GE866-QUAD Hardware User Guide
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Page 38 of 82
Mod. 0805 2011-07 Rev.2
In the case that the antenna is not directly developed on the same PCB, hence
directly connected at the antenna pad of the GE866-QUAD, then a PCB line is needed
in order to connect with it or with its connector.
This transmission line shall fulfill the following requirements:
ANTENNA LINE ON PCB REQUIREMENTS
Impedance
50 ohm
Max Attenuation
0,3 dB
No coupling with other signals allowed
Cold End (Ground Plane) of antenna shall be equipotential to the
GE866-QUAD ground pins
This transmission line should be designed according to the following guidelines:
•
Ensure that the antenna line impedance is 50 ohm;
•
Keep the antenna line on the PCB as short as possible, since the antenna line
loss shall be less than 0,3 dB;
•
Antenna line must have uniform characteristics, constant cross section, avoid
meanders and abrupt curves;
•
Keep, if possible, one layer of the PCB used only for the Ground plane;
•
Surround (on the sides, over and under) the antenna line on PCB with Ground,
avoid having other signal tracks facing directly the antenna line track;
•
The ground around the antenna line on PCB has to be strictly connected to the
Ground Plane by placing vias every 2mm at least;
•
Place EM noisy devices as far as possible from GE866-QUAD antenna line;
•
Keep the antenna line far away from the GE866-QUAD power supply lines;
•
If you have EM noisy devices around the PCB hosting the GE866-QUAD, such as
fast switching ICs, take care of the shielding of the antenna line by burying it
inside the layers of PCB and surround it with Ground planes, or shield it with a
metal frame cover.
•
If you don't have EM noisy devices around the PCB of GE866-QUAD, by using a
micro strip on the superficial copper layer for the antenna line, the line
attenuation will be lower than a buried one.