User's Manual

LE920A4 HW User Guide Antenna(s)
Doc#: 1VV0301261 GPS/GNSS Antenna Requirements
Rev. 4.3 Page 65 of 123 2017-12-07
NOTE:
If Rx Diversity is not used/connected, disable the Diversity functionality using
the AT#RXDIV or AT#LRXDIV command (refer to Ref 1: LE920A4 AT
Command User Guide) and leave the Diversity pad AU9 unconnected.
GPS/GNSS Antenna Requirements
The module supports an active antenna.
It is recommended to use antennas as follows:
• An external active antenna (17dB typ. Gain, GPS only)
• An external active antenna plus GNSS pre-filter (17dB typ. Gain)
NOTE:
The external GNSS pre-Filter is required for the GLONASS application.
The GNSS pre-filter must meet the following requirements:
• Source and load impedance = 50 Ohm
• Insertion loss (1575.42 – 1576.42 MHz) = 1.4 dB (Max)
• Insertion loss (1565.42 – 1585.42 MHz) = 2.0 dB (Max)
•
Insertion loss (1597.5515
–
1605.886
MHZ) = 2.0
dB (Max)
NOTE:
It is recommended to add a DC block to the customer’s GPS application to
prevent damage to the module due to undesired DC voltage.
NOTE:
It is recommended to add PI matching network near the GPS connector on
the application board in case that RF matching is needed.
7.5.1. Combined GPS/GNSS Antenna
The use of combined RF/GPS/GNSS antenna is NOT recommended. This solution can
generate an extremely poor GPS/GNSS reception. In addition, the combination of
antennas requires an additional diplexer, which adds significant power loss in the RF path.