HUAWEI ME909 Series Mini PCIe Module

 

Hardware Guide

RF Specifications

Distance between antennas

Antenna type

Antenna direction

The primary antenna must be placed as near as possible to the ME909 module 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 ME909 module. Antenna isolation can be measured with a two-port vector network analyzer.

The following antenna isolation is recommended for the antennas on laptops:

Isolation between the primary and diversity antennas: ≤ –12 dB

Isolation between the primary(diversity) antenna and the GPS antenna: ≤

–15 dB

Isolation between the primary antenna and the Wi-Fi antenna: ≤ –15 dB

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 ME909 module.

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 from‎the‎antenna.‎The‎power‎or‎field‎strength‎varies‎with‎the‎angular‎coordinates‎(θ‎ and‎φ),‎but‎is‎independent‎of‎the‎radial 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 ME909 module.

Primary/Diversity/GPS antenna: omnidirectional

In addition, the diversity‎antenna’s pattern should be complementary with the primary’s.

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:

Distance between antennas

Antenna type

 

Huawei Proprietary and Confidential

30

Issue 0.1 (2013-06-09)

Copyright © Huawei Technologies Co., Ltd.

 

Page 30
Image 30
Huawei ME909 manual Polarization