User's Manual

Cinterion
®
ELS61-US Hardware Interface Overview
2.3 RF Antenna Interface
21
 ELS61-US_HIO_v00.281 2016-02-11
Confidential / Preliminary
Page 18 of 40
2.3 RF Antenna Interface
The ELS61-US UMTS/LTE antenna interface comprises a UMTS/LTE main antenna as well as
a UMTS/LTE Rx diversity antenna to improve signal reliability and quality
1
. The RF interface
has an impedance of 50
Ω. ELS61-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 ELS61-US module and should be placed in the host application if the an-
tenna does not have an impedance of 50
Ω.
Regarding the return loss ELS61-US provides the following values in the active band:
1. By delivery default the UMTS/LTE Rx diversity antenna is configured as available for the module since
its usage is mandatory for LTE. Please refer to [1] for details on how to configure antenna settings.
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