To maintain modular approval in the United States, only the antenna types that have been tested shall be used. It is permissible to use different antenna provided the same antenna type and antenna gain (equal to or less than) is used. An antenna type comprises antennas having similar in-band and out-of-band radiation patterns.
For the ATWINC15x0-MR210PB, the approval is received using the integral PCB antenna.
For the ATWINC15x0-MR210UB, approved antennas are listed in the Recommended External Antenna for ATWINC15x0-MR210UB.