Ublox TOBY-L2 series, Руководство по системной интеграции

Страница: 36 / 164

TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R28 System description Page 36 of 164
1.7.1.1 Antenna RF interfaces requirements
Table 8 , Table 9 and Table 10 summarize the requirements for the antennas RF interfaces
(ANT1 / ANT2). See section 2.4.1 for suggestions to properly design antennas circuits compliant with
these requirements.
⚠
The antenna circuits affect the RF compliance of the device integrating TOBY-L2 and MPCI-L2
series modules with applicable required certification schemes (for more details see section
4 ).
Compliance is guaranteed if the antenna RF interfaces (ANT1 / ANT2) requirements summarized
in
Table 8 , Table 9 and Table 10 are fulfilled.
Item Requirement Remark
Impedance
50  nominal characteristic impedance
The impedance of the antenna RF connection must
match the 50

impedance of the ANT1 port.
Frequency Range See the TOBY-L2 series Data Sheet [1] and the
MPCI-L2 series Data Sheet [2]
The required frequency range of the antenna
connected to ANT1 port depends on the operating
bands of the used cellular module and the used
mobile network.
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
primary antenna RF connection matches the 50

characteristic impedance of the ANT1 port.
The impedance of the antenna termination must
match as much as possible the 50
 nominal
impedance of the ANT1 port 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 radiation efficiency of the antenna connected to
the ANT1 port needs to be enough high over the
operating frequency range to comply with the
Over-The-Air (OTA) radiated performance
requirements, as Total Radiated Power (TRP) and the
Total Isotropic Sensitivity (TIS), specified by
applicable related certification schemes.
Maximum Gain According to radiation exposure limits The power gain of an antenna is the radiation
efficiency multiplied by the directivity: the 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
ANT1 port must not exceed the herein stated value to
comply with regulatory agencies radiation exposure
limits.
For additional info see sections
4.2.2 and/or 4.3.1
Input Power > 33 dBm ( > 2 W ) The antenna connected to the ANT1 port must
support with adequate margin the maximum power
transmitted by the modules.
Table 8: Summary of primary Tx/Rx antenna RF interface (ANT1) requirements