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I am in the process of designing a board that turns a Gameboy into a Bluetooth controller. Due to size constraints, I would like to use the ESP32-PICO-D4 standalone chip by Espressif instead of one of the larger modules that has an integrated PCB antenna like the ESP32-WROOM-32. In Espressif's dev kit for this chip, they use a 3D chip antenna as shown in this image of the board. here

This antenna is the PRO-OB-440 by ProAnt AB as shown on their page here and the Digi-Key product page here.

As I would like to eventually sell this product, I know that there are certification requirements that should be taken into consideration. After reading up on this through the FCC's Title 47 CFR Part 15 under Subpart C - Intentional Radiators as well as an article from EMC FastPass about pre-certified RF modules, I saw that they were wanting to cut down on the number of products that needed certification by encouraging the re-use of pre-certified modules.

If I was to use the same chip and antenna together, would this pre-certification for the dev kit carry over to my product?

Note: The dev kit's certification documents can be found here.

(Also, I feel that my question is different from this one as that board uses an integrated PCB antenna while my question focuses on an RF chip combined with a surface mount antenna.)

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    \$\begingroup\$ the ESP32-PICO-D4 that you linked is just a chip, not a module .... there is no antenna .... you would have to certify any product built with it ...... the ESP32-WROOM-32 is a module with a builtin antenna .... if it is certified, then it appears that you would not have to recertify your product \$\endgroup\$ – jsotola Jul 19 '18 at 1:01
  • \$\begingroup\$ Thanks for the critique. I have modified the question to use the correct terminology. \$\endgroup\$ – Kyle Jul 19 '18 at 1:12
  • \$\begingroup\$ I am aware that normally combining two products such as an RF chip and an antenna would require recertification, but I am planning to use the same two components from the dev kit that is already certified in my own design. Would this certification from such a product carry over to a new product seeing as it uses the same components? \$\endgroup\$ – Kyle Jul 19 '18 at 1:18
  • \$\begingroup\$ same difference .... the dev kit may be certified, but you are not using the dev kit in your device ... it is not just the components that you are certifying, but the board layout as well ... bad board layout could cause unintended radio emission \$\endgroup\$ – jsotola Jul 19 '18 at 1:19
  • \$\begingroup\$ Fair enough. That is unfortunate. I was hoping that it would be different in that case and would instead carry over. \$\endgroup\$ – Kyle Jul 19 '18 at 1:23
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Google "pre-certified chip" and you get a few dozen results, mostly for chip-and-pin payment. An RF chip is not so much pre-certified as tested by the manufacturer to verify that it is capable of meeting certification requirements when paired with the right antenna. A "pre-certified module" will usually have a shielding package that adds to the size, and that also reassures regulators by making it harder to modify the module after purchase. The same combination of chip and antenna could produce different results depending on connections, orientation, PCB parameters and routing, and if the agencies did not require such changes verified, no one would be selling the modules.

Yes, the module costs more and constrains your design. Below 10,000 units, it is still worthwhile, just to avoid months of delay and many thousands for testing. Any decent module is generally certified in multiple jurisdictions, giving you future flexibility, instead of needing a lab to test separately for each of those.

Many regulators have some form of Declaration of Conformity self-approval program; you are likely to need at least the paperwork for that even with a pre-certified module.

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  • \$\begingroup\$ Thank you for your answer. It helped me find some information that I had been missing before. Also, I found a statement saying that certain qualifications can be omitted "if the design is based on the same layout as a previous design as they can then be qualified by similarity" ( devzone.nordicsemi.com/f/nordic-q-a/21433/… ). Would this carry over to my design if I based it on the development kit layout previously mentioned? \$\endgroup\$ – Kyle Jul 20 '18 at 21:18
  • \$\begingroup\$ @Kyle You would need to ask someone who does chip-down RF certification. The option might only be available to the original certification holder, might demand an exact match (same source files, no substantial changes anywhere on the board), might still require you to supply the original certification's test results, might be up to an individual inspector's discretion... A lot has been written on similar subjects, like the FCC's "permissive changes" policy. \$\endgroup\$ – MBer Jul 20 '18 at 23:49
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    \$\begingroup\$ I see. I will try to work with one of the pre-certified modules then. If it fits, it will be a tight fit. I haven't found anything conclusive about the ESP32 having modular licensing, so it probably doesn't have it, but I might try to reach out to Espressif to verify this as a pre-certified chip-down solution would solve the space issue. At any rate, thank you for your time and answer. \$\endgroup\$ – Kyle Jul 21 '18 at 0:05

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