Ground Connection; Shielding; Antenna And Cabling - Sierra Wireless MC8301V Hardware Integration Manual

CDMA and GSM / UMTS Mini Card Hardware Integration Guide
Note: Values in this guide are
taken from the appropriate
product specification documents
(PSDs) (listed in
documents
, page
case of a discrepancy between
this document and the relevant
PSD, use the value listed in the
PSD.
22
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.

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.

Shielding

The module is fully shielded to protect against EMI and to
ensure compliance with FCC Part 15 ‐ "Radio Frequency
Devices" (or equivalent regulations in other jurisdictions).
Note: The module shields must NOT be removed.

Antenna and cabling

When selecting the antenna and cable, it is critical to RF perfor‐
mance to match antenna gain and cable loss.
Choosing the correct antenna and cabling
Related
11) — in the
Consider the following points for proper matching of antennas
and cabling:
The antenna (and associated circuitry) should have a
•
nominal impedance of 50  with a return loss 10 dB
across each frequency band of operation.
• The system gain value affects both radiated power and
regulatory (FCC, IC, CE, etc.) test results.
Developing custom antennas
Consider the following points when developing custom‐
designed antennas:
A skilled RF engineer should do the development to ensure
•
that the RF performance is maintained.
• Identify the bands that need to be supported, particularly
when both the MC57xx and MC8xxx will be installed in the
same platform. In this case, you may want to develop
separate antennas for maximum performance.
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