Huawei MU736 Hardware Manual page 48

HUAWEI MU736 HSPA+ M.2 Module
Hardware Guide
Envelope Correlation Coefficient
The envelope correlation coefficient indicates the correlation between different
antennas in a multi-antenna system (primary 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 primary antenna and the diversity antenna
indicates a high diversity gain. The envelope correlation coefficient depends on the
following factors:
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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.
For the antennas on laptops, the recommended envelope correlation coefficient
between the primary antenna and the diversity antenna is smaller than 0.5.
Radiation Pattern
The radiation pattern of an antenna reflects the radiation features of the antenna in the
remote field region. The radiation pattern of an antenna commonly describes the
power or field strength of the radiated electromagnetic waves in various directions
from the antenna. The power or field strength varies with the angular coordinates (θ
and φ), but is independent of the radial coordinates.
The radiation pattern of half wave dipole antennas is omnidirectional in the horizontal
plane, and the incident waves of base stations are often in the horizontal plane. For
this reason, the receiving performance is optimal.
The following radiation patterns are recommended for the antenna of MU736:
Primary/Diversity/GPS/WIFI antenna: omnidirectional.
In addition, the diversity antenna's pattern should be complementary with the primary
antenna's pattern.
Gain and Directivity
The radiation pattern of an antenna represents the field strength of the radiated
electromagnetic waves in all directions, but not the power density that the antenna
radiates in the specific direction. The directivity of an antenna, however, measures the
power density that the antenna radiates.
Gain, as another important parameter of antennas, correlates closely to the directivity.
The gain of an antenna takes both the directivity and the efficiency of the antenna into
account. The appropriate antenna gain prolongs the service life of relevant batteries.
The following antenna gain is recommended for MU736:
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Issue 05 (2014-01-14)
Distance between antennas
Antenna type
Antenna direction
Gain of the primary antenna ≤ 2.5 dBi
Gain of the diversity antenna ≤ 2.5 dBi
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RF Specifications
48