MRD2EVM: Power burst and source code

Hello Imantha,

Before I answer your question, please help me with some context, what is the current read range performance you are getting and what read range performance are you seeking to achieve?

Hi Ralph,

I'm currently getting ~8cm read range with the TRPGR30ATGC 12mm transponders in a perpendicular orientation (which appears to be the preferred orientation).
This was in initial testing on my desk but in the real application there will be metal and rubber in close proximity to the antenna and so I believe the read range will go down.

I know a larger antenna will give a greater read range but I want to see what the maximum read range I can get with the system as is, before I go on to design an antenna.

My understanding is that the antenna first charges up the transponders and then the transponders transmit back. I expect the power of this return transmission will depend on how charged up the transponder is. Since the application is not time sensitive, I want to see if this return transmission power and hence the read range can be increased by increasing the charging up time (which I believe is what the burst time refers to?).

The aim for this application is to get as much read range as is possible for the transponder and so we would like to get as close as possible to the transponders maximum read range of 60cm.

Thanks,
Imantha

Hello Imantha,

Thank you for those details. I can say for sure that you won't get 60cm as the MRD2EVM doesn't have that kind of power output, but I have passed your query about extending the 8cm read range via software adjustments to the product team and am awaiting their feedback on what options are available on that front.

Hello Imantha,

Here is the feedback I received:

It is difficult to extend the read range of the MRD2.

Maybe a larger antenna and a longer charge pulse give a small improvement, but the main problem will be the weak return signal of the 12mm transponder and the not very high sensitivity of the readers receiver.

Regarding the impact of a larger antenna, we have tested that you can achieve 10cm with the 12mm transponder in the ideal orientation.

A test has been done with an antenna around 6cm * 12cm and in ideal orientation the 10cm range was reached. However if the orientation of the transponder being parallel to the antenna it will be difficult to achieve the 10cm with the micro-reader.

Hi Ralph,

Thanks for that response. It's good to know that I won't get much above 10cm even with a bigger antenna.

Do you have another reader that will be able to achieve a greater range? In particular I noted that the datasheet for the transponder states the typical read range as being <= 60cm and it would be good to know what this value is based on.

We are willing to switch to the larger 32mm or 23mm transponders but my tests suggest we won't get much above 20cm on the MRD2, even with these transponders.

Thanks,
Imantha