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HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide
Frequency
Band
GSM850
GSM900
DCS
PCS
S11 or VSWR
S11 (return loss) indicates the degree to which the input impedance of an antenna
matches the reference impedance (50 ohm). S11 shows the resonance feature and
impedance bandwidth of an antenna. Voltage standing wave ratio (VSWR) is another
expression of S11. S11 relates to the antenna efficiency. S11 can be measured with a
vector analyzer.
The following S11 values are recommended for the antennas on laptops:
Polarization
The polarization of an antenna is the orientation of the electric field vector that rotates
with time in the direction of maximum radiation.
The linear polarization is recommended for the antennas on laptops.
Envelope Correlation Coefficient
The envelope correlation coefficient indicates the correlation between different
antennas in a multi-antenna system (master antenna, diversity antenna, and MIMO
antenna). The correlation coefficient shows the similarity of radiation patterns, that is,
amplitude and phase, of the antennas. The ideal correlation coefficient of a diversity
antenna system or a MIMO antenna system is 0. A small value of the envelope
correlation coefficient between the master antenna and the slave antenna indicates a
high diversity gain. The envelope correlation coefficient depends on the following
factors:
The antenna correlation coefficient differs from the antenna isolation. Sufficient
antenna isolation does not represent a satisfactory correlation coefficient. For this
reason, the two indicators need to be evaluated separately.
Issue 01 (2010-12-09)
Transmit
Frequency
824–849 MHz
880–915 MHz
1710–1785 MHz
1850–1910 MHz
S11 of the master antenna < –6 dB
S11 of the slave antenna < –6 dB
S11 of the GSP antenna < –10 dB
S11 of the Wi-Fi antenna < –10 dB
Distance between antennas
Antenna type
Antenna direction
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Conducted
Ant
Transmit
Isolator
Power (dBm)
(dB)
33
18
33
18
30
17
30
17
RF Specifications
Wi-Fi Front End
Filter Attenuation
(dB)
36
36
34
34
21
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