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TRF7962A antenna size for 1-1.5m RFID read range

Srikanth R
Expert 2650 points
Other Parts Discussed in Thread: TRF7962A

Hi,

ISO/IEC 15693 stipulates read ranges upto 1-1.5m. What is the antenna size I should use with TRF7962A for achieving this read range?

  • 0
    TI__Guru* 90906 points

    EMC regulations and physics of magnetic fields at the operating frequency govern the range  - the ISO standard makes no comment on distance. 

    to get the distance, an antenna in the neighborhood of something larger than 800mm x 600mm could be used with large rectangle tag like our RI-I02-112 product

    but, the 200mW max that the TRF79xxA devices put out is not enough power to drive that distance. an amplifier would be needed, and in the range of 4-8W output

    power with a suitable receiver for this kind of power out. Good example of a readers and antennas like this comes from Feig Electronics. 

     

  • 0 in reply to Josh Wyatt
    Expert 2650 points

    Hi,

    Many manufacturers are claiming upto 1.5m read range for their ISO 15693 tags. Some examples are as follows:

    http://www.st.com/web/en/home/catalog/mmc/FM76/CL1766/SC1204

    http://www.adafruit.com/datasheets/rfid%20guide.pdf

    In the above links read distance of various types of RFID tags is compared. Is that read distance with the same reader antenna?

    Also, if the reader antenna size is too big in the order 800mm x 600mm, then won't it be able to read any HF tag other than ISO 15693? Then what is the point in quoting higher read distances for some tags?

  • 0 in reply to Srikanth R
    TI__Guru* 90906 points
    the reality is that you can get into that read range with any ISO15693 system as i described in first reply. (large rectangle tag, large reader antenna, high power reader) - they just don't explain that - most likely its marketing - its catchy to say 1.5m read distance (it grabbed your attention, right?) - but then its not quite right, as that distance will only be seen with the large tag parallel to the reader antenna, in the center of the read zone - it will not be in all positions you might assume at first glance if you don't know or remember basic magnetics.

    the off the shelf readers that do this power out with large antennas (some going up to 1400mm x 800mm) will be ISO15693 (it is the vicinity RFID technology)

    ISO14443A and B and FeliCa are the proximity RFID technologies.

    Primarily you would not be able to read the proximity technologies at a long range because of several factors, but the main ones would be limitations on the reception of the subcarrier response at the data rate(s) of the reader - the Q factor limitation placed on the reader antenna because of the data rates, the general power out from proximity readers and the power consumption of the tags themselves.

    its the way its done - vicinity is used for longer range HF RFID == ISO15693, proximity is use for short range HF RFID == ISO1443A, B and FeliCa.

    hope that helps
    thanks