Gnss Antenna Interface - Quectel EG91 Series Hardware Design

 Use impedance simulation tool to control the characteristic impedance of RF traces as 50Ω.
 The GND pins adjacent to RF pins should not be designed as thermal relief pads, and should be fully
connected to ground.
 The distance between the RF pins and the RF connector 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 vias around
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].

5.2. GNSS Antenna Interface

The GNSS antenna interface is only supported on EG91-NA/-NS/-VX/-EX. 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/-VX/-EX)
Table 27: GNSS Frequency
Type
GPS
GLONASS
Galileo
BeiDou
QZSS
A reference design of GNSS antenna is shown as below.
EG91_Hardware_Design
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
LTE Standard Module Series
EG91 Hardware Design
Comment
50Ω impedance
Unit
MHz
MHz
MHz
MHz
MHz
59 / 93