Gnss Antenna Reference Circuit - Sunsea AIoT SIMCom SIM5800 Hardware Design

R1, C1 and C2 are antenna matching components in Figure 36, the value of these components are determined
according to the antenna tuning results. By default, R1 is 0Ω, C1 and C2 are reserved. The RF connector in Figure
36 is used to ensure the accuracy and convenience of the conduction testing, so SIMCOM suggest keeping it. If
considering Low-Cost BOM, user can cancel the connector.

4.19.2 GNSS Antenna reference circuit

The recommended circuit is shown as
ANT_GNSS
Module
R1, C1 and C2 are antenna matching components in Figure 37, the value of these components are determined
according to the antenna tuning results. By default, R1 is 0Ω, C1 and C2 are reserved. The RF connector in Figure
37 is used to ensure the accuracy and convenience of the conduction testing, so SIMCOM suggest keeping it. If
considering Low-Cost BOM, user can cancel the connector.
The module has internal LAN, so there is no need for external active antenna. But if the antenna is far away the
module and need a long cable to connect, users can use external active antenna, the recommended circuit is shown
Figure 38:
ANT_GNSS
Module
In Figure 38, the VDD is used to provide voltage to the external active antenna and its value should be taken
SIM5800_Hardware Design_V1.01
Smart Machine Smart Decision
Figure 36: MAIN antenna recommended circuit
:
Figure 37
RF connector
(optional)
GND
120
121
GND 122
Figure 37: GNSSantenna recommended circuit
RF connector
(optional)
GND
120
121
GND 122
Figure 38: GNSS active antenna circuit
Matching circuit
R1
C1 C2
C1
43
GNSS Passive
ANT
GNSS Active ANT
47nH
10ohm
VDD
2018-10-08