V1.4 – Mar-11
User’s Manual
Page 25 of 39
8 Use of GPS Antennas
8.1 Connecting a GPS antenna to the GPS receiver
The ANT_EXT or ANT_INT pin is used to connect a GPS antenna to the receiver.
The design of the antenna connection has to be done strictly according to RF design
rules. A 50
Ω
PCB strip line is required. The following drawings shall explain the
guidelines. A major rule is to keep the strip line as short as possible. Additionally,
antenna ground (ANT_GND) should be routed to the ground plane of the PCB (the
ground plane is on a lower PCB layer) by vias as demonstrated in the drawing.
Figure 11: Antenna connector strip line A1084
Vias to Top Layer
Vias to GND Layer
50
Ω
strip line
GPS receiver solder pads
Top view
ANT_EXT
ANT_GND
ANT_EXT
ANT_GND
50
Ω
strip line
Top view
ANT_INT
ANT_GND
Motherboard Bottom Layer
Motherboard Top Layer
ANT_INT
ANT_GND
GPS Receiver
GPS Receiver
GPS Receiver
GPS Receiver