Wi-Fi&Bluetooth Module Series
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D1 shall be placed as close to the antenna as possible. The NM in the figure below is not attached by
default.
J1
ANT_WIFI0/BT
R1 0R
C1 NM
C2 NM
C3 NM
L1 NM
D1 NM
Figure 9: Reference Circuit for RF Antenna Interface
4.2. Reference Design of RF Routing
For user’s PCB, the characteristic impedance of all RF traces shall be controlled to 50 Ω. The impedance
of the RF tra
ces is usually determined by the trace width (W), the materials’ dielectric constant, the height
from the reference ground to the signal layer (H), and the spacing between RF traces and grounds (S).
Microstrip or coplanar waveguide is typically used in RF layout to control characteristic impedance. The
following are reference designs of microstrip or coplanar waveguide with different PCB structures.
Figure 10: Microstrip Design on a 2-layer PCB
