User's Manual

SIM800 Document
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GND
Module
RF_ANT
GND
R101
C101
C102
RF Connector
GSM
Antenna
Figure1: GSM antenna matching circuit
R101，C101，C102 are the matching circuit, the value should be defined by the antenna design. normally R101
is 0Ω, C101 和 C102 are not SMD. The RF connector is used for conducted
5.2 Bluetooth antenna interface
The module provides a Bluetooth antenna interface named BT_ANT.
The external antenna must be matched properly to achieve best performance, so the matching circuit is
necessary, the connection is recommended as following figure:
GND
Module
BT_ANT
GND
R201
C201
C202
BT
Antenna
Figure 5: BT antenna matching circuit
R201，C201，C202 are the matching circuit, the value should be defined by the antenna design. R201 is
recommended as 1.2NH and C202 is 1.5pF, C201 are not SMD.
There are some suggestions to components placing and lying for GSM and Bluetooth RF traces:
 The RF connector is used for conducted test, so keep it as close as pin RF_ANT;
 Antenna matching circuit should be closed to the antenna;
 Keep the RF traces as 50Ω；
 The RF traces should be kept far away from the high frequency signals and strong disturbing source.