Huawei MU736 Hardware Manual page 47

HUAWEI MU736 HSPA+ M.2 Module
Hardware Guide

In addition, the efficiency should be tested with the transmission cable.
S11 or VSWR
S11 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 antenna of MU736:



In addition, S11 is less important than the efficiency, and S11 has weak correlation to
the wireless performance.
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 primary antenna must be placed as near as possible to the MU736 to minimize
the cable length. The diversity antenna needs to be installed perpendicularly to the
primary antenna. The diversity antenna can be placed farther away from the MU736.
Antenna isolation can be measured with a two-port vector network analyzer.
The following antenna isolation is 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 antenna of MU736.
Issue 05 (2014-01-14)
Efficiency of the GPS antenna: ≥ 50%
S11 of the primary antenna ≤ –6 dB
S11 of the diversity antenna ≤ –6 dB
S11 of the GPS antenna ≤ –10 dB
Distance between antennas
Antenna type
Antenna direction
Isolation between the primary and diversity antennas ≤ –12 dB
Isolation between the primary antenna and the GPS antenna ≤ –15 dB
Isolation between the primary antenna and the Wi-Fi antenna ≤ –15 dB
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
RF Specifications
47