ZTE Corporation ZTEMC2261 Manuale Utente
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25
MC2261
Hardware Development Guide of Module Product
Table 5–1 The requirement of dual band antenna
NOTE: TX refers to the transmit from the module into the antenna (Reverse Link of the CDMA system), and RX refers to the receive from the
antenna into the module (Forward Link of the CDMA system).
5.2. A
NTENNA
S
UBSYSTEM
The antenna sub-system and its design is a major part of the final product integration. Special attention and care should be
taken in adhering to the following guidelines.
5.2.1. A
NTENNA
S
PECIFICATIONS
Choice of the antenna cable (type, length, performance, RF loss, etc) and antenna connector (type + losses) can have a major
impact on the success of the design.
5.2.2. C
ABLE
L
OSS
All cables have RF losses. Minimizing the length of the cable between the antenna and the RF connectors on the module will
help obtain superior performance. High Quality/Low loss co-axial cables should be used to connect the antenna to the RF connectors.
Contact the antenna vendor for the specific type of cable that interfaces with their antenna and ask them to detail the RF losses of
the cables supplied along with the antenna. Typically, the cable length should be such that they have no more than 1-2dB of loss.
Though the system will work with longer (lossy) cables, this will degrade CDMA system performance. Care should also be taken to
ensure that the cable end connectors/terminations are well assembled to minimize losses and to offer a reliable, sturdy connection
to the Module sub-system. This is particularly important for applications where the module is mounted on a mobile or portable
environment where it is subject to shock and vibration.
5.2.3. A
NTENNA
G
AIN
M
INIMUM
R
EQUIREMENTS
It is recommended that the antenna chosen have at least 2 dBi gain in the cellular band and 4 dBi in the PCS band. The Antenna
subsystem shall also have at least 8 dB of return loss at the input with respect to a 50-ohm system.
5.2.4. A
NTENNA
G
AIN
M
AXIMUM
R
EQUIREMENTS
Our FCC Grant imposes a maximum gain for the antenna subsystem: 7 dBi for the Cellular band and 13dBi for the PCS band.
Warning: Excessive gain could damage sensitive RF circuits and void the warranty.
5.2.5. A
NTENNA
M
ATCHING
The module’s RF connectors are designed to work with a 50-ohm subsystem. It is assumed that the antenna chosen has
matching internal to it to match between the 50-ohm RF connectors and the antenna impedance.
Band
TX Frequency
RX Frequency
PCS
1850-1910 MHz
1930-1990 MHz
Cellular
824-849 MHz
869-894 MHz