Quectel EG91 Series Hardware Design page 63

LTE Module Series
EG91 Hardware Design
Figure 31: Microstrip Line Design on a 2-layer PCB
Figure 32: Coplanar Waveguide Design on a 2-layer PCB
Figure 33: Coplanar Waveguide Design on a 4-layer PCB (Layer 3 as Reference Ground)
Figure 34: Coplanar Waveguide Design on a 4-layer PCB (Layer 4 as Reference Ground)
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