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5G Module Series
RM505Q-AE Hardware Design
RM505Q-AE_Hardware_Design 55 / 79
5.5. Reference Design for Cellular Antenna Interfaces
A reference design for cellular antenna interface is shown as below. A π-type matching circuit should be
reserved for better cellular RF performance. The capacitors are not mounted by default.
R1
C1 C2
R4
C7 C8
C9
C10
R5
ANT0
ANT3
ANT4_GNSS
0R
0R
0R
Figure 29: Reference Design for Cellular Antenna
1. Keep the characteristic impedance for cellular antenna traces to 50 Ω.
2. Place the π-type matching components as close to the antenna as possible.
3. Keep the digital circuits, such as that of (U)SIM card, USB interface, camera module, display
connector and SD card, away from the antenna traces.
4. Keep 75 dB PCB isolation between two antenna traces.
5. Keep 15 dB isolation between each two antennas to improve the receiving sensitivity, and 20 dB
isolation between 5G NR UL MIMO antennas.
NOTES