RF37S114: RFID range

Hello Zan,

You won't get 20mm with the RF37S114. The tag is too small to provide such range. Antennas large enough to produce enough power would not be able to couple with the tag due to a large difference in the coil sizes. We did an app note that shows when you get diminishing returns from coil size actually: www.ti.com/.../scba035a.pdf

In the setup you are describing, you would need credit card sized ISO15693 tags. With that, you may be able to get 20mm. But keep in mind that with an antenna that large, 200mW of power from a reader will leave you with read holes in the middle as it isn't possible to output a large enough H-field with that level of power to blanket the whole antenna area.

Regarding your other questions in general for ISO15693 (since the RF37S114 won't work for your application)

2) HF RFID is all based on H-field coupling, so ideally you don't want to have the tag perpendicular to the antenna. With large gate antennas, that usually isn't as much of a problem because of the amount of H-Field lines you have, but you may find read holes exist if the tag is perpendicular.

3) Environmental changes like that can affect tags a bit, though as far as years go, I wouldn't be worried about degrading over time as long as the tag casing is made out of good materials and that really is a material question at that point. From a technology standpoint, the read range may reduce a bit with humidity, but it shouldn't be a massive effect.

Hello Zan,

Yeah we don't have any other fully integrated tags of that size. There are also the 2cm diameter overmoulded laundry transponders that we offer, but that's about it. Even those laundry transponders would be hard to hit the ranges you want though. Anything else that is in an inlay form factor would come from third parties, we have a few that make tags similar to the inlays we used to sell such as SAG and Smartrac.

While the Murata tag may have specs for higher ranges, I don't foresee them being able to do what you are looking to achieve either with such a small form factor and such large antennas. But feel free to experiment with their tags as well, you certainly can read them with TI reader/writer devices.

As far as our portfolio for reader device, the 200mW is the highest output device we have. Some customers use power amplifiers to increase the output power further which would be good for your application. However, we do not provide any support for power amplifier applications at this point. ...Though if you use the search future for our E2E forums... you may happen to find a design or two that were offered in the past... there's one from 2013 which I've heard is pretty good... You didn't hear that from me though ;)

Ill sort something out.
Thank you very much for you help!