Operating Frequency - Quectel EG915U Series Hardware Design

5.1.4. Operating Frequency

For user's PCB, the characteristic impedance of all RF traces should be controlled as 50 Ω. The
impedance of the RF traces is usually determined by the trace width (W), the materials' dielectric constant,
the height from the reference ground to the signal layer (H), and the spacing between the RF traces and
the ground (S). Microstrip or coplanar waveguide is typically used in RF layout to control characteristic
impedance. The following are reference designs of microstrip or coplanar waveguide with different PCB
structures.
.
EG915U_Series_Hardware_Design
Module
ANT_MAIN
ANT_BT/
WIFI_SCAN
Figure 28: Reference Circuit of RF Antenna
Figure 29: Microstrip Design on a 2-layer PCB
Main
antenna
R1 0R
C2
C1
NM
NM
Wi-Fi Scan/
R2 0R
antenna
C4
C3
NM
NM
LTE Standard Module Series
58 / 91