ZTE Corporation ZTEMC2261 Manuale Utente
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21
MC2261
Hardware Development Guide of Module Product
4. A
NTENNA
I
NTERFACE
The RF interface of the MC2261 Module has an impedance of 50 ohm. The module is capable of sustaining a total mismatch at
the antenna connector or pad without any damage, even when transmitting at maximum RF power.
The external antenna must be matched properly to achieve best performance regarding radiated power, DC-power
consumption, modulation accuracy and harmonic suppression. Antenna matching networks are not included on the MC2261 Module
PCB and should be placed in the host application.
Regarding the return loss, the Module provides the following values in the active band:
Table 4–1 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
The connection of the antenna or other equipment must be de coupled from DC voltage. This is necessary because the antenna
connector is DC coupled to ground via an inductor for ESD protection.
4.1. A
NTENNA
I
NSTALLATION
To suit the physical design of individual applications, the MC2261 offers two alternatives approached to connecting the
antenna:
■ Recommended approach: CS-G2-SS1S-1.6S antenna connector manufactured by Percsson assembled on the daughter board.
See Section 4.3 for details. CS-G2-SS1S-1.6D antenna connector manufactured by Percsson assembled on the component side
of the PCB (top view on Module). See Section 4.3 for details.
■ Antenna pad and grounding plane placed on the bottom side. See Section 4.2 for details.
The SSMB-50TKE-10 and NMM22-5017 connectors have been chosen as antenna reference point (ARP) for the ZTE reference
equipment submitted to type approve the MC2261 Module. All RF data specified throughout this manual are related to the ARP. For
compliance with the test results of the ZTE type approval you are advised to give priority to the connector, rather than using the
antenna pad.
NOTE: Both solutions can be applied alternatively. This means, if the antenna is connected to the pad, then the connector on the Module
must be left empty. If the antenna is connected to daughter board, the connector on the Module must be left empty too. And when the antenna is
connected to the Module connector, the pad is useless.
4.2. A
NTENNA
P
AD
The antenna pad of the module is soldered to the board on the customer design to connect with RF line.
For proper grounding connect the RF line to the ground plane on the bottom of the MC2261 Module which must be connected
to the ground plane of the application.
Consider that according to CDMA recommendations as 50Ω connector is mandatory for type approval measurements. It must
be ensured that the RF line which is connected to antenna pad should be controlled on 50Ω.
Notes on soldering
■ 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.