Specifications

XT55 Hardware Interface Description
Confidential / Preliminary
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XT55_hd_v00.02 Page 80 of 116 17.03.2004
5.1.2 GSM antenna pad
The antenna can be soldered to the pad, or attached via contact springs. To help you ground
the antenna, XT55 comes with a grounding plane located close to the antenna pad. The
positions of both pads can be seen from Figure 52.
When you decide to use the antenna pad take into account that the pad has not been
intended as antenna reference point (ARP) for the Siemens XT55 type approval. The
antenna pad is provided only as an alternative option which can be used, for example, if the
recommended Hirose connection does not fit into your antenna design.
Also, consider that according to the GSM recommendations TS 45.005 and TS 51.010-01 a
50" connector is mandatory for type approval measurements. This requires GSM devices
with an integral antenna to be temporarily equipped with a suitable connector or a low loss
RF cable with adapter.
To prevent damage to the module and to obtain long-term solder joint properties you are
advised to maintain the standards of good engineering practice for soldering.
XT55 material properties:
XT55 PCB: FR4
Antenna pad: Gold plated pad
Suitable cable types:
For direct solder attachment, we suggest to use the following cable types:
· RG316/U 50 Ohm coaxial cable
· 1671A 50 Ohm coaxial cable
Suitable cables are offered, for example, by IMS Connector Systems. For further details and
other cable types please contact http://www.imscs.com
.
5.2 Installing the GPS antenna
In order to receive satellite signals an additional GPS antenna must be connected to the
GPS part of the XT55 module. The position of the GPS antenna connector can be found in
Figure 37 and Figure 53. Recommended devices which can be mounted onto the Hirose
connector are available in Chapter 9.
Figure 37: GPS antenna connector (U.FL-R-SMT connector)