SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08
Objective Specification
System description
Page 38 of 188
1.7
Antenna interface
1.7.1
Antenna RF interface (ANT)
The
ANT
pin of SARA-G3 and SARA-U2 series modules represents the RF input/output for transmission and
reception of the 2G or 3G RF signals. The
ANT
pin has a nominal characteristic impedance of 50
and must be
connected to the antenna through a 50
transmission line to allow proper RF transmission and reception in
operating bands.
1.7.1.1
Antenna RF interface requirements
Table 10 summarizes the requirements for the antenna RF interface (
ANT
). See section 2.4.1 for suggestions to
properly design an antenna circuit compliant to these requirements.
The antenna circuit affects the RF compliance of the device integrating SARA-G3 and SARA-U2
series module with applicable required certification schemes. Compliance is guaranteed if the
antenna RF interface (ANT) requirements summarized in Table 10 are fulfilled.
Item
Requirements
Remarks
Impedance
50
nominal characteristic impedance
The impedance of the antenna RF connection must match
the 50
impedance of the
ANT
pin.
Frequency Range
See the
SARA-G3 series Data Sheet
[1] and the
SARA-U2 series Data Sheet
The required frequency range of the antenna depends on
the operating bands of the used modules.
V.S.W.R
Return Loss
< 2:1 recommended, < 3:1 acceptable
S
11
< -10 dB recommended, S
11
< -6 dB acceptable
The impedance of the antenna termination must match as
much as possible the 50
impedance of the
ANT
pin over
the operating frequency range.
Input Power
> 2 W peak
The antenna termination must withstand the maximum
peak of power transmitted by the modules during a GSM
single-slot call.
Gain
See section 4.2.2 for gain limits
The antenna gain must not exceed the herein specified
value to comply with FCC radiation exposure limits.
Detection
Application board with antenna detection circuit
If antenna detection is required by the custom application,
proper antenna detection circuit must be implemented on
the application board as described in section 2.4.2.
Antenna assembly with built-in diagnostic circuit
If antenna detection is required by the custom application,
the external antenna assembly must be provided with
proper diagnostic circuit as described in section 2.4.2.
Table 10: Summary of antenna RF interface (ANT) requirements
For the additional specific requirement for SARA-G350 ATEX modules integration in potentially explosive
atmospheres applications, see section 2.14.