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FIBOCOM NL668-LA Series Hardware Guide
Page 49 of 61
Figure 7-1 Main and diversity antenna reference circuit
Figure 7-2 is reference design of GNSS antenna.
Figure 7-2 GNSS antenna reference circuit
Note
:
All matches must be placed close to antenna to make sure the characteristic impedance of
transmission cable is 50 ohms.
Since the antenna loss should be less than 0.3dB, keep PCB cable as short as possible.
Keep the PCB LAYOUT straight, and reduce holes on the route to another layer; also avoid
right-angle and acute-angle wiring.
PCB cable should have a good reference ground to avoid other signal cable near the antenna.
Recommend a complete ground level, and use this complete ground level as a reference
ground.
Ground around antenna must be keep connect with main ground.
For more design information please refer to
FIBOCOM Design Guide_Antenna.