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PCB Antenna for Tags

9 months ago

PCB Antenna for Tags

Posted bysr92130 points 4 replies
0 upvotes

Dear Dialog Team,

We are trying to leverage the antenna used in the DA14580_RD_WLCSP_SMTAG2_vC design for our Tags based on DA14585, but we have few queries:

1) Why is there a trace at the bottom layer of the antenna too and why are there vias connecting the top and bottom traces of the antenna? Don't PCB antennas have a trace on a single layer?

2) Can we remove the bottom trace of the antenna? Will it affect the antenna performance if we do so?

3) We have also gone through the AN-B-027 App Note that has a similar antenna like that of the smart tag, but in the app note, it is mentioned that "The dimensions above are given for a typical FR1 PCB substrate, 1 mm thick. The antenna length is adjusted for resonance, including a 1 mm plastic enclosure placed in contact with the PCB antenna". So we can't use the antenna with FR4 substrate, is my understanding correct? If we are to use what should be the thickness of the PCB and FR4 substrate? Can we achieve a total PCB thickness of 1mm with theSingle Layer Printed IFA, 1 mm Substrateantenna design?

Best Regards,

sr9213

9 months ago

PM_Dialog

Hi sr9213

The smart tag is an obsolete reference application design and isn't certified, so you cannot leverage this. A quite similar antenna is described in AN-B-027 document. Please check for the Single layer printed IFA, which has similar gain with the antenna on the smart tag. You could also find the dxf files in this link :AN-B-027: Designing Printed Antennas: DXF files

Regarding your last question, could you please clarify it?

Thanks, PM_Dialog

9 months ago

sr9213 0 points

Dear Dialog Team,

Thanks for your reply. We have already checked out the AN-B-027 document, but it was mentioned that the antenna is designed for a 1mm FR1 substrate. Will the antenna performance decrease if we use a FR4 substrate and what should be the thickness of the substrate? Can we achieve a 1mm total PCB thickness with this antenna? Will it have implications on the antenna performance?

Best Regards,

sr9213

9 months ago

PM_Dialog

Hi sr9213,

I have escalated your questions internally, so I’ll get back to you shortly.

Thanks, PM_Dialog

9 months ago

PM_Dialog

Hi sr9213,

Just got the following answers from the team internally – please take a look :

Q1] Will the antenna performance decrease if we use a FR4 substrate and what should be the thickness of the substrate?

A1] A FR4 substrate has a more stable relative permittivity and is better for antenna design.

Q2] Can we achieve a 1mm total PCB thickness with this antenna?

A2] Yes, the matching network of the antenna given in AN-B-027 might be changed. I would suggest to match the antenna with the help of an network analyzer, when the casing and PCB are ready.

Q3] Will it have implications on the antenna performance?

A3] A comparable performance should be achievable with the correct matching.

Thanks, PM_Dialog