UMTS/HSPA(+) Module Series
UC200T-EM Hardware Design
UC200T-EM_Hardware_Design 44 / 68
ANT_MAIN
R1 0R
C1
Module
Main
antenna
NM
C2
NM
Figure 21: Reference Circuit of RF Antenna Interface
Place the
π-type matching components (R1/C1/C2) as close to the antenna as possible.
4.1.4.
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 traces and
grounds (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.
.
Figure 22: Microstrip Design on a 2-layer PCB
NOTE