TOBY-L1 and MPCI-L1 series - System Integration Manual
UBX-13001482 - R04
Advance Information
System description
Page 31 of 90
Item
Requirements
Remarks
Impedance
50
Ω
nominal characteristic impedance
The impedance of the antenna RF connection must
match the 50
Ω
impedance of the
ANT2
pin / connector.
Frequency Range
•
746…756 MHz (Rx)
•
2110...2155 MHz (Rx)
The required frequency range of the antennas connected
to
ANT2
pin / connector depends on the operating
bands of the TOBY-L1 / MPCI-L1 module and the 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
secondary antenna RF connection matches the 50
Ω
characteristic impedance of the
ANT2
pin / connector.
The impedance of the antenna termination must match
as much as possible the 50
Ω
nominal impedance of the
ANT2
pin / connector 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
ANT2
pin / connector needs to be enough high over the
operating frequency range to comply with the Over-The-
Air (OTA) radiated performance requirements, as the TIS,
specified by applicable related certification schemes.
Table 9: Summary of secondary Rx antenna RF interface (ANT2) requirements
Item
Requirements
Remarks
Efficiency imbalance
< 0.5 dB recommended
< 1.0 dB acceptable
The radiation efficiency imbalance is the ratio of the
primary (
ANT1
) antenna efficiency to the secondary
(
ANT2
) antenna efficiency: the efficiency imbalance is a
measure of how much better an antenna receives or
transmits compared to the other antenna.
The radiation efficiency of the secondary antenna needs
to be roughly the same of the radiation efficiency of the
primary antenna for good RF performance.
Envelope Correlation
Coefficient
< 0.4 recommended
< 0.5 acceptable
The Envelope Correlation Coefficient (ECC) between the
primary (
ANT1
) and the secondary (
ANT2
) antenna is an
indicator of 3D radiation pattern similarity between the
two antennas: low ECC results from antenna patterns
with radiation lobes in different directions.
The ECC between primary and secondary antenna needs
to be enough low to comply with radiated performance
requirements specified by related certification schemes.
Isolation
> 15 dB recommended
> 10 dB acceptable
The antenna to antenna isolation is the loss between the
primary (
ANT1
) and the secondary (
ANT2
) antenna: high
isolation results from low coupled antennas.
The isolation between primary and secondary antenna
needs to be high for good RF performance.
Table 10: Summary of primary (ANT1) and secondary (ANT2) antennas relationship requirements
