Table 4-4 Isolation Between The Master Antenna And The Wi-Fi Antenna - Huawei EM820W Hardware Manual

HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide
Isolation
For a wireless device with multiple antennas, the power of different antennas is
coupled with each other. Antenna isolation is used to measure the power coupling.
The power radiated by an antenna might be received by an adjacent antenna, which
decreases the antenna radiation efficiency and affects the running of other devices.
To avoid this problem, evaluate the antenna isolation as sufficiently as possible at the
early stage of antenna design.
Antenna isolation depends on the following factors:
The master antenna must be placed as near as possible to the EM820W to minimize
the cable length. The slave antenna needs to be installed perpendicularly to the
master antenna. The slave antenna can be placed farther away from the EM820W.
Antenna isolation can be measured with a two-port vector network analyzer.
The following antenna isolation is recommended for the antennas on laptops:
If a Wi-Fi module is installed on the laptop, the following measures must be taken to
reduce mutual influence between the data card module and the Wi-Fi module:
Table 4-4 lists the requirements for the isolation between the master antenna and the
Wi-Fi antenna in different frequency bands according to the interference suppression
supported by the filter in different frequency bands.

Table 4-4 Isolation between the master antenna and the Wi-Fi antenna

Frequency
Band
UMTS2100
UMTS1900
UMTS850
UMTS900
Issue 01 (2010-12-09)
Efficiency of the slave antenna > 40% (–4 dB)
Efficiency of the GPS antenna > 50% (–3 dB)
Efficiency of the Wi-Fi antenna > 40% (–4 dB)
Distance between antennas
Antenna type
Antenna direction
Isolation between master and slave antennas < –12 dB
Isolation between the master antenna and the GPS antenna < –15 dB
Isolation between the slave antenna and the Wi-Fi antenna < –15 dB
Adding a bandpass filter to the Wi-Fi channel to filter the WCDMA, GSM850,
GSM900, DCS, and PCS signals
Ensuring sufficient isolation between the master antenna of the data card
module and the Wi-Fi antenna
Transmit
Frequency
1920–1980 MHz
1850–1910 MHz
824–849 MHz
880–915 MHz
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Copyright © Huawei Technologies Co., Ltd.
Conducted Ant
Transmit Isolator
Power (dBm) (dB)
24 11
24 11
24 10
24 10
RF Specifications
Wi-Fi Front End
Filter Attenuation
(dB)
34
34
36
36
20