User's Manual

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Note d’étude / Technical document : URDx– OTL 5635.1– 007 / 70 230 Edition 03
Document Sagem Communications Reproduction et divulgation interdites
Sagem Communications document. Reproduction and disclosure prohibited
6.2 GROUND LINK AREA
Warning: Sagem communications emphasizes the fact that a good ground contact is needed between the
module shielding and the MMI board to have the best radio performances (spurious, sensitivity…)
Solder the three pads of the shielding on the ground pads of MMI board, then the HiLo module will have a good
ground contact with the MMI board.
Figure 19: How to ground HiLo to MMI board
6.3 LAYOUT
Warning: Isolate RF line and antenna from others bus or signals
• No signals on 50 ohms area and if that is not possible, add ground shielding using different layers.
• Do not add any ground layer under the antenna contact area.
• Be careful on the position of the network LED (sometimes situated in front of the antenna pad ...)
6.4 MECHANICAL SURROUNDING
• Avoid any metallic part around the antenna area
• Keep jacks, FPCs and battery contact far from antenna area (FLEX)
• FPC has to be a shielded one
6.5 OTHER RECOMMENDATIONS – TESTS FOR PRODUCTION/DESIGN
Sagem communications guarantees the RF performances in conductive mode but strongly recommends
making RF measurements in an anechoic chamber in radiated mode (tests conditions for FTA): the radiated
performances strongly depend on radio integration (layout, antenna, matching circuit, ground area…..)
Solder on ground
pads of MMI board
Bottom view of HiLo
RF Spring (on top)
Connector (on top)