HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide
RF Specifications
Issue 01 (2010-12-09)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
26
Figure 4-2
Recommended antenna positions
z
It is recommended that the antenna pattern be designed based on the horizontal
polarized omnidirectional pattern that facilitates the reception of strong signals
especially in outdoor environments.
z
Besides the module antennas, a laptop has other internal antennas, such as the
WLAN antenna. Therefore, when designing the module antennas, the
requirement on the isolation between module antennas and other laptop
antennas should be considered. Ensure that proper distance is maintained
between antennas if possible. To reduce the interference between antennas, it is
recommended that an antenna is not designed close to another one.
z
Carefully design the metallic components (such as the external frame of the
metallic shell) in and near the antenna area by considering the effects on the
antenna performance (such as whether the frequency offset of the antenna
occurs and whether the antenna pattern is deformed).
4.6 ESD Protection for the Antenna Interface
In practical application, pay attention to the ESD protection for the antenna interface
of the EM820W module. Incorrect operation may result in permanent damage to the
RF components.
Figure 4-3 shows the ESD protection circuit recommended for the antenna interface.