SE867-AGPS User Guide
1VV0300860 Rev. 3 - 2010-05-10
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 23 of 69
6.2.
GPS antenna PCB line guidelines
Ensure that the antenna line impedance is 50 ohm.
Keep the antenna line on the PCB as short as possible in order to limit losses.
Antenna line must have uniform characteristics (unchanging cross section and
dielectric constant). Meanders and abrupt curves should be avoided.
Discontinuity in the PCB GND plane should be avoided. Also, the GND plane should
NOT be used to route any other signal.
Surround (on the sides, above and below) the antenna line on PCB with GND, 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 GND vias every 2mm at least.
Place EM noisy devices as far away as possible from SE867-AGPS antenna line.
Keep the antenna line far away from the
SE867-AGPS power supply lines.
If EM noisy devices, such as fast switching ICs, are placed close to the PCB hosting
the SE867-AGPS, the antenna line should be realized in stripline technology (signal
trace between the up and down reference GND plan plus a coplanar GND guard
trace parallel to the signal trace),or shielded with a metal frame cover.
If EM noisy devices are NOT placed close to the PCB hosting the SE867-AGPS, the
antenna line should be realized in microstrip technology (signal trace on the top or
bottom layer with only one reference GND plane, plus coplanar GND guard trace
parallel to the signal trace), in order to reduce the ohmic losses of the trace.
6.3.
Antenna installation guidelines
Install the antenna in a place covered by the GPS signal.
Antenna shall not be installed inside metal cases.
Antenna shall be installed also according Antenna manufacturer instructions.
