SARA-N2 series - System Integration Manual
UBX-17005143 - R06
System description
Page 16 of 82
1.7
Antenna interface
1.7.1
Antenna RF interface (ANT)
The ANT pin of SARA-N2 series modules represents the RF input/output for the cellular RF signals
reception and transmission. The ANT pin has a nominal characteristic impedance of 50
and must
be connected to the antenna through a 50
transmission line for proper RF signals reception and
transmission.
1.7.1.1
Antenna RF interface requirements
summarizes the requirements for the antenna RF interface (ANT). See section
suggestions to properly design an antenna circuit compliant to these requirements.
⚠
The antenna circuit affects the RF compliance of the device integrating SARA-N2 series module
with applicable required certification schemes.
Item
Requirements
Remarks
Impedance
50
nominal characteristic impedance
The nominal characteristic impedance of the
antenna RF connection must match the ANT pin
50
impedance.
Frequency range See the SARA-N2 series Data Sheet
The required frequency range of the antenna
depends on the operating bands supported by the
cellular module.
Return Loss
S
11
< -10 dB (VSWR < 2:1) recommended
S
11
< -6 dB (VSWR < 3:1) acceptable
The Return loss or the S
11
, as the VSWR, refers to the
amount of reflected power, measuring how well the
RF antenna connection matches the 50
impedance.
The impedance of the antenna RF termination must
match as much as possible the 50
impedance of
the ANT pin over the operating frequency range,
reducing as much as possible the amount of
reflected power.
Efficiency
> -1.5 dB ( > 70%) recommended
> -3.0 dB ( > 50%) acceptable
The radiation efficiency is the ratio of the radiated
power to the power delivered to antenna input: the
efficiency is a measure of how well an antenna
receives or transmits.
The efficiency needs to be enough high over the
operating frequency range to comply with the Over-
The-Air radiated performance requirements, as
Total Radiated Power and Total Isotropic Sensitivity,
specified by certification schemes
Maximum Gain
See section
for maximum gain limits
The power gain of an antenna is the radiation
efficiency multiplied by the directivity: the maximum
gain describes how much power is transmitted in the
direction of peak radiation to that of an isotropic
source.
The maximum gain of the antenna connected to
ANT pin must not exceed the values stated in
section
to comply with regulatory agencies
radiation exposure limits.
Input power
> 0.5 W peak
The antenna connected to ANT pin must support the
maximum power transmitted by the modules.
Table 7: Summary of antenna RF interface (ANT) requirements
☞
For the additional specific requirements applicable to the integration of SARA-N211 modules in
devices intended for use in potentially explosive atmospheres, see section
