Reference Design Of Rf Antenna Interface; Reference Design Of Rf Layout - Quectel EC25-AUX Hardware Design

LTE-FDD B71

5.1.3. Reference Design of RF Antenna Interface

A reference design of ANT_MAIN and ANT_DIV antenna pads is shown as below. A π-type matching
circuit should be reserved for better RF performance. The capacitors are not mounted by default.
NOTES
1. Keep a proper distance between the main antenna and the Rx-diversity antenna to improve the
receiving sensitivity.
2. ANT_DIV function is enabled by default.
receive diversity. Please refer to document [2] for details.
3. Place the π-type matching components (R1&C1&C2, R2&C3&C4) as close to the antenna as
possible.

5.1.4. Reference Design of RF Layout

For user's PCB, the characteristic impedance of all RF traces should be controlled as 50Ω. The
impedance of the RF traces is usually determined by the trace width (W), the materials' dielectric constant,
height from the reference ground to the signal layer (H), and the space between the RF trace and the
ground (S). Microstrip and coplanar waveguide are typically used in RF layout to control characteristic
impedance. The following figures are reference designs of microstrip or coplanar waveguide with different
PCB structures.
EC25_Hardware_Design
663~698
Figure 33: Reference Circuit of RF Antenna Interface
AT+QCFG="diversity",0
LTE Standard Module Series
EC25 Hardware Design
617~652
command can be used to disable
MHz
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