Data Sheet

6.2 Layout recommendations
6.2.1 STM32WB5MMG placement
The embedded antenna manufacturer of the STM32WB5MMG recommends to place the module on the
application board as shown below.
Figure 4. STM32WB5MMG board placement
This position allows the antenna to work to its maximum performance. If it cannot be placed as recommended
above, the application board performance is be reduced. This does not, however, prevent correct operation.
6.2.2 Enclosure effects
Product casing properties must be also considered when designing an RF-enabled product as the following
generic best practices list illustrated:
• Conductive enclosure in the near field affects the impedance of the antenna, also the resonant frequency.
A metal case must not be in the near field. The threshold between near and far-field is provided in Figure 5.
• Plastic enclosures can be close to the antenna, but must not touch it. Contact between the casing and the
antenna may influence the tuning of the resonant frequency and impedance matching.
• The proximity of the human body attenuates the TX and RX signals due to a certain amount of water
content. Any contact may untune frequency and impedance matching.
Figure 5. Conductive enclosure around the antenna
STM32WB5MMG
Layout recommendations
DS13252 - Rev 3
page 11/41