User's Manual

AHS3-W Hardware Interface Overview
5.1 GSM/UMTS Antenna Interface
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AHS3-W_HIO_v02.540a Page 30 of 41 2012-09-05
Confidential / Preliminary
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5.1.1 Antenna Installation
The antenna is connected by soldering the antenna pads (ANT_WGSM; ANT_DRX) and their
neighboring ground pads directly to the application’s PCB.
The distance between the antenna pads and their neighboring GND pads has been optimized
for best possible impedance. To prevent mismatch, special attention should be paid to these
pads on the application’ PCB.
The wiring of the antenna connection, starting from the antenna pad to the application’s anten-
na should result in a 50
line impedance. Line width and distance to the GND plane need to be
optimized with regard to the PCB’s layer stack.
To prevent receiver desensitization due to interferences generated by fast transients like high
speed clocks on the external application PCB, it is recommended to realize the antenna con-
nection line using embedded Stripline rather than Micro-Stripline technology.
For type approval purposes, the use of a 50
coaxial antenna connector (U.FL-R-SMT) might
be necessary. In this case the U.FL-R-SMT connector should be placed as close as possible
to AHS3-W‘s antenna pad.