User's Manual

PHS8-US Hardware Interface Overview
5 Antenna Interfaces
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PHS8-US_HIO_v01.000 Page 29 of 40 2012-01-06
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5 Antenna Interfaces
5.1 GSM/UMTS Antenna Interface
The PHS8-US GSM/UMTS antenna interface comprises a main GSM/UMTS antenna as well
as an optional UMTS Rx diversity antenna to improve signal reliability and quality
1
. The inter-
face has an impedance of 50Ω. PHS8-US is capable of sustaining a total mismatch at the an-
tenna 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 PHS8-US PCB and should be placed in the host application, if the antenna does
not have an impendance of 50Ω.
Regarding the return loss PHS8-US provides the following values in the active band:
1.
By delivery default the optional UMTS Rx diversity antenna is configured as available for the module. To
avoid negative side effects and performance degradation it is recommended to disable the diversity an-
tenna 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 9: 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