Installation Instructions

LISA-U2 series - System Integration Manual
UBX-13001118 - R19 Early Production Information Design-In
Page 128 of 175
2.4 Antenna guidelines
Antenna characteristics are essential for good functionality of the module. Antenna radiating performance has
direct impact on the reliability of connections over the Air Interface. A bad termination of the ANT pin (main RF
input/output) and the ANT_DIV pin (RF input for diversity receiver provided by LISA-U230 modules) can result in
poor performance of the module.
The following parameters should be checked:
Item
Recommendations
Impedance
50 Ω nominal characteristic impedance
Frequency Range
Depends on the LISA-U2 module HW version and on the Mobile Network used.
LISA-U260:
 824..960 MHz (GSM 850, GSM 900, UMTS B5)
 1710..1990 MHz (GSM 1800, GSM 1900, UMTS B2)
LISA-U270:
 824..960 MHz (GSM 850, GSM 900, UMTS B8)
 1710..2170 MHz (GSM 1800, GSM 1900, UMTS B1)
LISA-U200, LISA-U201, LISA-U230:
 824..960 MHz (GSM 850, GSM 900, UMTS B5, UMTS B6, UMTS B8)
 1710..2170 MHz (GSM 1800, GSM 1900, UMTS B1, UMTS B2, UMTS B4)
Input Power
>2 W peak
V.S.W.R
<2:1 recommended, <3:1 acceptable
Return Loss
S
11
<-10 dB recommended, S
11
<-6 dB acceptable
Table 46: General recommendation for GSM antenna
The antenna gain shall remain below the levels reported in the section 1.15.2.2 to preserve the
original u-blox FCC ID.
Some 2G and 3G bands are overlapping. This depends on worldwide band allocation for telephony services,
where different bands are deployed for different geographical regions.
If LISA-U2 series modules are planned for use on the entire supported bands, then an antenna that supports the
824..960 MHz and the 1710..2170 MHz frequency range should be selected. Otherwise, for fixed applications in
specific geographical region, antenna requirements can be relaxed for non-deployed frequency bands. See the
operating RF frequency bands table in LISA-U2 series Data Sheet [1] for the detailed uplink and downlink
frequency ranges of each supported band.
LISA-U230 modules provide 2G and 3G dynamic receive diversity (Rx diversity) capability to improve the quality
and reliability of the cellular link. This feature can be optionally used connecting a second antenna to the
ANT_DIV pin, to receive an RF input signal that is processed by the module to increase the performance.
It is recommended to properly connect the Rx diversity antenna to the ANT_DIV pin of LISA-U230
modules unless the 2G and 3G Rx diversity feature is disabled by AT command (see the u-blox AT
Commands Manual [2], +URXDIV command).
All the antenna guidelines and recommendations reported for the main Tx/Rx antenna design are applicable also
to the Rx diversity antenna design, even if the antenna for the Rx diversity is not used to transmit.