Rf Connections; Shielding; Antenna And Cabling - Sierra Wireless AirPrime MC7455 Hardware Integration Manual

Hardware Integration Guide
12 Proprietary and Confidential - Contents subject to change
Table 3-3: GNSS Frequency Band Support
Band
Narrow-band GPS, Galileo
Wide-band GPS + GLONASS
Narrow-band BeiDou
Narrow-band GLONASS

RF Connections

When attaching antennas to the module:
• Use Hirose U.FL connectors (3 mm x 3 mm, low profile; model
U.FL #CL331-0471-0-10) to attach antennas to connection points on the
module.
Match coaxial connections between the module and the antenna to 50 .
•
• Minimize RF cable losses to the antenna; the recommended maximum cable
loss for antenna cabling is 0.5 dB.
• To ensure best thermal performance, mounting holes must be used to attach
(ground) the device to the main PCB ground or a metal chassis.
Note: If the antenna connection is shorted or open, the modem will not sustain permanent
damage.

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 recommended 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.
Frequencies
Rx: 1575.42 MHz
Rx: 1560–1606 MHz
Rx: 1561.098 MHz
Rx: 1601.72 MHz
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