Specifications

Cinterion
®
PDS5-E/PDS5-US Hardware Interface Overview
2.2 RF Antenna Interface
17
 PDS5_HIO_v04.000 2018-09-17
Confidential / Preliminary
Page 17 of 35
2.2 RF Antenna Interface
The RF interface has an impedance of 50. PDS5-E/PDS5-US is capable of sustaining a total
mismatch at the antenna line 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. Antenna matching networks are
not included on the PDS5-E/PDS5-US module and should be placed in the host application if
the antenna does not have an impedance of 50
.
Regarding the return loss PDS5-E/PDS5-US provides the following values in the active band:
2.2.1 Antenna Installation
The antenna is connected by soldering the antenna pad (ANT_GSM) 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 PDS5-E/PDS5-US‘s antenna pad.
Table 3: 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