CC1200: 868Mhz helix antenna modification

Francisco Fernandez

Part Number: CC1200

Hi.

I attach a proposition of a 868mhz antenna based on your DN038. As you can see my design is forced to modify the long feed track of the antenna because it is impossible for me to move the antenna feed point to the left.d

How much would it affect the antenna performance? Would still be possible to tune it with inductor/capacitors at the feed point? The original design has a distance of 6mm between antena tracks and ground but my design has a distance between antenna tracks and ground of 3.9mm.

Thanks

5 months ago

0 Haiatullah Gholami 5 months ago

TI__Expert 3050 points

Hi Francisco,

You can use the modified antenna. It will have a different resonance frequency than our reference design, but you can use the pi matching network to tune the antenna.

Regards,

0 Francisco Fernandez 5 months ago in reply to Haiatullah Gholami

Prodigy 70 points

Does the resonance frequency change more due to the not straight feed point or due to the shorter distance to GND?

Do you offer the tunning service?

We have never tunned an antenna. What tooling would we need? A VNA?

Do you have any documentation related to antenna tunning?

Thanks

+1 Haiatullah Gholami 5 months ago in reply to Francisco Fernandez

TI__Expert 3050 points

Hi Francisco,

The change in the resonance frequency can be caused both because of the change in the antenna trace and the distance to the GND. Even the packaging of the board will affect the resonance frequency on an antenna due to change in the impedance. That is why we always recommend our customers to have a pi matching network on their design.

For information on how an antenna matching can be performed, see https://www.ti.com/lit/an/swra726/swra726.pdf?.

Regards,

Sub-1 GHz

Sub-1 GHz forum

CC1200: 868Mhz helix antenna modification