13.3 ATWILC3000-MR110UA Placement and Routing Guidelines

The ATWILC3000-MR110UA module has a micro co-ax (u.FL) RF connector for the external antenna. The choice of antenna is limited to the antenna types for which the module was tested and approved.

An approved list of external antennas tested and certified with ATWILC3000-MR110UA module is shown in Table 13-2.

It is critical to follow the recommendations listed below to achieve the best RF performance:
  1. Avoid routing any traces on the top layer of the host board, which is directly below the module area.
  2. Place the GND polygon pour below the complete module area. Do not have any breaks in this GND plane.
  3. Place sufficient GND vias in the GND polygon pour below the module area for better RF performance.
  4. Having a 5x5 grid of GND vias solidly connecting the exposed GND paddle of the module to the inner layer ground plane of the host board is recommended. This will act as a good ground and thermal conduction path for the ATWILC3000-MR110UA module. The GND vias must have a minimum via hole size of 0.2 mm.
  5. Keep large metal objects away from external antenna to avoid electromagnetic field blocking.
  6. Do not enclose the external antenna within a metal shield.
  7. Keep any components that may radiate noise or signals within the 2.4 GHz – 2.5 GHz frequency band away from the external antenna and, if possible, shield those components. Any noise radiated from the host board in this frequency band will degrade the sensitivity of the module.
  8. Make sure the width of the traces routed to GND, VDDIO and VBAT rails are sufficiently larger for handling the peak TX current consumption.
  9. Depending on the location of the antenna; the antenna must be placed at a distance greater than 5 cm away from the module.