User's Manual

LTE Module BEC CBRS-12 User Manual
71
layout design:
 Use an impedance simulation tool to accurately control the characteristic impedance of RF traces to
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 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 as wide as RF signal traces (2*W).
5.4. Antenna Installation
5.4.1. Antenna Requirements
The following table shows the requirements on main antenna, Rx-diversity antenna and GNSS antenna.
Table 35: Antenna Requirements
Type Requirements
GNSS
1)
Frequency range: 1559MHz~1609 MHz
Polarization: RHCP or linear
VSWR: <2 (Typ.)
Passive antenna gain: >0dBi
Active antenna noise figure: <1.5dB
Active antenna gain: >0dBi
Active antenna embedded LNA gain: <17dB
LTE
VSWR: ≤ 2
Efficiency: >30%
Max Input Power: 50W
Input Impedance: 50Ω
Cable Insertion Loss <2dB
(LTE B42/B48)
1)
It is recommended to use a passive GNSS antenna when LTE B13 or B14 is supported, as the use of
active antenna may generate harmonics which will affect the GNSS performance.
NOTE