Increase reading distance of CR95HF

[chris1911]

Currently, I'm using CR95HF on our product which went into mass production already.  The tag is small with diameter only 9mm.  In the field, we are seeing a few percentage of unsuccessful read from the first read and need to retry several times.  How can we increase reading distance?  Is it possible to boost the transmit power from the reader chip?

The tag has NTAG213 on it.  Our reader antenna is in octagon shape.

[chris1911]

Right now, we are using 3.3V for both VPS_Main and VPS_TX.  I'm think if we keep 3.3V for VPS_Main and use 5V for VPS_TX, we should get a higher RF power.  A higher RF power probably will increase the reading distance.  Do you think this will work?

[Peter BENSCH]

Welcome @chris1911, to the community!

You won't experience a significant change in range with this slightly higher voltage. You have a significantly greater influence on this with larger antenna geometries, both at the reader and the tag. Since the tag is apparently fixed, you can only try to achieve more range with a larger reader antenna.

What dimensions does the reader antenna currently have?

Regards
/Peter

[chris1911]

Hi Peter,

Thanks for your comment.  Below picture show our reader antenna size which is slightly larger than the Tag which is 9mm in diameter.  We have three readers in a row to check three tags but only one reader is enable at the same time.  The distance between the antenna and the tag is about 8mm.  Will we get better reading distance with a bigger antenna?  What size will you suggest us to try?

Regards,

Chris

[Peter BENSCH · Accepted solution]

Of course, it would be ideal if both the tag and reader antenna were significantly larger.

But even if the tag remains the same size, you will achieve slightly better results with a larger reader antenna. You can also test this without a new PCB by cutting off one of the PCB coils and connecting a wire coil with different diameters to the vias.

Regards
/Peter