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RI-TRP-DR2B: Question about orientation in 134.2 kHz transponders.

Part Number: RI-TRP-DR2B
Other Parts Discussed in Thread: MRD2EVM

Hi,

I have been working with S2000 (Low Frequency) RFID readers in several applications. One of the limitations is no multitag reading. However, why are no transponders developed with several coils oriented perpendicularly?

Since the 'readout diagram' of the transponder depends on the orientation of the transponder with respect to the reader antenna. I would like to know/build a transponder with several coils to avoid this orientation dependency. I know I could use differente configurations for the antenna readers, but that is not a possible solution for me.

I am somehow surprised that there are no transponder built with this feature . I put as example the transponder https://www.ti.com/product/RI-TRP-DR2B .

I have the following questions:

1- Is there anything I am missing or reason why tags with differents antennas are not developed?

2- Given the fact it seems TI does not manufacture 134 kHz transponders with several antennas embedded, is there any manufacturer or any starting point to build it on my own?

Regards,

  • Hello MRR,

    I think the main reasons for one antenna encapsulated transponders might be form-factor, IC complexity and cost. But for more complex applications TI is also offering a 3D antenna IC, which is the RF430F5978. Let me know if you have further questions.

    Best regards,

    Andreas.

  • Dear Andreas,

    Thank you for your answer. I have been researching for more information about the transponders with no success. I have the following questions I'd like to ask:

    - Is there any more information about any of the transponders compatible with the series 2000 readers? (134.2 kHz). I have thought about opening one of the tags and trying to build a second antenna perpendicularly oriented. Is there any information or other manufacturer that builds transponders compatible?

    - Regarding the RF430F5978, is it compatible with the series 2000 readers (specifically we have one of this readers ). I found this evaluation kit: www.ti.com/.../RF430F5978EVM.

    For us, it is critical tag orientation or multi-tag detection. Any further information provided is useful for me.

    Best regards,

    -MRR

  • Hello MRR,

    sorry for the late reply, but it took me some time to research the options. Since every setup is very use case specific, I would like to ask for your use case. Also is it a single device project or a bigger quantity application (which might require more standardized or low cost parts). Which exact control module and RFM are you using in your reader?

    Best regards,

    Andreas.

  • Dear Andreas,

    Thank you for your reply.

    I am working with the reader RI-CTL-MB2A and the Series 2000 Standard RFM (RI-RFM-104B). Reference documents:

    • 11-06-21-035 October 2002. Series 2000 Reader System Standard Radio Frequency Module R-RFM-104B.
    • 11-06-21-037 January 2000. Series 2000 Reader System, Control Modules RI-CTL-MB2A, RI-CTL-MB6A.

    These are the modules that came in the Series 2000 Low Frequency RFID Evaluation Kit. Part number: RI-K2A-001A.

    In addition, we also have the Series 2000 High Performance RFM (RI-RFM-007B) and the reader RI-CTL-MB2B-30, but so far we are using the aforementioned modules. Once the tests are carried out probably I will consider RI-RFM-007B with RI-CTL-MB2B-30 (www.ti.com/.../scbu044.pdf) just to check if there are substantial differences in performance.

    Regarding the use case, currently it is a single device project but we have funding to extend it depending on the tests I am carrying out. Mainly we are trying to build specific antenna geometries and hold the distance tag detection as uniform as possible from then. The antennas are built close to metals (the main reason we consider low inductive coupling). Let me summarize the main problems we are facing:

    • Multi tag detection. The main problem here is that, when there is more than one tag emitting with similar power, there are situations where the reader RI-CTL-MB2A does not detect any transponder. For our purpose, it would be enough to detect just one tag when there is more than one inside the reading zone. Is there any possibility to solve this problem (maybe have the capacity to modify the reader firmware).

     

    • Orientation dependency. As far as I know, Texas Instruments does not provide transponders with this question in mind (3D antenna loops built-in in the tag, etc.). I am looking for any information available to modify the TI transponders compatible with Series 2000, or any other option.

    Finally, I know there are other possible technologies candidates for these purposes, but inductive coupling and passive transponders is one of the restrictions.

    If you need more information please let me know.

    Best regards,

  • Hello MRR,

    regarding multi tag detection: Typically this issue is addressed by anti collision algorithm implemented in the reader firmware. I'm not sure if the Series 2000 reader supports it. Please understand that TI can not support any reader firmware modification of that 20 years old reader hardware. You would have to do it on your own.

    Regarding the transponder orientation issue: TI is not offering any complete 3D transponder. If you modify the single antenna transponder, then this might be a tricky surgery as it is encapsulated in glass or plastic. If you plan to split the antenna for 3 dimensions, then you will lose read range. Transponders with 3 antenna inputs would be the best solution but the RF430F5978 might be overdone for this purpose, as it also includes an UHF interface. Actually the LF is mainly used to wake up the device from low power standby and then the main communication is done via UHF. Although it would be possible to communicate also via LF, I'm not sure if this is compatible to the Series 2000 reader. You could give it a trial or evaluate the MRD2EVM, which comes with the RF430F5978EVM.

    Let me know if you have further questions.

    Best regards,

    Andreas.

  • Hello Andreas,

    I could not find any information related with the possible firmware modification of the reader; anti-collision algorithms are not implemented in the Series 2000 readers. I guess this information is not public. In any case, I want to thank you for you valuable comments, probably I will give a try to the MRD2EVM.

    Best regards,

    MRR

  • Hello MRR,

    thanks for the feedback. Have fun with the MRD2EVM. I will close this thread for now. Feel free to reach out again if needed.

    Best regards,

    Andreas.