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 an impedance simulation tool to accurately control the characteristic impedance of RF traces to
50 Ω.
 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. The recommended trace angle is 135°.
 There should be clearance 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 x W).
 Keep RF traces away from interference sources, and avoid intersection and paralleling between
traces on adjacent layers.
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/-NAX/-NAXD/-AUX. 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/-NAX/-
NAXD/-AUX)
Table 27: GNSS Frequency
Type
GPS
GLONASS
Galileo
BeiDou
EG91_Series_Hardware_Design
Pin No. I/O
49 AI
Frequency
1575.42±1.023
1597.5~1605.8
1575.42±2.046
1561.098±2.046
LTE Standard Module Series
EG91 Series Hardware Design
Description Comment
GNSS antenna 50Ω impedance
Unit
MHz
MHz
MHz
MHz
63 / 106