NE310L2 Hardware Design Guide
1VV0301711 Rev. 2
Page 38 of 64
2021-06-22
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 NE310L2
ground pins
Table 21: NE310L2 Antenna pad requirements
The transmission line should be designed according to the following guidelines:
make sure that the transmission line’s characteristic impedance is 50ohm;
keep line on the PCB as short as possible, since the antenna line loss shall be less
than about 0.3 dB;
line geometry should have uniform characteristics, constant cross section, avoid
meanders and abrupt curves;
any kind of suitable geometry / structure (Microstrip, Stripline, Coplanar,
Grounded Coplanar Waveguide...) can be used to implement the printed
transmission line afferent the antenna;
if a Ground plane is required in line geometry, that plane shall be continuous and
sufficiently extended, so that the geometry can be as similar as possible to the
related canonical model;
keep, if possible, at least one layer of the PCB used only for the Ground plane; If
possible, use this layer as reference Ground plane for the transmission line;
it is advisable to surround (on both sides) the PCB transmission line with Ground,
avoiding that other signal tracks face directly the antenna line track;
avoid crossing any un-shielded transmission line footprint with other signal tracks
on different layers;
the ground surrounding the antenna line on PCB shall be strictly connected to the
main Ground Plane by means of via holes (at least once per 2mm), placed close to
the ground edges facing the line track;
place the noisy EM devices as far as possible from NE310L2 antenna line;
keep the antenna line far away from the NE310L2 power supply lines;
if EM noisy devices (such as fast switching ICs, LCD and so on) are present on the
PCB hosting the NE310L2, take care of the shielding of the antenna line by burying
it in an inner layer of PCB and surrounding it with the Ground planes, or shield it
with a metal frame cover;
if the noisy EM devices are not present around the line, the use of geometries such
as Microstrip or Grounded Coplanar Waveguide is preferable, since they typically
ensure less attenuation than a Stripline of the same length.
