LTE Standard Module Series
EG91 Series Hardware Design
EG91_Series_Hardware_Design 63 / 106
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 Pin No. I/O Description Comment
ANT_GNSS
(EG91-NA/-NS/-VX/-EX/-NAX/-
NAXD/-AUX)
49 AI GNSS antenna 50Ω impedance
Table 27: GNSS Frequency
Type Frequency Unit
GPS 1575.42±1.023 MHz
GLONASS 1597.5~1605.8 MHz
Galileo 1575.42±2.046 MHz
BeiDou 1561.098±2.046 MHz
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