NFC RF Measurements chart | NFC RF measurements test setup

This page describes NFC RF measurements chart. It also mentions test setup used for NFC RF measurements. It mentions RF measurements of NFC device in polling mode and listening mode.

NFC stands for Near Field Communication. It works on the principle of inductive coupling. It is similar to working of the transformer device. The NFC device operates in two modes viz. polling mode and listening mode. The coil or loop antenna is in the form of rectangular or circular shape.

The NFC operating frequency is 13.56 MHz and it supports max. data rate of about 424 kbps. Both NFC polling device and listening device operates within a distance of about 10 cm. They both operates in different modes viz. card emulation mode, peer to peer mode and reader/writer mode. Refer NFC basic tutorial>>.

NFC devices support one or combination of standards which include NFC-A, NFC-B and NFC-F. The table mentions different modulation schemes, coding rates and data rates supported in these different NFC standards.

NFC standards
Table-1: NFC standards

ASK with 10% and 100% modulation and BPSK modulation types are used here. ASK modulation is also known as load modulation. Refer difference between 10 ASK vs 100 ASK modulation. Following RF measurements are performed when NFC device operates in listening mode and polling mode. The table-2 and table-3 mentions the common NFC test cases. NFC uses various coding techniques such as modified miller, manchester and NRZ-L. These different coding techniques depend on NFC forum standards i.e. NFC-A, NFC-B or NFC-F.

NFC RF Measurements Description
Carrier frequency accuracy This test will make sure that NFC carrier frequency is not deviating more than desired.
Power level This test will make sure that sufficient power is used in transmit mode (i.e. polling mode). Refer RF measurements tutorial>>.
NFC waveform This test will make sure that NFC timing waveform or diagram will meet the rise time, fall time as per mask defined in the standard.
Load modulation sensitivity This test will make sure that DUT in polling mode receives load modulation with min. specified level.
Threshold level This test will make sure that NFC DUT in polling mode switches off RF when it is exposed with external RF of certain field strength.

Table:2 NFC RF Measurements in active polling mode

NFC RF Measurements Description
Load Modulation The load modulation signal strength should be within limit when DUT operates in listening mode.
Power reception The DUT in listening mode will reply properly even in noisy environment. This will ascertain that power reception is proper even in bad conditions.
Frame delay time This test is done when the smartphone is in card emulation mode. It is the time duration from end of polling command till start of the transmission.

Table:3 NFC RF Measurements in passive listening mode

NFC RF Measurements Test Setup-1 Polling mode

NFC RF measurements require reference polling device and reference listening device. The reference polling device is used to test NFC DUT in the listening mode. The reference listening device is used to test NFC DUT in the polling mode.

The test setup uses following NFC equipments and software applications in order to perform RF measurements and baseband measurements to validate the NFC DUT.
• VSG (Vector Signal Generator): It is used to generate polling commands and listener responses.
• VSA (Vector Signal Analyzer) or RF Spectrum Analyzer: It is used to analyze or measure waveforms from the NFC DUT.
• Oscilloscope: It is used to verify the NFC timing waveform against defined mask. This will validate rise time, fall time and other timing parameters of the NFC waveform.
• There are various baseband applications developed to provide NFC waveform creation and analysis functionalities as per the NFC standards (A, B and F).

NFC test setup1 active polling mode

The figure-1 above depicts NFC test setup used to test the NFC DUT in the passive listening mode.

NFC RF Measurements Test Setup-2 Listening mode

NFC test setup2 passive listening mode

The figure-2 above depicts NFC test setup used to test the NFC DUT in the active polling mode. Rohde and Schwarz offers complete solutions for NFC RF measurements. R&S offers following test equipments and softwares for NFC testing.
• R&S® SMBV100A VSG (Vector Signal Generator)
• R&S® RTO digital oscilloscope
• R&S® FS-K112PC NFC measurement application softwares
• R&S® ZVL VNA (Vector Network Analyzer)
Also refer other NFC test tools and equipment vendors>>.

NFC technology related links

How NFC Works   NFC Modulation and coding   NFC basics    NFC-A,NFC-B,NFC-F types    NFC vs RFID    difference between bluetooth,wifi,RFID and NFC    What is NFC on phone    Difference between NFC tag types    NFC Tag vs NFC Reader   

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