Prior Art Database

Abstract

By bringing another resonator (coil plus capacitor) close to the antenna of the RFID transponder the combined self resonance frequency changes. Since the additional resonator circuit can have a very high quality factor, hardly any power is lost within it. This allows changing the self resonance frequency of the credential by adjusting the self resonance frequency of the resonator circuit close by, which components are easily accessible

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Contactless tuning adjustment of RFID credentials

Abstract:

By bringing another resonator (coil plus capacitor) close to the antenna of the RFID transponder the combined self resonance frequency changes. Since the additional resonator circuit can have a very high quality factor, hardly any power is lost within it. This allows changing the self resonance frequency of the credential by adjusting the self resonance frequency of the resonator circuit close by, which components are easily accessible

In inductive coupled RFID systems, the antenna design and tuning of both reader and transponder are most important for the achieved read range and performance.

The process of optimizing this tuning is significantly easier for readers due to the fact that the components are accessible (at least for the developer). For RFID credentials this is more complicated since those are typically laminated and access to the antenna / transponder chip is not possible.

This means that after production a modification of this parameter is hardly possible and in order to investigate in possible improvements of the credentials performance can only be conducted by starting a new production with estimated parameters.

At this point the idea of contactless adjusting the tuning of the card comes into play.

Beside the physical antenna size and the chip characteristics of a transponder, the self resonance frequency is the most important parameter, which determines the read range and RF characteristics of the t...