
NE866B1_Hardware_Design_Guide
1VV0301354 Rev. 6
Page
47
of
70
2018-02-28
6.5.2.
PCB design guidelines
When using the NB866B1, since there's no antenna connector on the module, the
antenna must be connected to the NB866B1 antenna pad by means of a transmission line
implemented on the PCB.
This transmission line shall fulfil the following requirements:
The 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 NB866B1 antenna line;
•
Keep the antenna line far away from the NB866B1 power supply lines;
•
If you have EM noisy devices around the PCB hosting the NB866B1, 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.
Item
Value
Characteristic
Impedance
50 ohm
Max Attenuation
0.3 dB
Coupling
Coupling with other signals shall be avoided
Ground Plane
Cold End (Ground Plane) of antenna shall be
equipotential to the NB866B1 ground pins