User's Manual

HC25 Hardware Interface Overview
4.2 Antenna Pad
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HC25_HO_v00.220 Page 18 of 39 2007-03-20
Confidential / Preliminary
No matter which option you choose, ensure that the antenna pad does not come into contact
with the holding device or any other components of the host application. It needs to be sur-
rounded by a restricted area filled with air, which must also be reserved 1.4mm in height.
Figure 1: Restricted area around antenna pad (side and bottom view)
4.2 Antenna Pad
The antenna can be attached via contact springs.
If 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 HC25 type approval. The antenna pad is pro-
vided 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
50Ω 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.
HC25 material properties:
HC25 PCB: FR4
Antenna pad: Gold plated pad