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LTE Module Series
EC25 Hardware Design
EC25_Hardware_Design 74 / 112
5.1.3. Reference Design of RF Antenna Interface
Areference 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.
Figure 32: Reference Circuit of RF Antenna Interface
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.
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,
the distance between signal layer and reference ground (H), and the clearance between RF trace and
ground (S). Microstrip line or coplanar waveguide line is typically used in RF layout for characteristic
impedance control. The following are reference designs of microstrip line or coplanar waveguide line with
different PCB structures
NOTES