Rf Integration; Rf Connection; Ground Connection - Sierra Wireless MC5720 Hardware Integration Manual

3: RF Integration

Note: To disconnect the
antenna, make sure you use the
Hirose U.FL connector removal
tool (P/N UFL-LP-N-2(01) to
prevent damage to the module
or coaxial cable assembly.
Rev 0.92 Nov.05

RF connection

Consider the following when attaching an antenna to the
module:
Use a Hirose U.FL connector (model
•
U.FL #CL331‐0471‐0‐10) to attach an antenna to a
connection point on the module, as shown in Figure 3‐1
(The main RF connector on the top side; the diversity RF
connector on the bottom side).
Match coaxial connections between the module and the
•
antenna to 50 Ω.
• Minimize RF cable losses to the antenna; the recommended
maximum cable loss for antenna cabling is 0.5 dB.
Figure 3-1: Antenna connection points and mounting holes

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 two mounting holes at
•
the top of the module (as shown in Figure 3‐1).
• 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.
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