Hello! I am working on a project that uses UHF RFID and passive tags to record accurate distance of the passive tag in relation to the reader. I was trying to find if it is possible to get (ultimately) the phase difference between the TX and RX RFID signal. I can just use the RSSI strength, which I will. But for my purposes I really need the phase difference of the two signals. Let me know if this is possible and if not, if anyone has other ideas of sub $300 options for readers in UHF…
Never understood /bordered about “phase” in the tag response, but maybe it is your answer.
As part of the tag-data there is a “tag phase”, according to the M6E datasheet:
Tag Phase: Average phase of tag response in degrees (0°-180°)
Why not 0 - 360 is explained on https://www.jadaktech.com/wp-content/uploads/2022/08/ThingMagic-General-FAQs-02282020-1.pdf
Someone had a question about his before “Phase Ambiguity of UHF RFID - Stack Overflow”
In order to obtain the tag-phase information there are 2 options.
- int8_t phase = nano.msg[22].
- Having extended the Sparkfun library with many other calls and options, I have also updated the version with a getTagPhase() call and added example22 to demonstrate. My version can be found on ThingMagic/Arduino_lib_special at master · paulvha/ThingMagic · GitHub.
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