Huawei MC509 Series Hardware Manual page 48

HUAWEI MC509 Series CDMA LGA Module
Hardware Guide
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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 MC509:
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In addition, S11 is less important than the efficiency, and S11 has weak correlation to
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:
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The primary antenna must be placed as near as possible to the MC509 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 MC509
Antenna isolation can be measured with a two-port vector network analyzer.
The following antenna isolation is recommended for the antennas on laptops:
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Issue 02 (2013-05-06)
Efficiency of the primary antenna: ≥ 40% (below 960MHz); ≥ 50% (over
1710MHz)
Efficiency of the diversity antenna: ≥ half of the efficiency of the primary
antenna in receiving band
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 primary and diversity antennas ≤ –12 dB
Isolation between the primary (diversity) antenna and the GPS antenna ≤ –
15 dB
Isolation between the primary (diversity) antenna and the Wi-Fi antenna ≤ –
15 dB
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RF Specifications
48