Antenna Gain Maximum Requirements - Fibocom G610 Hardware User Manual

specific type of cable that interfaces with their antenna and ask them to detail the RF losses of the cables
supplied along with the antenna. Typically, the cable length should be such that they have no more than
1-2dB of loss. Though the system will work with longer (lossy) cables, this will degrade GSM system
performance. Care should also be taken to ensure that the cable end
Connectors/terminations are well assembled to minimize losses and to offer a reliable, sturdy
connection to the Module sub-system. This is particularly important for applications where the module is
mounted on a mobile or portable environment where it is subject to shock and vibration.

6.2.3 Antenna Gain Maximum Requirements

Our FCC Grant imposes a maximum gain for the antenna subsystem: 2 dBi for the GSM850 band
and 2dBi for the 1900 band.
Warning: Excessive gain could damage sensitive RF circuits and void the warranty.
6.2.4 Antenna Matching
The module's RF connectors are designed to work with a 50-ohm subsystem. It is assumed that the
antenna chosen has matching internal to it to match between the 50-ohm RF connectors and the
antenna impedance.
6.2.5 PCB Design Considerations
• The antenna subsystem should be treated like any other RF system or component. It should be
isolated as much as possible from any noise generating circuitry including the interface signals via
filtering and shielding.
• As a general recommendation all components or chips operating at high frequencies such as
micro controllers, memory, DC/DC converts and other RF components should not be placed too close to
the module. When such cases exist, correct supply and ground de-coupling areas should be designed
and validated.
• Avoid placing the components around the RF connection and close to the RF line between the RF
antenna and the module.
• RF lines and cables should be as short as possible.
• If using coaxial cable it should not be placed close to devices operating at low frequencies. Signals like
charger circuits may require some EMI/RFI decoupling such as filter capacitors or ferrite beads.
• Adding external impedance matching to improve the match to your cable and antenna assemblies is
optional. Please contact the antenna vendor for matching requirements.
• For better ESD protection one can implement a shock coil to ground and place it close to the RF
G610 GPRS Module Hardware User Manual Page 46 of 47