LTE Module Series
EC21 Hardware Design
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5.1.4. Reference Design of RF Layout
For user’s PCB, the characteristic impedance of all RF traces should be controlled as 50 ohm. The
impedan
ce 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
.
Figure 32: Microstrip Line Design on a 2-layer PCB
Figure 33: Coplanar Waveguide Line Design on a 2-layer PCB
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