RFID (Contactless IC cards, Contactless IC tags)

How are RFID regulated?

The operating frequencies of RFIDs, which are also known as IC tags or contactless IC cards, are defined by international standards. When performing L measurement of a board used by a contactless IC card, the measurement must be made near the operating frequency of 13.56 MHz.

Setting example of measurement conditions

Measurement modeANALYZER
ParametersZ-θ  frequency characteristics analysis(L-Q、R evaluation available)
Sweep parameterFREQ
Sweep frequencySweep measurement close to the operating frequency (See the table below)
Signal levelV mode 1V (350x, IM35xx series) or 1dBm (IM758x series)
*The above settings apply to an example measurement. Since optimal conditions vary with the measurement target, specific settings should be determined by the instrument operator.

RFID standards

CategoryFrequencyEffective distanceStandard
ID cards13.56MHzUp to 10cm
 (Proximity applications)
ISO 14443
Automatic recognition125kHzUp to 70cm (Vicinity applications)ISO 14443
13.56MHzISO 15693

Structure of RFID tags

RFIDs generally consist of an antenna and IC. Signal transmission is accomplished by a resonant circuit formed by the antenna inductor (Ls) and the IC chip’s built-in input capacitance (Cp).

Frequency characteristics of defective and non-defective components

As shown in the figures, the Z-θ frequency characteristics of defective and non-defective components differ. The non-defective component exhibits a resonance point near the operating frequency.

Instruments for Research & Development Applications

ModelMeasurement frequencyRFID
IM758x series100k to 1.3GHz *Mainly for high-frequency RFID
IM35704Hz to 5MHzMainly for low-frequency to medium frequency RFID
*For more information, please see the product catalog.

Pass/fail judgments using analyzer mode

Either of two methods can be used to generate pass/fail judgments when using analyzer mode: peak judgment and area judgment.

How to set the judgment area

Judgement areas can be set as follows.
• A known-good element’s measured value can be used as the reference (±10% of the reference element’s measured value, etc.).
• A user-specified value can be entered (1 k±10%, etc.).  

Ascertaining electrical constants by means of equivalent circuit analysis

The instrument’s equivalent circuit analysis function can be   used to calculate the constants in a three-terminal circuit model such as an RFID antenna.
*Model A should be used for coils with a large core loss (R) in order to facilitate more accurate analysis.

Equivalent circuit models