Users Manual

RF-BM-BG22A3(I)
www.szrfstar.com V1.3 - Aug., 2022
Shenzhen RF-star Technology Co., Ltd. Page 16 of 26
5.4 Antenna
5.4.1 Antenna Design Recommendation
1. The antenna installation structure has a great influence on the module performance. It is necessary to ensure the
antenna is exposed and preferably vertically upward. When the module is installed inside of the case, a high-quality
antenna extension wire can be used to extend the antenna to the outside of the case.
2. The antenna must not be installed inside the metal case, which will cause the transmission distance to be greatly
weakened.
3. The recommendation of antenna layout.
The inverted-F antenna position on PCB is free-space electromagnetic radiation. The location and layout of the
antenna are key factors to increase the data rate and transmission range.
Therefore, the layout of the module antenna location and routing is recommended as follows:
（1） Place the antenna on the edge (corner) of the PCB.
（2） Make sure that there is no signal line or copper foil in each layer below the antenna.
（3） It is best to hollow out the antenna position in the following figure to ensure that the S11 of the module is
minimally affected.
Figure 7. Recommendation of Antenna Layout
Note: The hollow-out position is based on the antenna used.
5.4.2 Antenna Output Mode Modification
1. RF-BM-BG22A3 has two antenna output modes. The one is an onboard PCB antenna and the other is a stamp half-
hole output (ANT pin, see pin function table for details).