CC1350: Help with trace impedance due to long trace distance from antenna on CC1350

Pushkar Merwah

Part Number: CC1350

Hi Group,

Our boards are thicker than the CC1350 Eval board and the traces from I/C to the matching network and/or to the antenna are long (up to 50mm) without any constraints on the trace impedance. We would like to know if you can offer any guidance on best practice for laying out these traces and the matching network?

In addition, can you provide help in verifying if the traces/environment along with the matching network that we have on our board is satisfactory for the wireless interface (some sort of a EM simulation)?

Thank you.

over 6 years ago

0 TA12012 over 6 years ago

TI__Mastermind 36375 points

Pushkar,

Here is a good tool, you can download it for free and it will help you calculate the correct dimensions.

www.awrcorp.com/.../tx-line-transmission-line-calculator

Regards,
/TA

0 Pushkar Merwah over 6 years ago in reply to TA12012

Prodigy 70 points

Hi TA,

Thanks for the link. We do have the tools to tune the trace impedance. Since our board thickness is different, the helical antenna may not be properly centered for 868MHz operation and the matching network and/or the physical properties of antenna might need to be modified. Original design has a board thickness of 0.8mm while our board is 2.2mm thick. Can you offer some guidance on how to go about it? If there are any formulas that we can use to fine tune the design or any electromagnetic simulations that you can help us with then that would be great.

For cross reference, there is a similar thread

e2e.ti.com/.../2150268

but we would like to have first pass success rather than trial and error.

Regards,

- Pushkar

0 Angel E over 6 years ago in reply to Pushkar Merwah

Prodigy 135 points

increasing the thickness will improve the antenna efficiency. You have to use VNA for finding the input impedance and smith chart for making matching circuit.

0 TA12012 over 6 years ago

TI__Mastermind 36375 points

Pushkar,

We will take this offline, I have asked a TI sales engineer to call you and provide you with my contact information.

Regards,
/TA

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CC1350: Help with trace impedance due to long trace distance from antenna on CC1350