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Smart LTE Module Series
SC20 Hardware Design
SC20_Hardware_Design 78 / 130
1)
The bandwidth of LTE-TDD B41 for SC20-JL is 110MHz (2545MHz~2655MHz), and the corresponding
channel range is 40140~41240.
6.1.2. Main and Rx-diversity Antenna Interfaces Reference Design
A reference circuit design for main and Rx-diversity antenna interfaces is shown as below. A π-type
matching circuit should be reserved for better RF performance. The π-type matching components
(R1/C1/C2, R2/C3/C4) should be placed as close to the antennas as possible and are mounted according
to the actual debugging. C1, C2, C3 and C4 are not mounted and a 0Ω resistor is mounted on R1 and R2
respectively by default.
ANT_MAIN
R1 0R
C1
Module
Main
antenna
NM
C2
NM
R2 0R
C3
DRX
antenna
NM
C4
NM
ANT_DRX
Figure 31: Reference Circuit Design for Main and Rx-diversity Antenna Interfaces
6.1.3. Reference Design of RF Layout
For user’s PCB, the characteristic impedance of all RF traces should be controlled to 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 clearance between RF trace and 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.
NOTE