Gnss Antenna Interface - Quectel EG91 Series Hardware Design

In order to ensure RF performance and reliability, the following principles should be complied with in RF
layout design:
 Use impedance simulation tool to control the characteristic impedanceof RF tracesas 50Ω.
 The GND pins adjacent to RF pins should not bedesigned as thermal relief pads, and should be fully
connected to ground.
 The distance between the RF pinsand the RFconnector should be as short as possible, and all the
right angle traces should be changed to curved ones.
There should be clearance area under the signal pin of the antenna connector or solder joint.

 The reference ground of RF traces should be complete. Meanwhile, adding some ground viasaround
RF traces and the reference ground could help to improve RF performance. The distance between
the ground vias and RF traces should be no less than two times the width of RF signal traces (2*W).
For more details about RF layout, please refer to document [5].
The GNSS antenna interface is only supported on EG91-NA/-NS/-V/-EC. The following tables show pin
definition and frequency specification of GNSS antenna interface.
Table 26: Pin Definition of GNSS Antenna Interface
Pin Name
ANT_GNSS
(EG91-NA/-NS/-V/-EC)
Table 27: GNSS Frequency
Type
GPS
GLONASS
Galileo
BeiDou
QZSS
A reference design of GNSS antenna is shown as below.
EG91_Hardware_Design

5.2. GNSS Antenna Interface

Pin No. I/O Description
49 AI GNSS antenna
Frequency
1575.42±1.023
1597.5~1605.8
1575.42±2.046
1561.098±2.046
1575.42
63 / 93
LTE Module Series
EG91 Hardware Design
Comment
50Ωimpedance
Unit
MHz
MHz
MHz
MHz
MHz