Rfid metal system

Discussion in 'Wireless & RF Design' started by andreaschar90, Aug 17, 2012.

  1. andreaschar90

    Thread Starter New Member

    Nov 8, 2011
    13
    0
    Hi there,

    I am trying to design and build a RFID system (tag and reader).
    The requirements are the following:
    1.The tag must be read by the reader up to a meter.
    2.The tag tag should be small about=11mmx11mmx11mm)
    3.The tag will be mounted on a metal

    In my opinion I will use low frequency (125khz) because the skin effect will be lower and the signal will not be so affected by the metal. Also, I was thinking to use ferrite between the metal and the tag to increase the read range.
    But I have a disadvantage by using low frequency. I cannot reach a meter.
    The components that I was thinking to use are: tag:TK5551, reader: u2270b, and I was thinking to amplify the magnetic field by adding an amplifier if that would be possible. by using those components the max read range that I could achieve is 10cm without amplifier or something else.

    If you have better ideas please help,any ideas would be acceptable and let me know how can I reach at least half meter by using a tag mounted on metal at what frequency and what tag and reader should I use please?

    I NEED HELP URGENTLY PLEASEE.
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    How big is the transmitter coil? If you increase its diameter you will be able to increase your distance.
     
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  3. geoffers

    Active Member

    Oct 25, 2010
    239
    6
    Hi,
    I've been playing around with RFID stuff for a while, I don't know about the effect of the metal, but you will get a better range using HDX transponders, have a look at the texas website. I'm using the U2270b and with a small glass transponder 3mm dia. The best range I have been able to get is about 10cm, (I'm working on it though!). The texas tms3705 is worth looking at for hdx reader ic.
    Good luck, Geoff
     
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  4. geoffers

    Active Member

    Oct 25, 2010
    239
    6
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  5. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    I have been working on an RFID Identification system using tags mounted on metal substrate, and I had have better luck using higher frequency (13.56 MHz) to achieve the longer distance read (up to 5 meters) with a passive tag..... unless you want to use an "active" tag, but then you will have to add extra circuitry to the tag and a power source.... unfortunately I can not disclose anymore than that (damn non disclosure agreements!)

    I have not seen or heard of any readers at that frequency that can do more than 10cm's unless you use an active tag.
     
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  6. andreaschar90

    Thread Starter New Member

    Nov 8, 2011
    13
    0
    Had you simulate the u2270b, before build it? do you know any spice model of u2270b?
     
  7. andreaschar90

    Thread Starter New Member

    Nov 8, 2011
    13
    0
    Can I add an amplifier on the output of the u2270b in order to increase the voltage->increase the reading distance?
     
  8. geoffers

    Active Member

    Oct 25, 2010
    239
    6
    Hi,
    I'm afraid I picked it up as I went along, also look at the em4095, I used that first, but its alot easier to get the u2270b in the UK. I havn't ever done any spice simulations so cant help you there. Do have a good read of the rfid coil design though, once you have got your coil design maximised, then look at upping the voltage. When youv'e done it let me know how you get on, I'm trying the same thing! I would say if you want maximum read distance with minimum hassle try the hdx stuff from texas, I'm stuck with the fdx as well as I need to read both.
    Good luck Geoff
     
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