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HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide RF Specifications
Issue 01 (2010-12-31)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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into account. The appropriate antenna gain prolongs the service life of relevant
batteries.
The following antenna gain is recommended for antennas on laptops:
z
Gain of the master antenna ≤ 3 dBi
z
Gain of the slave antenna ≤ 3 dBi
z
The antenna on a laptop consists of the antenna body and the relevant RF transmission
cable. Take the RF transmission cable inside the laptop into account when measuring any
of the preceding antenna indicators.
z
Huawei cooperates with various antenna suppliers who are able to make suggestions on
antenna design, for example, Amphenol, Skycross, Pulse etc.
4.4.2 Interference
Besides the antenna performance, the interference on the user board also affects the
radio performance (especially the TIS) of the module. To guarantee high performance
of the module, the interference sources on the user board must be properly controlled.
On the user board, there are various interference sources, such as the LCD, CPU,
audio circuits, and power supply. All the interference sources emit interference
signals that affect the normal operation of the module. For example, the module
sensitivity can be decreased due to interference signals. Therefore, during the design,
you need to consider how to lessen the effects of interference sources on the module.
To lessen the effects of interference sources on the module, you can use an LCD
with optimized performance, shield the LCD interference signals, shield the signal
cable of the board, or design filter circuits.
Huawei is capable of making technical suggestions on radio performance
improvement of the module.
4.4.3 GSM/WCDMA Antenna Requirements
The antenna for EM820W must fulfill the following requirements:
Table 4-5 GSM/WCDMA antenna requirements
GSM/WCDMA Antenna Requirements
Frequency range Depending on the frequency band(s) provided by the
network operator, the customer must use the most
suitable antenna for that/those band(s)