The FCC no longer accepts a “manufacturer’s declaration of gain” without any supporting justification.
At a minimum, each Part 15 application must include the antenna documentation described below as appropriate for each antenna approved for use with the device:
No Antenna: Justification statement that “all measurements were performed radiated and therefore additional antenna gain documentation is not required”, with clear photos of the antenna build and dimensions; additional information may be required
Sourced Antenna: Data sheet from antenna manufacturer with the following details is acceptable provided configuration does not alter parameters:
Manufacturer name and address
Antenna Model #
Max gain for frequency band of operation
Antenna patterns (2D or 3D)
Proprietary Antenna: Antenna Under Test (AUT) Report in accordance with stated guidelines (see below)
Reference Design: Antenna reference design specifications from original engineering application notes and close, detailed photos of the circuit board
These requirements apply to all Part 15 certifications granted after August 25, 2022. Please refer to the FCC Part 15 Antenna Update presentation to the Fall 2022 TCB Workshop for important, additional details for compliance with these requirements, including the list of the content that must be presented in an AUT Report required for proprietary antennas.
KDB 353028 D01 Antennas Part 15 Transmitters v01r01 provides basic rules and policy requirements of Parts 15.203 and 15.204 for antennas used with intentional radiators and a Q&A.