User's Manual

PXS8 Hardware Interface Description
5 Antenna Interfaces
33
PXS8_HD_v03.000 Page 30 of 41 2012-11-30
Confidential / Preliminary

5 Antenna Interfaces
5.1 GSM/UMTS/CDMA Antenna Interface
The PXS8 GSM/UMTS/CDMA antenna interface comprises a main GSM/UMTS/CDMA anten-
na as well as an optional UMTS/CDMA Rx diversity antenna to improve signal reliability and
quality
1
. The interface has an impedance of 50. PXS8 is capable of sustaining a total mis-
match at the antenna interface without any damage, even when transmitting at maximum RF
power.
The external antenna must be matched properly to achieve best performance regarding radi-
ated power, modulation accuracy and harmonic suppression. Matching networks are not in-
cluded on the PXS8 PCB and should be placed in the host application, if the antenna does not
have an impedance of 50
.
Regarding the return loss PXS8 provides the following values in the active band:
1.
By delivery default the optional UMTS/CDMA Rx diversity antenna is configured as available for the mo-
dule. To avoid negative side effects and performance degradation it is recommended to disable the di-
versity antenna path if
- the host application does not support a diversity antenna
- the host application includes a diversity antenna - but a 3G network simulator is used for development
and performance tests.
Please refer to [1] for details on how to configure antenna settings.
Table 10: Return loss in the active band
State of module Return loss of module Recommended return loss of application
Receive >
8dB > 12dB
Transmit not applicable >
12dB
Idle <
5dB not applicable