AirPrime EM7700 Hardware Integration Guide
12
Proprietary and Confidential
4112206
Note: If the antenna connection is shorted or open, the modem will not sustain permanent
damage.
Ground connection
When connecting the module to system ground:
•
Prevent noise leakage by establishing a very good ground connection to the
module through the host connector.
•
Connect to system ground using the three mounting holes at the top and
bottom of the module.
•
Minimize ground noise leakage into the RF.
Depending on the host board design, noise could
potentially
be coupled to
the module from the host board. This is mainly an issue for host designs that
have signals traveling along the length of the module, or circuitry operating at
both ends of the module interconnects.
Shielding
The module is fully shielded to protect against EMI and must not be removed.
Antenna and cabling
When selecting the antenna and cable, it is critical to RF performance to match
antenna gain and cable loss.
Choosing the correct antenna and cabling
When matching antennas and cabling:
•
The antenna (and associated circuitry) should have a nominal impedance of
50
with a return loss of better than 10 dB across each frequency band of
operation.
•
The system gain value affects both radiated power
and
regulatory (FCC, IC,
CE, etc.) test results.
Designing custom antennas
Consider the following points when designing custom antennas:
•
A skilled RF engineer should do the development to ensure that the RF
performance is maintained.
•
If both UMTS and CDMA modules will be installed in the same platform, you
may want to develop separate antennas for maximum performance.
Summary of Contents for AirPrime EM7700
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