NEO-M8P - Hardware Integration Manual
UBX-15028081 - R05
Early Production Information
Design
Page 12 of 27
Stencil: 150
µ
m
10.4 mm [409.5 mil]
14.6 mm [575 mil]
12.2 mm [480 mil]
0.
8 mm
[31.
5
mi
l]
0.
6 mm
[23.
5
mi
l]
2.4
Antenna
With RTK operation, the antenna and its placement are critical system factors, both for the Base and Rover. The
minimum receiver signal strengths to track the signal phase are higher than conventional GNSS receivers, at about
34 dBHz, and require good antenna efficiency with a stable phase center. Hence, use of a relatively large ceramic
patch, i.e. 25 mm square or greater will provide reasonable performance in terms of efficiency and accuracy vs.
cost. For a Base station antenna installation, users should try to mitigate the effects of multi-path reception from
nearby objects or buildings. Use of a ground plane will minimize the effects of ground reflections and enhance
the antenna efficiency. For the Rover, use of a ground plane with a minimum diameter of 10 centimeter is
recommended. It is also recommended that the Rover antenna is positioned away from any potential reflectors on
the vehicle will give the best overall results. Exercise care with Rover vehicles that emit RF energy from motors etc.
as interference may extend into the GNSS band and couple into the GNSS antenna suppressing the wanted signal.
2.4.1
Antenna design with passive antenna
A design using a passive antenna requires more attention to the layout of the RF section. Typically, a passive
antenna is located near electronic components; therefore, care should be taken to reduce electrical noise that may
interfere with the antenna performance. Passive antennas do not require a DC bias voltage and can be directly
connected to the RF input pin
RF_IN
. Sometimes, they may also need a passive matching network to match the
impedance to 50
Ω
.
Figure 6 shows a minimal setup for a design with a good GNSS patch antenna.
Figure 6: Module design with passive antenna (for exact pin orientation see the
NEO-M8P Data Sheet
Figure 5: NEO-M8P paste mask / NEO-M8P footprint
12.2 mm [480.3 mil]
16.
0
m
m
[
63
0
mi
l]
1.0 mm
[39.3 mil]
0
.8
mm
[31.
5
mi
l]
0.8 mm
[31.5 mil]
3
.0
mm
[118.
1
mi
l]
1
.0
mm
[39.
3
mi
l]
1
.1
mm
[43.
3
mi
l]
