RF-BM-BG22A3(I)
Shenzhen RF-star Technology Co., Ltd.
Page 17 of 26
The default delivery is the
onboard PCB antenna
, and R1 (0 Ω) is well welded. If you want to use the external
antenna by the ANT pin, pls disconnect the R1. The location of R1 is shown in the figure below.
Figure 8. Antenna Output Mode Change of RF-BM-BG22A1
2. RF-BM-BG22A3I has two antenna output modes. The one is an IPEX connector and the other is a stamp half-hole
output (ANT pin, see pin function table for details).
The default delivery is the
IPEX connector
, and the capacitor connected to the IPEX is welded. If you want to use
the external antenna by the ANT pin, the capacitor position should be removed to the left solder joint to have the access
to the ANT pin. The location of the capacitor is shown in the figure below.
Figure 9. Antenna Output Mode Change of RF-BM-BG22A1I
5.4.3 External Antenna Design Recommendation of the Half-Hole ANT Pin
1.
A Π-type matching circuit is reserved for the antenna, and 50 Ω impedance control is performed on the RF traces.
The traces are as short as possible, and 135° or arc traces are used as much as possible. No vias are used to
change layers. More GND vias are placed around the RF traces.
Figure 10. Reference Design of the External Antenna