LTE-A Module Series
EG18 Hardware Design
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5.3. 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 spacing 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 38: Microstrip Design on a 2-layer PCB
Figure 39: Coplanar Waveguide Design on a 2-layer PCB
Figure 40: Coplanar Waveguide Design on a 4-layer PCB (Layer 3 as Reference Ground)
